DataSet.Merge 方法

public:
 void Merge(cli::array <System::Data::DataRow ^> ^ rows);

public void Merge (System.Data.DataRow[] rows);

member this.Merge : System.Data.DataRow[] -> unit

Public Sub Merge (rows As DataRow())

参数

注解

Merge方法用于合并 DataSet 具有很大架构的两个对象。The Merge method is used to merge two DataSet objects that have largely similar schemas. 通常在客户端应用程序上使用合并，以将数据源中的最新更改合并到现有中 DataSet 。A merge is typically used on a client application to incorporate the latest changes from a data source into an existing DataSet. 这允许客户端应用程序使用 DataSet 数据源中的最新数据进行刷新。This allows the client application to have a refreshed DataSet with the latest data from the data source.

Merge方法通常在一系列过程的末尾调用，这些过程涉及验证更改、协调错误、使用更改更新数据源，最后刷新现有 DataSet 。The Merge method is typically called at the end of a series of procedures that involve validating changes, reconciling errors, updating the data source with the changes, and finally refreshing the existing DataSet.

在客户端应用程序中，通常有一个按钮，用户可以单击该按钮来收集更改的数据并对其进行验证，然后再将其发送回中间层组件。In a client application, it is common to have a single button that the user can click that gathers the changed data and validates it before sending it back to a middle-tier component. 在此方案中， GetChanges 首先调用方法。In this scenario, the GetChanges method is first invoked. 该方法将返回第二个 DataSet 优化用于验证和合并的。That method returns a second DataSet optimized for validating and merging. 此第二个 DataSet 对象仅包含已 DataTable 更改的和 DataRow 对象，从而导致了原始的子集 DataSet 。This second DataSet object contains only the DataTable and DataRow objects that were changed, resulting in a subset of the original DataSet. 此子集通常较小，因此更有效地传递回中间层组件。This subset is generally smaller and thus more efficiently passed back to a middle-tier component. 然后，中间层组件使用存储过程中的更改来更新原始数据源。The middle-tier component then updates the original data source with the changes through stored procedures. 然后，中间层可以 DataSet 通过再次运行原始查询来发送回包含数据源中的原始数据和最新数据 (的新数据) ，也可以从数据源向后发送回已对其进行的任何更改的子集。The middle tier can then send back either a new DataSet that includes original data and the latest data from the data source (by running the original query again), or it can send back the subset with any changes that have been made to it from the data source. (例如，如果数据源自动创建唯一的主键值，则这些值可以传播回客户端应用程序。 ) 在任何一种情况下，返回的都 DataSet 可以 DataSet 通过 Merge 方法合并回客户端应用程序的原始中。(For example, if the data source automatically creates unique primary key values, these values can be propagated back to the client application.) In either case, the returned DataSet can be merged back into the client application's original DataSet with the Merge method.

Merge调用方法时，将比较两个对象的架构， DataSet 因为架构可能已更改。When the Merge method is called, the schemas of the two DataSet objects are compared because it is possible that the schemas may have been changed. 例如，在企业对企业方案中，可能已通过自动化过程将新列添加到了 XML 架构。For example, in a business-to-business scenario, new columns may have been added to an XML schema by an automated process. 如果源 DataSet 包含架构元素 (添加了 DataColumn 目标中缺少的对象) ，则可以通过将参数设置为来将架构元素添加到目标中 missingSchemaAction MissingSchemaAction.Add 。If the source DataSet contains schema elements (added DataColumn objects) that are missing in the target, the schema elements can be added to the target by setting the missingSchemaAction argument to MissingSchemaAction.Add. 在这种情况下，合并的 DataSet 包含已添加的架构和数据。In that case, the merged DataSet contains the added schema and data.

合并架构后，数据将合并。After merging schemas, the data is merged.

在将新源合并 DataSet 到目标时，值为、或的任何源行都将与 DataRowState Unchanged Modified Deleted 具有相同的主键值的目标行匹配。When merging a new source DataSet into the target, any source rows with a DataRowState value of Unchanged, Modified, or Deleted are matched to target rows with the same primary key values. 值为的源行与新源行的 DataRowState Added 主键值相同的新目标行匹配。Source rows with a DataRowState value of Added are matched to new target rows with the same primary key values as the new source rows.

在合并过程中，将禁用约束。During a merge, constraints are disabled. 如果在合并结束时无法启用任何约束， ConstraintException 则在禁用约束时，将生成并保留合并的数据。If any constraints cannot be enabled at the end of a merge, a ConstraintException is generated and the merged data is retained while the constraints are disabled. 在这种情况下， EnforceConstraints 属性设置为 false ，并且所有无效行都标记为 "错误"。In this case, the EnforceConstraints property is set to false, and all rows that are invalid are marked in error. 在尝试将属性重置为之前，必须解决这些错误 EnforceConstraints true 。The errors must be resolved before attempting to reset the EnforceConstraints property to true.

另请参阅

• 在 ADO.NET 中使用数据集Using DataSets in ADO.NET

public:
 void Merge(System::Data::DataSet ^ dataSet);

public void Merge (System.Data.DataSet dataSet);

member this.Merge : System.Data.DataSet -> unit

Public Sub Merge (dataSet As DataSet)

参数

例外

示例

下面的示例对使用 GetChanges 、更新和 Merge 方法 DataSet 。The following example uses the GetChanges, Update, and Merge methods on a DataSet.

private void DemonstrateMerge()
{
    // Create a DataSet with one table, two columns, and three rows.
    DataSet dataSet = new DataSet("dataSet");
    DataTable table = new DataTable("Items");
    DataColumn idColumn = new DataColumn("id",
        Type.GetType("System.Int32"));
    idColumn.AutoIncrement=true;
    DataColumn itemColumn = new DataColumn("Item",
        Type.GetType("System.Int32"));

    // DataColumn array to set primary key.
    DataColumn[] keyColumn= new DataColumn[1];
    DataRow row;

    // Create variable for temporary DataSet.
    DataSet changeDataSet;

    // Add columns to table, and table to DataSet.
    table.Columns.Add(idColumn);
    table.Columns.Add(itemColumn);
    dataSet.Tables.Add(table);

    // Set primary key column.
    keyColumn[0]= idColumn;
    table.PrimaryKey=keyColumn;

    // Add ten rows.
    for(int i = 0; i <10;i++)
    {
        row=table.NewRow();
        row["Item"]= i;
        table.Rows.Add(row);
    }

    // Accept changes.
    dataSet.AcceptChanges();
    PrintValues(dataSet, "Original values");

    // Change two row values.
    table.Rows[0]["Item"]= 50;
    table.Rows[1]["Item"]= 111;

    // Add one row.
    row=table.NewRow();
    row["Item"]=74;
    table.Rows.Add(row);

    // Insert code for error checking. Set one row in error.
    table.Rows[1].RowError= "over 100";
    PrintValues(dataSet, "Modified and New Values");
    // If the table has changes or errors, create a subset DataSet.
    if(dataSet.HasChanges(DataRowState.Modified |
        DataRowState.Added)& dataSet.HasErrors)
    {
        // Use GetChanges to extract subset.
        changeDataSet = dataSet.GetChanges(
            DataRowState.Modified|DataRowState.Added);
        PrintValues(changeDataSet, "Subset values");
        // Insert code to reconcile errors. In this case reject changes.
        foreach(DataTable changeTable in changeDataSet.Tables)
        {
            if (changeTable.HasErrors)
            {
                foreach(DataRow changeRow in changeTable.Rows)
                {
                    //Console.WriteLine(changeRow["Item"]);
                    if((int)changeRow["Item",
                        DataRowVersion.Current ]> 100)
                    {
                        changeRow.RejectChanges();
                        changeRow.ClearErrors();
                    }
                }
            }
        }
        PrintValues(changeDataSet, "Reconciled subset values");
        // Merge changes back to first DataSet.
        dataSet.Merge(changeDataSet);
        PrintValues(dataSet, "Merged Values");
    }
}

private void PrintValues(DataSet dataSet, string label)
{
    Console.WriteLine("\n" + label);
    foreach(DataTable table in dataSet.Tables)
    {
        Console.WriteLine("TableName: " + table.TableName);
        foreach(DataRow row in table.Rows)
        {
            foreach(DataColumn column in table.Columns)
            {
                Console.Write("\table " + row[column] );
            }
            Console.WriteLine();
        }
    }
}

 Private Sub DemonstrateMerge()
     ' Create a DataSet with one table, two columns, and three rows.
     Dim dataSet As New DataSet("dataSet")
     Dim table As New DataTable("Items")
     Dim idColumn As New DataColumn("id", Type.GetType("System.Int32"))
     idColumn.AutoIncrement = True
     Dim itemColumn As New DataColumn("Item", Type.GetType("System.Int32"))

     ' DataColumn array to set primary key.
     Dim keyColumn(0) As DataColumn
     Dim row As DataRow

     ' Create variable for temporary DataSet. 
     Dim changeDataSet As DataSet

     ' Add columns to table, and table to DataSet.   
     table.Columns.Add(idColumn)
     table.Columns.Add(itemColumn)
     dataSet.Tables.Add(table)

     ' Set primary key column.
     keyColumn(0) = idColumn
     table.PrimaryKey = keyColumn

     ' Add ten rows.
     Dim i As Integer
     For i = 0 To 9
         row = table.NewRow()
         row("Item") = i
         table.Rows.Add(row)
     Next i

     ' Accept changes.
     dataSet.AcceptChanges()
     PrintValues(dataSet, "Original values")

     ' Change two row values.
     table.Rows(0)("Item") = 50
     table.Rows(1)("Item") = 111

     ' Add one row.
     row = table.NewRow()
     row("Item") = 74
     table.Rows.Add(row)

     ' Insert code for error checking. Set one row in error.
     table.Rows(1).RowError = "over 100"
     PrintValues(dataSet, "Modified and New Values")

     ' If the table has changes or errors, create a subset DataSet.
     If dataSet.HasChanges(DataRowState.Modified Or DataRowState.Added) _
        And dataSet.HasErrors Then

         ' Use GetChanges to extract subset.
         changeDataSet = dataSet.GetChanges(DataRowState.Modified _
            Or DataRowState.Added)
         PrintValues(changeDataSet, "Subset values")

         ' Insert code to reconcile errors. In this case, reject changes.
         Dim changeTable As DataTable
         For Each changeTable In  changeDataSet.Tables
             If changeTable.HasErrors Then
                 Dim changeRow As DataRow
                 For Each changeRow In  changeTable.Rows
                     'Console.WriteLine(changeRow["Item"]);
                     If CInt(changeRow("Item", _
                        DataRowVersion.Current)) > 100 Then
                         changeRow.RejectChanges()
                         changeRow.ClearErrors()
                     End If
                 Next changeRow
             End If
         Next changeTable
         PrintValues(changeDataSet, "Reconciled subset values")

         ' Merge changes back to first DataSet.
         dataSet.Merge(changeDataSet)
         PrintValues(dataSet, "Merged Values")
     End If
 End Sub
 
Private Sub PrintValues(dataSet As DataSet, label As String)
     Console.WriteLine(ControlChars.Cr & label)
     Dim table As DataTable
     For Each table In  dataSet.Tables
         Console.WriteLine("TableName: " & table.TableName)
         Dim row As DataRow
         For Each row In  table.Rows
             Dim column As DataColumn
             For Each column In  table.Columns
                 Console.Write(ControlChars.Tab & " " _
                    & row(column).ToString())
             Next column
             Console.WriteLine()
         Next row
     Next table
End Sub

注解

Merge方法用于合并 DataSet 具有很大架构的两个对象。The Merge method is used to merge two DataSet objects that have largely similar schemas. 通常在客户端应用程序上使用合并，以将数据源中的最新更改合并到现有中 DataSet 。A merge is typically used on a client application to incorporate the latest changes from a data source into an existing DataSet. 这允许客户端应用程序使用 DataSet 数据源中的最新数据进行刷新。This allows the client application to have a refreshed DataSet with the latest data from the data source.

Merge方法通常在一系列过程的末尾调用，这些过程涉及验证更改、协调错误、使用更改更新数据源，最后刷新现有 DataSet 。The Merge method is typically called at the end of a series of procedures that involve validating changes, reconciling errors, updating the data source with the changes, and finally refreshing the existing DataSet.

在客户端应用程序中，通常有一个按钮，用户可以单击该按钮来收集更改的数据并对其进行验证，然后再将其发送回中间层组件。In a client application, it is common to have a single button that the user can click that gathers the changed data and validates it before sending it back to a middle-tier component. 在此方案中， GetChanges 首先调用方法。In this scenario, the GetChanges method is first invoked. 该方法将返回第二个 DataSet 优化用于验证和合并的。That method returns a second DataSet optimized for validating and merging. 此第二个 DataSet 对象仅包含已 DataTable 更改的和 DataRow 对象，从而导致了原始的子集 DataSet 。This second DataSet object contains only the DataTable and DataRow objects that were changed, resulting in a subset of the original DataSet. 此子集通常较小，因此更有效地传递回中间层组件。This subset is generally smaller, and thus more efficiently passed back to a middle-tier component. 然后，中间层组件使用存储过程中的更改来更新原始数据源。The middle-tier component then updates the original data source with the changes through stored procedures. 然后，中间层可以 DataSet 通过再次运行原始查询来发送回包含数据源中的原始数据和最新数据 (的新数据) ，也可以从数据源向后发送回已对其进行的任何更改的子集。The middle tier can then send back either a new DataSet that includes original data and the latest data from the data source (by running the original query again), or it can send back the subset with any changes that have been made to it from the data source. (例如，如果数据源自动创建唯一的主键值，则这些值可以传播回客户端应用程序。 ) 在任何一种情况下，返回的都 DataSet 可以 DataSet 通过 Merge 方法合并回客户端应用程序的原始中。(For example, if the data source automatically creates unique primary key values, these values can be propagated back to the client application.) In either case, the returned DataSet can be merged back into the client application's original DataSet with the Merge method.

Merge调用方法时，将比较两个对象的架构， DataSet 因为架构可能已更改。When the Merge method is called, the schemas of the two DataSet objects are compared because it is possible that the schemas may have been changed. 例如，在企业对企业方案中，可能已通过自动化过程将新列添加到了 XML 架构。For example, in a business-to-business scenario, new columns may have been added to an XML schema by an automated process. 如果源 DataSet 包含架构元素 (添加了 DataColumn 目标中缺少的对象) ，则可以通过将参数设置为来将架构元素添加到目标中 missingSchemaAction MissingSchemaAction.Add 。If the source DataSet contains schema elements (added DataColumn objects) that are missing in the target, the schema elements can be added to the target by setting the missingSchemaAction argument to MissingSchemaAction.Add. 在这种情况下，合并的 DataSet 包含已添加的架构和数据。In that case, the merged DataSet contains the added schema and data.

合并架构后，数据将合并。After merging schemas, the data is merged.

在将新源合并 DataSet 到目标时，值为、或的任何源行都将与 DataRowState Unchanged Modified Deleted 具有相同的主键值的目标行匹配。When merging a new source DataSet into the target, any source rows with a DataRowState value of Unchanged, Modified, or Deleted are matched to target rows with the same primary key values. 值为的源行与新源行的 DataRowState Added 主键值相同的新目标行匹配。Source rows with a DataRowState value of Added are matched to new target rows with the same primary key values as the new source rows.

在合并过程中，将禁用约束。During a merge, constraints are disabled. 如果在合并结束时无法启用任何约束， ConstraintException 则在禁用约束时，将生成并保留合并的数据。If any constraints cannot be enabled at the end of merge, a ConstraintException is generated and the merged data is retained while the constraints are disabled. 在这种情况下， EnforceConstraints 属性设置为 false ，并且所有无效行都标记为 "错误"。In this case, the EnforceConstraints property is set to false, and all rows that are invalid are marked in error. 在尝试将属性重置为之前，必须解决这些错误 EnforceConstraints true 。The errors must be resolved before attempting to reset the EnforceConstraints property to true.

另请参阅

• ForeignKeyConstraint
• GetChanges()
• UniqueConstraint
• 在 ADO.NET 中使用数据集Using DataSets in ADO.NET

public:
 void Merge(System::Data::DataTable ^ table);

public void Merge (System.Data.DataTable table);

member this.Merge : System.Data.DataTable -> unit

Public Sub Merge (table As DataTable)

参数

例外

示例

下面的示例创建一个 DataSet 具有一个表、两列和10行的简单。The following example creates a simple DataSet with one table, two columns, and ten rows. 创建的第二个与 DataTable 第一个相同。A second DataTable is created that is identical to the first. 向第二个表添加两行，然后将其合并到中 DataSet 。Two rows are added to the second table, which is then merged into the DataSet.

private void DemonstrateMergeTable()
{
    // Create a DataSet with one table, two columns, and ten rows.
    DataSet dataSet = new DataSet("dataSet");
    DataTable table = new DataTable("Items");

    // Add table to the DataSet
    dataSet.Tables.Add(table);

    // Add columns
    DataColumn c1 = new DataColumn("id",
        Type.GetType("System.Int32"),"");
    DataColumn c2 = new DataColumn("Item",
        Type.GetType("System.Int32"),"");
    table.Columns.Add(c1);
    table.Columns.Add(c2);

    // DataColumn array to set primary key.
    DataColumn[] keyCol= new DataColumn[1];

    // Set primary key column.
    keyCol[0]= c1;
    table.PrimaryKey=keyCol;

    // Add a RowChanged event handler for the table.
    table.RowChanged += new
        DataRowChangeEventHandler(Row_Changed);

    // Add ten rows.
    for(int i = 0; i <10;i++)
    {
        DataRow row=table.NewRow();
        row["id"] = i;
        row["Item"]= i;
        table.Rows.Add(row);
    }
    // Accept changes.
    dataSet.AcceptChanges();

    PrintValues(dataSet, "Original values");

    // Create a second DataTable identical to the first.
    DataTable t2 = table.Clone();

    // Add three rows. Note that the id column can'te be the
    // same as existing rows in the DataSet table.
    DataRow newRow;
    newRow = t2.NewRow();
    newRow["id"] = 14;
    newRow["item"] = 774;

    //Note the alternative method for adding rows.
    t2.Rows.Add(new Object[] { 12, 555 });
    t2.Rows.Add(new Object[] { 13, 665 });

    // Merge the table into the DataSet
    Console.WriteLine("Merging");
    dataSet.Merge(t2);
    PrintValues(dataSet, "Merged With table.");
}

private void Row_Changed(object sender,
    DataRowChangeEventArgs e)
{
    Console.WriteLine("Row Changed " + e.Action.ToString()
        + "\table" + e.Row.ItemArray[0]);
}

private void PrintValues(DataSet dataSet, string label)
{
    Console.WriteLine("\n" + label);
    foreach(DataTable table in dataSet.Tables)
    {
        Console.WriteLine("TableName: " + table.TableName);
        foreach(DataRow row in table.Rows)
        {
            foreach(DataColumn column in table.Columns)
            {
                Console.Write("\table " + row[column] );
            }
            Console.WriteLine();
        }
    }
}

Private Sub DemonstrateMergeTable()
    ' Create a DataSet with one table, two columns, 
    ' and ten rows.
    Dim dataSet As New DataSet("dataSet")
    Dim table As New DataTable("Items")

    ' Add tables to the DataSet
    dataSet.Tables.Add(table)

    ' Add columns
    Dim c1 As New DataColumn("id", Type.GetType("System.Int32"), "")
    Dim c2 As New DataColumn("Item", Type.GetType("System.Int32"), "")
    table.Columns.Add(c1)
    table.Columns.Add(c2)

    ' DataColumn array to set primary key.
    Dim keyCol(0) As DataColumn

    ' Set primary key column.
    keyCol(0) = c1
    table.PrimaryKey = keyCol

    ' Add RowChanged event handler for the table.
    AddHandler table.RowChanged, AddressOf Row_Changed

    ' Add ten rows.
    Dim i As Integer
    Dim row As DataRow

    For i = 0 To 9
        row = table.NewRow()
        row("id") = i
        row("Item") = i
        table.Rows.Add(row)
    Next i

    ' Accept changes.
    dataSet.AcceptChanges()
    PrintValues(dataSet, "Original values")

    ' Create a second DataTable identical to the first.
    Dim t2 As DataTable
    t2 = table.Clone()

    ' Add three rows. Note that the id column can't be the 
    ' same as existing rows in the DataSet table.
    Dim newRow As DataRow
    newRow = t2.NewRow()
    newRow("id") = 14
    newRow("Item") = 774
    t2.Rows.Add(newRow)

    newRow = t2.NewRow()
    newRow("id") = 12
    newRow("Item") = 555
    t2.Rows.Add(newRow)

    newRow = t2.NewRow()
    newRow("id") = 13
    newRow("Item") = 665
    t2.Rows.Add(newRow)

    ' Merge the table into the DataSet.
    Console.WriteLine("Merging")
    dataSet.Merge(t2)
    PrintValues(dataSet, "Merged With Table")
 End Sub 
     
 Private Sub Row_Changed( _
    sender As Object, e As DataRowChangeEventArgs)
     Console.WriteLine("Row Changed " & e.Action.ToString() _
        & ControlChars.Tab & e.Row.ItemArray(0).ToString())
 End Sub
 
 Private Sub PrintValues(dataSet As DataSet, label As String)
     Console.WriteLine(ControlChars.Cr & label)
     Dim table As DataTable
     Dim row As DataRow
     Dim column As DataColumn
     For Each table In  dataSet.Tables
         Console.WriteLine("TableName: " & table.TableName) 
         For Each row In  table.Rows             
             For Each column In  table.Columns
                 Console.Write(ControlChars.Tab & " " _
                    & row(column).ToString())
             Next column
             Console.WriteLine()
         Next row
     Next table
 End Sub

注解

Merge方法用于合并 DataSet 具有很大架构的两个对象。The Merge method is used to merge two DataSet objects that have largely similar schemas. 通常在客户端应用程序上使用合并，以将数据源中的最新更改合并到现有中 DataSet 。A merge is typically used on a client application to incorporate the latest changes from a data source into an existing DataSet. 这允许客户端应用程序使用 DataSet 数据源中的最新数据进行刷新。This allows the client application to have a refreshed DataSet with the latest data from the data source.

Merge方法通常在一系列过程的末尾调用，这些过程涉及验证更改、协调错误、使用更改更新数据源，最后刷新现有 DataSet 。The Merge method is typically called at the end of a series of procedures that involve validating changes, reconciling errors, updating the data source with the changes, and finally refreshing the existing DataSet.

在客户端应用程序中，通常有一个按钮，用户可以单击该按钮来收集更改的数据并对其进行验证，然后再将其发送回中间层组件。In a client application, it is common to have a single button that the user can click that gathers the changed data and validates it before sending it back to a middle-tier component. 在此方案中， GetChanges 首先调用方法。In this scenario, the GetChanges method is first invoked. 该方法将返回第二个 DataSet 优化用于验证和合并的。That method returns a second DataSet optimized for validating and merging. 此第二个 DataSet 对象仅包含已 DataTable 更改的和 DataRow 对象，从而导致了原始的子集 DataSet 。This second DataSet object contains only the DataTable and DataRow objects that were changed, resulting in a subset of the original DataSet. 此子集通常较小，因此更有效地传递回中间层组件。This subset is generally smaller, and thus more efficiently passed back to a middle-tier component. 然后，中间层组件使用存储过程中的更改来更新原始数据源。The middle-tier component then updates the original data source with the changes through stored procedures. 然后，中间层可以 DataSet 通过再次运行原始查询来发送回包含数据源中的原始数据和最新数据 (的新数据) ，也可以从数据源向后发送回已对其进行的任何更改的子集。The middle tier can then send back either a new DataSet that includes original data and the latest data from the data source (by running the original query again), or it can send back the subset with any changes that have been made to it from the data source. (例如，如果数据源自动创建唯一的主键值，则这些值可以传播回客户端应用程序。 ) 在任何一种情况下，返回的都 DataSet 可以 DataSet 通过 Merge 方法合并回客户端应用程序的原始中。(For example, if the data source automatically creates unique primary key values, these values can be propagated back to the client application.) In either case, the returned DataSet can be merged back into the client application's original DataSet with the Merge method.

Merge调用方法时，将比较两个对象的架构， DataSet 因为架构可能已更改。When the Merge method is called, the schemas of the two DataSet objects are compared because it is possible that the schemas may have been changed. 例如，在企业对企业方案中，可能已通过自动化过程将新列添加到了 XML 架构。For example, in a business-to-business scenario, new columns may have been added to an XML schema by an automated process. 如果源 DataSet 包含架构元素 (添加了 DataColumn 目标中缺少的对象) ，则可以通过将参数设置为来将架构元素添加到目标中 missingSchemaAction MissingSchemaAction.Add 。If the source DataSet contains schema elements (added DataColumn objects) that are missing in the target, the schema elements can be added to the target by setting the missingSchemaAction argument to MissingSchemaAction.Add. 在这种情况下，合并的 DataSet 包含已添加的架构和数据。In that case, the merged DataSet contains the added schema and data.

合并架构后，数据将合并。After merging schemas, the data is merged.

在将新源合并 DataSet 到目标时，值为、或的任何源行都将与 DataRowState Unchanged Modified Deleted 具有相同的主键值的目标行匹配。When merging a new source DataSet into the target, any source rows with a DataRowState value of Unchanged, Modified, or Deleted are matched to target rows with the same primary key values. 值为的源行与新源行的 DataRowState Added 主键值相同的新目标行匹配。Source rows with a DataRowState value of Added are matched to new target rows with the same primary key values as the new source rows.

在合并过程中，将禁用约束。During a merge, constraints are disabled. 如果在合并结束时无法启用任何约束， ConstraintException 则在禁用约束时，将生成并保留合并的数据。If any constraints cannot be enabled at the end of merge, a ConstraintException is generated and the merged data is retained while the constraints are disabled. 在这种情况下， EnforceConstraints 属性设置为 false ，并且所有无效行都标记为 "错误"。In this case, the EnforceConstraints property is set to false, and all rows that are invalid are marked in error. 在尝试将属性重置为之前，必须解决这些错误 EnforceConstraints true 。The errors must be resolved before attempting to reset the EnforceConstraints property to true.

另请参阅

• 在 ADO.NET 中使用数据集Using DataSets in ADO.NET

public:
 void Merge(System::Data::DataSet ^ dataSet, bool preserveChanges);

public void Merge (System.Data.DataSet dataSet, bool preserveChanges);

member this.Merge : System.Data.DataSet * bool -> unit

Public Sub Merge (dataSet As DataSet, preserveChanges As Boolean)

参数

示例

下面的示例创建一个 DataSet 具有一个表、两列和10行的简单。The following example creates a simple DataSet with one table, two columns, and ten rows. 添加10行后，将更改两个值，并添加一行。After adding ten rows, two values are changed, and one row is added. 使用方法创建更改的数据的子集 GetChanges 。A subset of the changed data is created using the GetChanges method. 在协调错误后，将子集数据合并到原始中 DataSet 。After reconciling errors, the subset data is merged into the original DataSet.

private void DemonstrateMerge()
{
    // Create a DataSet with one table, two columns,
    // and three rows.
    DataSet dataSet = new DataSet("dataSet");
    DataTable table = new DataTable("Items");
    DataColumn idColumn = new DataColumn("id",
        Type.GetType("System.Int32"),"");
    idColumn.AutoIncrement=true;
    DataColumn itemColumn = new DataColumn("Item",
        Type.GetType("System.Int32"),"");

    // DataColumn array to set primary key.
    DataColumn[] keyColumn= new DataColumn[1];
    DataRow row;

    // Create variable for temporary DataSet.
    DataSet changesDataSet;

    // Add RowChanged event handler for the table.
    table.RowChanged+=new DataRowChangeEventHandler(
        Row_Changed);
    dataSet.Tables.Add(table);
    table.Columns.Add(idColumn);
    table.Columns.Add(itemColumn);

    // Set primary key column.
    keyColumn[0]= idColumn;
    table.PrimaryKey=keyColumn;
    // Add ten rows.
    for(int i = 0; i <10;i++)
    {
        row=table.NewRow();
        row["Item"]= i;
        table.Rows.Add(row);
    }
    // Accept changes.
    dataSet.AcceptChanges();
    PrintValues(dataSet, "Original values");

    // Change row values.
    table.Rows[0]["Item"]= 50;
    table.Rows[1]["Item"]= 111;

    // Add one row.
    row=table.NewRow();
    row["Item"]=74;
    table.Rows.Add(row);

    // Insert code for error checking. Set one row in error.
    table.Rows[1].RowError= "over 100";
    PrintValues(dataSet, "Modified and New Values");

    // If the table has changes or errors,
    // create a subset DataSet.
    if(dataSet.HasChanges(DataRowState.Modified |
        DataRowState.Added)&& dataSet.HasErrors)
    {
        // Use GetChanges to extract subset.
        changesDataSet = dataSet.GetChanges(
            DataRowState.Modified|DataRowState.Added);
        PrintValues(changesDataSet, "Subset values");

        // Insert code to reconcile errors. In this case, reject changes.
        foreach(DataTable changesTable in changesDataSet.Tables)
        {
            if (changesTable.HasErrors)
            {
                foreach(DataRow changesRow in changesTable.Rows)
                {
                    //Console.WriteLine(changesRow["Item"]);
                    if((int)changesRow["Item",DataRowVersion.Current ]> 100)
                    {
                        changesRow.RejectChanges();
                        changesRow.ClearErrors();
                    }
                }
            }
        }
        // Add a column to the changesDataSet.
        changesDataSet.Tables["Items"].Columns.Add(
            new DataColumn("newColumn"));
        PrintValues(changesDataSet, "Reconciled subset values");
        // Merge changes back to first DataSet.
        dataSet.Merge(changesDataSet, false,
            System.Data.MissingSchemaAction.Add);
    }
    PrintValues(dataSet, "Merged Values");
}

private void Row_Changed(object sender, DataRowChangeEventArgs e)
{
    Console.WriteLine("Row Changed " + e.Action.ToString()
        + "\table" + e.Row.ItemArray[0]);
}

private void PrintValues(DataSet dataSet, string label)
{
    Console.WriteLine(label + "\n");
    foreach(DataTable table in dataSet.Tables)
    {
        Console.WriteLine("TableName: " + table.TableName);
        foreach(DataRow row in table.Rows)
        {
            foreach(DataColumn column in table.Columns)
            {
                Console.Write("\table " + row[column] );
            }
            Console.WriteLine();
        }
    }
}

Private Sub DemonstrateMerge()
    ' Create a DataSet with one table, two columns, 
    ' and three rows.
    Dim dataSet As New DataSet("dataSet")
    Dim table As New DataTable("Items")
    Dim idColumn As New DataColumn("id", _
        Type.GetType("System.Int32"), "")
    idColumn.AutoIncrement = True
    Dim itemColumn As New DataColumn("Item", _
        Type.GetType("System.Int32"), "")

    ' Create DataColumn array to set primary key.
    Dim keyColumn(0) As DataColumn
    Dim row As DataRow

    ' Create variable for temporary DataSet. 
    Dim changesDataSet As DataSet

    ' Add RowChanged event handler for the table.
    AddHandler table.RowChanged, AddressOf Row_Changed
    dataSet.Tables.Add(table)
    table.Columns.Add(idColumn)
    table.Columns.Add(itemColumn)

    ' Set primary key column.
    keyColumn(0) = idColumn
    table.PrimaryKey = keyColumn

    ' Add ten rows.
    Dim i As Integer
    For i = 0 To 9
        row = table.NewRow()
        row("Item") = i
        table.Rows.Add(row)
    Next i

    ' Accept changes.
    dataSet.AcceptChanges()
    PrintValues(dataSet, "Original values")

    ' Change row values.
    table.Rows(0)("Item") = 50
    table.Rows(1)("Item") = 111

    ' Add one row.
    row = table.NewRow()
    row("Item") = 74
    table.Rows.Add(row)

    ' Insert code for error checking. Set one row in error.
    table.Rows(1).RowError = "over 100"
    PrintValues(dataSet, "Modified and New Values")

    ' If the table has changes or errors, create a subset DataSet.
    If dataSet.HasChanges(DataRowState.Modified Or DataRowState.Added) _
        And dataSet.HasErrors Then
        ' Use GetChanges to extract subset.
        changesDataSet = dataSet.GetChanges( _
            DataRowState.Modified Or DataRowState.Added)
        PrintValues(changesDataSet, "Subset values")

        ' Insert code to reconcile errors. In this case, reject changes.
        Dim changesTable As DataTable
        For Each changesTable In  changesDataSet.Tables
            If changesTable.HasErrors Then
                Dim changesRow As DataRow
                For Each changesRow In  changesTable.Rows
                    'Console.WriteLine(changesRow["Item"]);
                    If CInt(changesRow("Item", _
                        DataRowVersion.Current)) > 100 Then
                        changesRow.RejectChanges()
                        changesRow.ClearErrors()
                    End If
                Next changesRow
            End If
        Next changesTable

        ' Add a column to the changesDataSet.
        changesDataSet.Tables("Items").Columns.Add( _
            New DataColumn("newColumn"))
        PrintValues(changesDataSet, "Reconciled subset values")

        ' Merge changes back to first DataSet.
        dataSet.Merge(changesDataSet, False, _
            System.Data.MissingSchemaAction.Add)
    End If
    PrintValues(dataSet, "Merged Values")
End Sub
        
 Private Sub Row_Changed(sender As Object, e As DataRowChangeEventArgs)
     Console.WriteLine("Row Changed " + e.Action.ToString() _
        + ControlChars.Tab + e.Row.ItemArray(0).ToString())
 End Sub
    
Private Sub PrintValues(dataSet As DataSet, label As String)
     Console.WriteLine(label + ControlChars.Cr)
     Dim table As DataTable
     For Each table In  dataSet.Tables
         Console.WriteLine("TableName: " + table.TableName)
         Dim row As DataRow
         For Each row In  table.Rows
             Dim column As DataColumn
             For Each column In  table.Columns
                 Console.Write(ControlChars.Tab & " " _
                    & row(column).ToString())
             Next column
             Console.WriteLine()
         Next row
     Next table
End Sub

注解

Merge方法用于合并 DataSet 具有很大架构的两个对象。The Merge method is used to merge two DataSet objects that have largely similar schemas. 通常在客户端应用程序上使用合并，以将数据源中的最新更改合并到现有中 DataSet 。A merge is typically used on a client application to incorporate the latest changes from a data source into an existing DataSet. 这允许客户端应用程序使用 DataSet 数据源中的最新数据进行刷新。This allows the client application to have a refreshed DataSet with the latest data from the data source.

Merge方法通常在一系列过程的末尾调用，这些过程涉及验证更改、协调错误、使用更改更新数据源，最后刷新现有 DataSet 。The Merge method is typically called at the end of a series of procedures that involve validating changes, reconciling errors, updating the data source with the changes, and finally refreshing the existing DataSet.

在客户端应用程序中，通常有一个按钮，用户可以单击该按钮来收集更改的数据并对其进行验证，然后再将其发送回中间层组件。In a client application, it is common to have a single button that the user can click that gathers the changed data and validates it before sending it back to a middle-tier component. 在此方案中， GetChanges 首先调用方法。In this scenario, the GetChanges method is first invoked. 该方法将返回第二个 DataSet 优化用于验证和合并的。That method returns a second DataSet optimized for validating and merging. 此第二个 DataSet 对象仅包含已 DataTable 更改的和 DataRow 对象，从而导致了原始的子集 DataSet 。This second DataSet object contains only the DataTable and DataRow objects that were changed, resulting in a subset of the original DataSet. 此子集通常较小，因此更有效地传递回中间层组件。This subset is generally smaller, and thus more efficiently passed back to a middle-tier component. 然后，中间层组件使用存储过程中的更改来更新原始数据源。The middle-tier component then updates the original data source with the changes through stored procedures. 然后，中间层可以 DataSet 通过再次运行原始查询来发送回包含数据源中的原始数据和最新数据 (的新数据) ，也可以从数据源向后发送回已对其进行的任何更改的子集。The middle tier can then send back either a new DataSet that includes original data and the latest data from the data source (by running the original query again), or it can send back the subset with any changes that have been made to it from the data source. (例如，如果数据源自动创建唯一的主键值，则这些值可以传播回客户端应用程序。 ) 在任何一种情况下，返回的都 DataSet 可以 DataSet 通过 Merge 方法合并回客户端应用程序的原始中。(For example, if the data source automatically creates unique primary key values, these values can be propagated back to the client application.) In either case, the returned DataSet can be merged back into the client application's original DataSet with the Merge method.

Merge调用方法时，将比较两个对象的架构， DataSet 因为架构可能已更改。When the Merge method is called, the schemas of the two DataSet objects are compared because it is possible that the schemas may have been changed. 例如，在企业对企业方案中，可能已通过自动化过程将新列添加到了 XML 架构。For example, in a business-to-business scenario, new columns may have been added to an XML schema by an automated process. 如果源 DataSet 包含架构元素 (添加了 DataColumn 目标中缺少的对象) ，则可以通过将参数设置为来将架构元素添加到目标中 missingSchemaAction MissingSchemaAction.Add 。If the source DataSet contains schema elements (added DataColumn objects) that are missing in the target, the schema elements can be added to the target by setting the missingSchemaAction argument to MissingSchemaAction.Add. 在这种情况下，合并的 DataSet 包含已添加的架构和数据。In that case, the merged DataSet contains the added schema and data.

合并架构后，数据将合并。After merging schemas, the data is merged.

在将新源合并 DataSet 到目标时，值为、或的任何源行都将与 DataRowState Unchanged Modified Deleted 具有相同的主键值的目标行匹配。When merging a new source DataSet into the target, any source rows with a DataRowState value of Unchanged, Modified, or Deleted are matched to target rows with the same primary key values. 值为的源行与新源行的 DataRowState Added 主键值相同的新目标行匹配。Source rows with a DataRowState value of Added are matched to new target rows with the same primary key values as the new source rows.

在合并过程中，将禁用约束。During a merge, constraints are disabled. 如果在合并结束时无法启用任何约束， ConstraintException 则在禁用约束时，将生成并保留合并的数据。If any constraints cannot be enabled at the end of merge, a ConstraintException is generated and the merged data is retained while the constraints are disabled. 在这种情况下， EnforceConstraints 属性设置为 false ，并且所有无效行都标记为 "错误"。In this case, the EnforceConstraints property is set to false, and all rows that are invalid are marked in error. 在尝试将属性重置为之前，必须解决这些错误 EnforceConstraints true 。The errors must be resolved before attempting to reset the EnforceConstraints property to true.

另请参阅

• ForeignKeyConstraint
• UniqueConstraint
• 在 ADO.NET 中使用数据集Using DataSets in ADO.NET

public:
 void Merge(cli::array <System::Data::DataRow ^> ^ rows, bool preserveChanges, System::Data::MissingSchemaAction missingSchemaAction);

public void Merge (System.Data.DataRow[] rows, bool preserveChanges, System.Data.MissingSchemaAction missingSchemaAction);

member this.Merge : System.Data.DataRow[] * bool * System.Data.MissingSchemaAction -> unit

Public Sub Merge (rows As DataRow(), preserveChanges As Boolean, missingSchemaAction As MissingSchemaAction)

参数

注解

Merge方法用于合并 DataSet 具有很大架构的两个对象。The Merge method is used to merge two DataSet objects that have largely similar schemas. 通常在客户端应用程序上使用合并，以将数据源中的最新更改合并到现有中 DataSet 。A merge is typically used on a client application to incorporate the latest changes from a data source into an existing DataSet. 这允许客户端应用程序使用 DataSet 数据源中的最新数据进行刷新。This allows the client application to have a refreshed DataSet with the latest data from the data source.

Merge方法通常在一系列过程的末尾调用，这些过程涉及验证更改、协调错误、使用更改更新数据源，最后刷新现有 DataSet 。The Merge method is typically called at the end of a series of procedures that involve validating changes, reconciling errors, updating the data source with the changes, and finally refreshing the existing DataSet.

在客户端应用程序中，通常有一个按钮，用户可以单击该按钮来收集更改的数据并对其进行验证，然后再将其发送回中间层组件。In a client application, it is common to have a single button that the user can click that gathers the changed data and validates it before sending it back to a middle-tier component. 在此方案中， GetChanges 首先调用方法。In this scenario, the GetChanges method is first invoked. 该方法将返回第二个 DataSet 优化用于验证和合并的。That method returns a second DataSet optimized for validating and merging. 此第二个 DataSet 对象仅包含已 DataTable 更改的和 DataRow 对象，从而导致了原始的子集 DataSet 。This second DataSet object contains only the DataTable and DataRow objects that were changed, resulting in a subset of the original DataSet. 此子集通常较小，因此更有效地传递回中间层组件。This subset is generally smaller, and thus more efficiently passed back to a middle-tier component. 然后，中间层组件使用存储过程中的更改来更新原始数据源。The middle-tier component then updates the original data source with the changes through stored procedures. 然后，中间层可以 DataSet 通过再次运行原始查询来发送回包含数据源中的原始数据和最新数据 (的新数据) ，也可以从数据源向后发送回已对其进行的任何更改的子集。The middle tier can then send back either a new DataSet that includes original data and the latest data from the data source (by running the original query again), or it can send back the subset with any changes that have been made to it from the data source. (例如，如果数据源自动创建唯一的主键值，则这些值可以传播回客户端应用程序。 ) 在任何一种情况下，返回的都 DataSet 可以 DataSet 通过 Merge 方法合并回客户端应用程序的原始中。(For example, if the data source automatically creates unique primary key values, these values can be propagated back to the client application.) In either case, the returned DataSet can be merged back into the client application's original DataSet with the Merge method.

为了便于解释 Merge 方法，我们使用 "目标" 来表示当前 DataSet ，将 "source" 命名为第二个 (参数) DataSet 。To facilitate explanation of the Merge method, we use "target" to signify the current DataSet, and "source" to name the second (parameter) DataSet. 由于目标是在其上 DataSet 执行合并) 操作 (的对象，因此命名为。The target DataSet is so named because it is the object upon which an action (the merge) occurs. 第二个 DataSet 称为 "源"，因为它包含的信息不会更改，而是合并到当前中 DataSet 。The second DataSet is called a "source" because the information it contains does not change, but instead is merged into the current DataSet.

Merge调用方法时，将比较两个对象的架构， DataSet 因为架构可能已更改。When the Merge method is called, the schemas of the two DataSet objects are compared because it is possible that the schemas may have been changed. 例如，在企业对企业方案中，可能已通过自动化过程将新列添加到了 XML 架构。For example, in a business-to-business scenario, new columns may have been added to an XML schema by an automated process. 如果源 DataSet 包含架构元素 (添加了 DataColumn 目标中缺少的对象) ，则可以通过将参数设置为来将架构元素添加到目标中 missingSchemaAction MissingSchemaAction.Add 。If the source DataSet contains schema elements (added DataColumn objects) that are missing in the target, the schema elements can be added to the target by setting the missingSchemaAction argument to MissingSchemaAction.Add. 在这种情况下，合并的 DataSet 包含已添加的架构和数据。In that case, the merged DataSet contains the added schema and data.

合并架构后，数据将合并。After merging schemas, the data is merged.

在将新源合并 DataSet 到目标时，值为、或的任何源行都将与 DataRowState Unchanged Modified Deleted 具有相同的主键值的目标行匹配。When merging a new source DataSet into the target, any source rows with a DataRowState value of Unchanged, Modified, or Deleted are matched to target rows with the same primary key values. 值为的源行与新源行的 DataRowState Added 主键值相同的新目标行匹配。Source rows with a DataRowState value of Added are matched to new target rows with the same primary key values as the new source rows.

在合并过程中，将禁用约束。During a merge, constraints are disabled. 如果在合并结束时无法启用任何约束， ConstraintException 则在禁用约束时，将生成并保留合并的数据。If any constraints cannot be enabled at the end of merge, a ConstraintException is generated and the merged data is retained while the constraints are disabled. 在这种情况下， EnforceConstraints 属性设置为 false ，并且所有无效行都标记为 "错误"。In this case, the EnforceConstraints property is set to false, and all rows that are invalid are marked in error. 在尝试将属性重置为之前，必须解决这些错误 EnforceConstraints true 。The errors must be resolved before attempting to reset the EnforceConstraints property to true.

另请参阅

• 在 ADO.NET 中使用数据集Using DataSets in ADO.NET

public:
 void Merge(System::Data::DataSet ^ dataSet, bool preserveChanges, System::Data::MissingSchemaAction missingSchemaAction);

public void Merge (System.Data.DataSet dataSet, bool preserveChanges, System.Data.MissingSchemaAction missingSchemaAction);

member this.Merge : System.Data.DataSet * bool * System.Data.MissingSchemaAction -> unit

Public Sub Merge (dataSet As DataSet, preserveChanges As Boolean, missingSchemaAction As MissingSchemaAction)

参数

例外

示例

下面的示例创建一个 DataSet 具有一个表、两列和10行的简单。The following example creates a simple DataSet with one table, two columns, and ten rows. 更改了两个值，并添加了一行。Two values are changed, and one row is added. 使用方法创建更改的数据的子集 GetChanges 。A subset of the changed data is created using the GetChanges method. 在协调错误后，会将一个新列添加到子集，从而更改架构。After reconciling errors, a new column is added to the subset, changing the schema. 在 Merge 将设置为的情况下调用方法时 missingSchemaAction MissingSchemaAction.Add ，会将新列添加到原始 DataSet 对象的架构。When the Merge method is called with the missingSchemaAction set to MissingSchemaAction.Add, the new column is added to the original DataSet object's schema.

private void DemonstrateMergeMissingSchema()
{
    // Create a DataSet with one table, two columns,
    // and three rows.
    DataSet dataSet = new DataSet("dataSet");
    DataTable table = new DataTable("Items");
    DataColumn idColumn = new DataColumn("id",
        Type.GetType("System.Int32"));
    idColumn.AutoIncrement=true;
    DataColumn itemColumn = new DataColumn("Item",
        Type.GetType("System.Int32"));
    // DataColumn array to set primary key.

    DataColumn[] keyColumn= new DataColumn[1];
    DataRow row;
    // Create variable for temporary DataSet.
    DataSet changeDataSet;

    // Add RowChanged event handler for the table.
    table.RowChanged+= new DataRowChangeEventHandler(
        Row_Changed);
    dataSet.Tables.Add(table);
    table.Columns.Add(idColumn);
    table.Columns.Add(itemColumn);

    // Set primary key column.
    keyColumn[0]= idColumn;
    table.PrimaryKey=keyColumn;

    // Add ten rows.
    for(int i = 0; i <10;i++)
    {
        row=table.NewRow();
        row["Item"]= i;
        table.Rows.Add(row);
    }

    // Accept changes.
    dataSet.AcceptChanges();
    PrintValues(dataSet, "Original values");

    // Change row values.
    table.Rows[0]["Item"]= 50;
    table.Rows[1]["Item"]= 111;

    // Add one row.
    row=table.NewRow();
    row["Item"]=74;
    table.Rows.Add(row);

    // Insert code for error checking. Set one row in error.
    table.Rows[1].RowError= "over 100";
    PrintValues(dataSet, "Modified and New Values");
    // If the table has changes or errors, create a subset DataSet.
    if(dataSet.HasChanges(DataRowState.Modified |
        DataRowState.Added)& dataSet.HasErrors)
    {
        // Use GetChanges to extract subset.
        changeDataSet = dataSet.GetChanges(
            DataRowState.Modified|DataRowState.Added);
        PrintValues(changeDataSet, "Subset values");

        // Insert code to reconcile errors. Reject the changes.
        foreach(DataTable changeTable in changeDataSet.Tables)
        {
            if (changeTable.HasErrors)
            {
                foreach(DataRow changeRow in changeTable.Rows)
                {
                    //Console.WriteLine(changeRow["Item"]);
                    if((int)changeRow["Item",
                        DataRowVersion.Current ]> 100)
                    {
                        changeRow.RejectChanges();
                        changeRow.ClearErrors();
                    }
                }
            }
        }
        // Add a column to the changeDataSet to change the schema.
        changeDataSet.Tables["Items"].Columns.Add(
            new DataColumn("newColumn"));
        PrintValues(changeDataSet, "Reconciled subset values");

        // Add values to the rows for each column.
        foreach(DataRow rowItem in changeDataSet.Tables["Items"].Rows)
        {
            rowItem["newColumn"] = "my new schema value";
        }
        // Merge changes back to first DataSet.
        dataSet.Merge(changeDataSet, false,
            System.Data.MissingSchemaAction.Add);
    }
    PrintValues(dataSet, "Merged Values");
}

private void Row_Changed(object sender, DataRowChangeEventArgs e)
{
    Console.WriteLine("Row Changed " + e.Action.ToString()
        + "\table" + e.Row.ItemArray[0]);
}

private void PrintValues(DataSet dataSet, string label)
{
    Console.WriteLine("\n" + label);
    foreach(DataTable table in dataSet.Tables)
    {
        Console.WriteLine("TableName: " + table.TableName);
        foreach(DataRow row in table.Rows)
        {
            foreach(DataColumn column in table.Columns)
            {
                Console.Write("\table " + row[column] );
            }
            Console.WriteLine();
        }
    }
}

Private Sub DemonstrateMergeMissingSchema()
    ' Create a DataSet with one table, two columns, 
    ' and three rows.
    Dim dataSet As New DataSet("dataSet")
    Dim table As New DataTable("Items")
    Dim idColumn As New DataColumn("id", _
        Type.GetType("System.Int32"))
    idColumn.AutoIncrement = True
    Dim itemColumn As New DataColumn("Item", _
        Type.GetType("System.Int32"))

    ' DataColumn array to set primary key.
    Dim keyColumn(0) As DataColumn
    Dim row As DataRow

    ' Create variable for temporary DataSet. 
    Dim changeDataSet As DataSet

    ' Add RowChanged event handler for the table.
    AddHandler table.RowChanged, AddressOf Row_Changed
    dataSet.Tables.Add(table)
    table.Columns.Add(idColumn)
    table.Columns.Add(itemColumn)

    ' Set primary key column.
    keyColumn(0) = idColumn
    table.PrimaryKey = keyColumn

    ' Add ten rows.
    Dim i As Integer
    For i = 0 To 9
        row = table.NewRow()
        row("Item") = i
        table.Rows.Add(row)
    Next i

    ' Accept changes.
    dataSet.AcceptChanges()
    PrintValues(dataSet, "Original values")

    ' Change row values.
    table.Rows(0)("Item") = 50
    table.Rows(1)("Item") = 111

    ' Add one row.
    row = table.NewRow()
    row("Item") = 74
    table.Rows.Add(row)

    ' Insert code for error checking. Set one row in error.
    table.Rows(1).RowError = "over 100"
    PrintValues(dataSet, "Modified and New Values")
    ' If the table has changes or errors, 
    ' create a subset DataSet.
    If dataSet.HasChanges(DataRowState.Modified Or DataRowState.Added) _
        And dataSet.HasErrors Then
        ' Use GetChanges to extract subset.
        changeDataSet = dataSet.GetChanges(DataRowState.Modified _
            Or DataRowState.Added)
        PrintValues(changeDataSet, "Subset values")
        ' Insert code to reconcile errors. In this case, reject changes.
        Dim changeTable As DataTable
        For Each changeTable In  changeDataSet.Tables
            If changeTable.HasErrors Then
                Dim changeRow As DataRow
                For Each changeRow In  changeTable.Rows
                    If CInt(changeRow("Item", _
                        DataRowVersion.Current)) > 100 Then
                        changeRow.RejectChanges()
                        changeRow.ClearErrors()
                    End If
                Next changeRow
            End If
        Next changeTable

        ' Add a column to the changeDataSet to change the schema.
        changeDataSet.Tables("Items").Columns.Add( _
            New DataColumn("newColumn"))
        PrintValues(changeDataSet, "Reconciled subset values")

        ' Add values to the rows for each column.
        Dim rowItem As DataRow
        For Each rowItem In  changeDataSet.Tables("Items").Rows
            rowItem("newColumn") = "my new schema value"
        Next rowItem

        ' Merge changes back to first DataSet.
        dataSet.Merge(changeDataSet, False, _
            System.Data.MissingSchemaAction.Add)
    End If
    PrintValues(dataSet, "Merged Values")
End Sub
    
Private Sub Row_Changed(sender As Object, _
    e As DataRowChangeEventArgs)
     Console.WriteLine("Row Changed " & e.Action.ToString() _
        & ControlChars.Tab & e.Row.ItemArray(0).ToString())
End Sub
 
Private Sub PrintValues(dataSet As DataSet, label As String)
    Console.WriteLine(ControlChars.Cr & label)
    Dim table As DataTable
    For Each table In  dataSet.Tables
        Console.WriteLine("TableName: " & table.TableName)
        Dim row As DataRow
        For Each row In  table.Rows
            Dim column As DataColumn
            For Each column In  table.Columns
                Console.Write(ControlChars.Tab & " " _
                    & row(column).ToString())
            Next column
            Console.WriteLine()
        Next row
    Next table
End Sub

注解

Merge方法用于合并 DataSet 具有很大架构的两个对象。The Merge method is used to merge two DataSet objects that have largely similar schemas. 通常在客户端应用程序上使用合并，以将数据源中的最新更改合并到现有中 DataSet 。A merge is typically used on a client application to incorporate the latest changes from a data source into an existing DataSet. 这允许客户端应用程序使用 DataSet 数据源中的最新数据进行刷新。This allows the client application to have a refreshed DataSet with the latest data from the data source.

Merge方法通常在一系列过程的末尾调用，这些过程涉及验证更改、协调错误、使用更改更新数据源，最后刷新现有 DataSet 。The Merge method is typically called at the end of a series of procedures that involve validating changes, reconciling errors, updating the data source with the changes, and finally refreshing the existing DataSet.

在客户端应用程序中，通常有一个按钮，用户可以单击该按钮来收集更改的数据并对其进行验证，然后再将其发送回中间层组件。In a client application, it is common to have a single button that the user can click that gathers the changed data and validates it before sending it back to a middle-tier component. 在此方案中， GetChanges 首先调用方法。In this scenario, the GetChanges method is first invoked. 该方法将返回第二个 DataSet 优化用于验证和合并的。That method returns a second DataSet optimized for validating and merging. 此第二个 DataSet 对象仅包含已 DataTable 更改的和 DataRow 对象，从而导致了原始的子集 DataSet 。This second DataSet object contains only the DataTable and DataRow objects that were changed, resulting in a subset of the original DataSet. 此子集通常较小，因此更有效地传递回中间层组件。This subset is generally smaller, and thus more efficiently passed back to a middle-tier component. 然后，中间层组件使用存储过程中的更改来更新原始数据源。The middle-tier component then updates the original data source with the changes through stored procedures. 然后，中间层可以 DataSet 通过再次运行原始查询来发送回包含数据源中的原始数据和最新数据 (的新数据) ，也可以从数据源向后发送回已对其进行的任何更改的子集。The middle tier can then send back either a new DataSet that includes original data and the latest data from the data source (by running the original query again), or it can send back the subset with any changes that have been made to it from the data source. (例如，如果数据源自动创建唯一的主键值，则这些值可以传播回客户端应用程序。 ) 在任何一种情况下，返回的都 DataSet 可以 DataSet 通过 Merge 方法合并回客户端应用程序的原始中。(For example, if the data source automatically creates unique primary key values, these values can be propagated back to the client application.) In either case, the returned DataSet can be merged back into the client application's original DataSet with the Merge method.

为了便于解释 Merge 方法，我们使用 "目标" 来表示当前 DataSet ，将 "source" 命名为第二个 (参数) DataSet 。To facilitate explanation of the Merge method, we use "target" to signify the current DataSet, and "source" to name the second (parameter) DataSet. 由于目标是在其上 DataSet 执行合并) 操作 (的对象，因此命名为。The target DataSet is so named because it is the object upon which an action (the merge) occurs. 第二个 DataSet 称为 "源"，因为它包含的信息不会更改，而是合并到当前中 DataSet 。The second DataSet is called a "source" because the information it contains does not change, but instead is merged into the current DataSet.

Merge调用方法时，将比较两个对象的架构， DataSet 因为架构可能已更改。When the Merge method is called, the schemas of the two DataSet objects are compared because it is possible that the schemas may have been changed. 例如，在企业对企业方案中，可能已通过自动化过程将新列添加到了 XML 架构。For example, in a business-to-business scenario, new columns may have been added to an XML schema by an automated process. 如果源 DataSet 包含架构元素 (添加了 DataColumn 目标中缺少的对象) ，则可以通过将参数设置为来将架构元素添加到目标中 missingSchemaAction MissingSchemaAction.Add 。If the source DataSet contains schema elements (added DataColumn objects) that are missing in the target, the schema elements can be added to the target by setting the missingSchemaAction argument to MissingSchemaAction.Add. 在这种情况下，合并的 DataSet 包含已添加的架构和数据。In that case, the merged DataSet contains the added schema and data.

合并架构后，数据将合并。After merging schemas, the data is merged.

在将新源合并 DataSet 到目标时，值为、或的任何源行都将与 DataRowState Unchanged Modified Deleted 具有相同的主键值的目标行匹配。When merging a new source DataSet into the target, any source rows with a DataRowState value of Unchanged, Modified, or Deleted are matched to target rows with the same primary key values. 值为的源行与新源行的 DataRowState Added 主键值相同的新目标行匹配。Source rows with a DataRowState value of Added are matched to new target rows with the same primary key values as the new source rows.

在合并过程中，将禁用约束。During a merge, constraints are disabled. 如果在合并结束时无法启用任何约束， ConstraintException 则在禁用约束时，将生成并保留合并的数据。If any constraints cannot be enabled at the end of merge, a ConstraintException is generated and the merged data is retained while the constraints are disabled. 在这种情况下， EnforceConstraints 属性设置为 false ，并且所有无效行都标记为 "错误"。In this case, the EnforceConstraints property is set to false, and all rows that are invalid are marked in error. 在尝试将属性重置为之前，必须解决这些错误 EnforceConstraints true 。The errors must be resolved before attempting to reset the EnforceConstraints property to true.

另请参阅

• 在 ADO.NET 中使用数据集Using DataSets in ADO.NET

public:
 void Merge(System::Data::DataTable ^ table, bool preserveChanges, System::Data::MissingSchemaAction missingSchemaAction);

public void Merge (System.Data.DataTable table, bool preserveChanges, System.Data.MissingSchemaAction missingSchemaAction);

member this.Merge : System.Data.DataTable * bool * System.Data.MissingSchemaAction -> unit

Public Sub Merge (table As DataTable, preserveChanges As Boolean, missingSchemaAction As MissingSchemaAction)

参数

例外

示例

下面的示例创建一个 DataSet 具有一个表、两列和10行的简单。The following example creates a simple DataSet with one table, two columns, and ten rows. 创建的第二个与 DataTable 第一个完全相同，只是向表中添加了一个新的 DataColumn 。A second DataTable is created that is nearly identical to the first except that a new DataColumn is added to the table. 向第二个表中添加了两行，然后将其合并到中 DataSet preserveChanges ，并将参数设置为 false ，并将 missingSchemaAction 参数设置为 MissingSchemaAction.Add 。Two rows are added to the second table, which is then merged into the DataSet with the preserveChanges argument set to false, and the missingSchemaAction argument set to MissingSchemaAction.Add.

private void DemonstrateMergeTableAddSchema()
{
    // Create a DataSet with one table, two columns, and ten rows.
    DataSet dataSet = new DataSet("dataSet");
    DataTable table = new DataTable("Items");

    // Add table to the DataSet
    dataSet.Tables.Add(table);

    // Create and add two columns to the DataTable
    DataColumn idColumn = new DataColumn("id",
        Type.GetType("System.Int32"),"");
    idColumn.AutoIncrement=true;
    DataColumn itemColumn = new DataColumn("Item",
        Type.GetType("System.Int32"),"");
    table.Columns.Add(idColumn);
    table.Columns.Add(itemColumn);

    // Set the primary key to the first column.
    table.PrimaryKey = new DataColumn[1]{ idColumn };

    // Add RowChanged event handler for the table.
    table.RowChanged+= new DataRowChangeEventHandler(Row_Changed);

    // Add ten rows.
    for(int i = 0; i <10;i++)
    {
        DataRow row=table.NewRow();
        row["Item"]= i;
        table.Rows.Add(row);
    }

    // Accept changes.
    dataSet.AcceptChanges();
    PrintValues(dataSet, "Original values");

    // Create a second DataTable identical to the first, with
    // one extra column using the Clone method.
    DataTable cloneTable = table.Clone();
    cloneTable.Columns.Add("extra", typeof(string));

    // Add two rows. Note that the id column can'table be the
    // same as existing rows in the DataSet table.
    DataRow newRow;
    newRow=cloneTable.NewRow();
    newRow["id"]= 12;
    newRow["Item"]=555;
    newRow["extra"]= "extra Column 1";
    cloneTable.Rows.Add(newRow);

    newRow=cloneTable.NewRow();
    newRow["id"]= 13;
    newRow["Item"]=665;
    newRow["extra"]= "extra Column 2";
    cloneTable.Rows.Add(newRow);

    // Merge the table into the DataSet.
    Console.WriteLine("Merging");
    dataSet.Merge(cloneTable,false,MissingSchemaAction.Add);
    PrintValues(dataSet, "Merged With Table, Schema Added");
}

private void Row_Changed(object sender,
    DataRowChangeEventArgs e)
{
    Console.WriteLine("Row Changed " + e.Action.ToString()
        + "\table" + e.Row.ItemArray[0]);
}

private void PrintValues(DataSet dataSet, string label)
{
    Console.WriteLine("\n" + label);
    foreach(DataTable table in dataSet.Tables)
    {
        Console.WriteLine("TableName: " + table.TableName);
        foreach(DataRow row in table.Rows)
        {
            foreach(DataColumn column in table.Columns)
            {
                Console.Write("\table " + row[column] );
            }
            Console.WriteLine();
        }
    }
}

Private Sub DemonstrateMergeTableAddSchema()
    ' Create a DataSet with one table, two columns, 
    'and ten rows.
    Dim dataSet As New DataSet("dataSet")
    Dim table As New DataTable("Items")

    ' Add tables to the DataSet
    dataSet.Tables.Add(table)

    ' Create and add two columns to the DataTable
    Dim idColumn As New DataColumn("id", _
        Type.GetType("System.Int32"), "")
    idColumn.AutoIncrement = True
    Dim itemColumn As New DataColumn("Item", _
        Type.GetType("System.Int32"), "")
    table.Columns.Add(idColumn)
    table.Columns.Add(itemColumn)

    ' DataColumn array to set primary key.
    Dim keyCol(0) As DataColumn

    ' Set primary key column.
    keyCol(0) = idColumn
    table.PrimaryKey = keyCol

    ' Add RowChanged event handler for the table.
    AddHandler table.RowChanged, AddressOf Row_Changed

    ' Add ten rows.
    Dim i As Integer
    Dim row As DataRow

    For i = 0 To 9
        row = table.NewRow()
        row("Item") = i
        table.Rows.Add(row)
    Next i

    ' Accept changes.
    dataSet.AcceptChanges()
    PrintValues(dataSet, "Original values")

    ' Create a second DataTable identical to the first
    ' with one extra column using the Clone method.
    Dim cloneTable As New DataTable
    cloneTable = table.Clone()

    ' Add column.
    cloneTable.Columns.Add("extra", _
        Type.GetType("System.String"))

    ' Add two rows. Note that the id column can't be the 
    ' same as existing rows in the DataSet table.
    Dim newRow As DataRow
    newRow = cloneTable.NewRow()
    newRow("id") = 12
    newRow("Item") = 555
    newRow("extra") = "extra Column 1"
    cloneTable.Rows.Add(newRow)
        
    newRow = cloneTable.NewRow()
    newRow("id") = 13
    newRow("Item") = 665
    newRow("extra") = "extra Column 2"
    cloneTable.Rows.Add(newRow)

    ' Merge the table into the DataSet.
    Console.WriteLine("Merging")
    dataSet.Merge(cloneTable, False, MissingSchemaAction.Add)
    PrintValues(dataSet, "Merged With Table, Schema Added")
End Sub
  
Private Sub Row_Changed(sender As Object, _
    e As DataRowChangeEventArgs)
    Console.WriteLine("Row Changed " & e.Action.ToString() _
        & ControlChars.Tab & e.Row.ItemArray(0).ToString())
End Sub
    
Private Sub PrintValues(dataSet As DataSet, label As String)
    Console.WriteLine(ControlChars.Cr & label)
    Dim table As DataTable
    Dim row As DataRow
    Dim column As DataColumn
    For Each table In  dataSet.Tables
        Console.WriteLine("TableName: " & table.TableName)
        For Each row In  table.Rows             
            For Each column In  table.Columns
                Console.Write(ControlChars.Tab & " " _
                    & row(column).ToString())
            Next column
            Console.WriteLine()
        Next row
    Next table
 End Sub

注解

Merge方法用于合并 DataSet 具有很大架构的两个对象。The Merge method is used to merge two DataSet objects that have largely similar schemas. 通常在客户端应用程序上使用合并，以将数据源中的最新更改合并到现有中 DataSet 。A merge is typically used on a client application to incorporate the latest changes from a data source into an existing DataSet. 这允许客户端应用程序使用 DataSet 数据源中的最新数据进行刷新。This allows the client application to have a refreshed DataSet with the latest data from the data source.

Merge方法通常在一系列过程的末尾调用，这些过程涉及验证更改、协调错误、使用更改更新数据源，最后刷新现有 DataSet 。The Merge method is typically called at the end of a series of procedures that involve validating changes, reconciling errors, updating the data source with the changes, and finally refreshing the existing DataSet.

对于客户端应用程序，通常有一个按钮，用户可以单击该按钮来收集更改的数据并对其进行验证，然后再将其发送回中间层组件。iOn a client application, it is common to have a single button that the user can click that gathers the changed data and validates it before sending it back to a middle-tier component. 在此方案中， GetChanges 首先调用方法。In this scenario, the GetChanges method is first invoked. 该方法将返回第二个 DataSet 优化用于验证和合并的。That method returns a second DataSet optimized for validating and merging. 此第二个 DataSet 对象仅包含已 DataTable 更改的和 DataRow 对象，从而导致了原始的子集 DataSet 。This second DataSet object contains only the DataTable and DataRow objects that were changed, resulting in a subset of the original DataSet. 此子集通常较小，因此更有效地传递回中间层组件。This subset is generally smaller, and thus more efficiently passed back to a middle-tier component. 然后，中间层组件使用存储过程中的更改来更新原始数据源。The middle-tier component then updates the original data source with the changes through stored procedures. 然后，中间层可以 DataSet 通过再次运行原始查询来发送回包含数据源中的原始数据和最新数据 (的新数据) ，也可以从数据源向后发送回已对其进行的任何更改的子集。The middle tier can then send back either a new DataSet that includes original data and the latest data from the data source (by running the original query again), or it can send back the subset with any changes that have been made to it from the data source. (例如，如果数据源自动创建唯一的主键值，则这些值可以传播回客户端应用程序。 ) 在任何一种情况下，返回的都 DataSet 可以 DataSet 通过 Merge 方法合并回客户端应用程序的原始中。(For example, if the data source automatically creates unique primary key values, these values can be propagated back to the client application.) In either case, the returned DataSet can be merged back into the client application's original DataSet with the Merge method.

Merge调用方法时，将比较两个对象的架构， DataSet 因为架构可能已更改。When the Merge method is called, the schemas of the two DataSet objects are compared because it is possible that the schemas may have been changed. 例如，在企业对企业方案中，可能已通过自动化过程将新列添加到了 XML 架构。For example, in a business-to-business scenario, new columns may have been added to an XML schema by an automated process. 如果源 DataSet 包含架构元素 (添加了 DataColumn 目标中缺少的对象) ，则可以通过将参数设置为来将架构元素添加到目标中 missingSchemaAction MissingSchemaAction.Add 。If the source DataSet contains schema elements (added DataColumn objects) that are missing in the target, the schema elements can be added to the target by setting the missingSchemaAction argument to MissingSchemaAction.Add. 在这种情况下，合并的 DataSet 包含已添加的架构和数据。In that case, the merged DataSet contains the added schema and data.

合并架构后，数据将合并。After merging schemas, the data is merged.

在将新源合并 DataSet 到目标时，值为、或的任何源行都将与 DataRowState Unchanged Modified Deleted 具有相同的主键值的目标行匹配。When merging a new source DataSet into the target, any source rows with a DataRowState value of Unchanged, Modified, or Deleted are matched to target rows with the same primary key values. 值为的源行与新源行的 DataRowState Added 主键值相同的新目标行匹配。Source rows with a DataRowState value of Added are matched to new target rows with the same primary key values as the new source rows.

在合并过程中，将禁用约束。During a merge, constraints are disabled. 如果在合并结束时无法启用任何约束， ConstraintException 则在禁用约束时，将生成并保留合并的数据。If any constraints cannot be enabled at the end of merge, a ConstraintException is generated and the merged data is retained while the constraints are disabled. 在这种情况下， EnforceConstraints 属性设置为 false ，并且所有无效行都标记为 "错误"。In this case, the EnforceConstraints property is set to false, and all rows that are invalid are marked in error. 在尝试将属性重置为之前，必须解决这些错误 EnforceConstraints true 。The errors must be resolved before attempting to reset the EnforceConstraints property to true.

另请参阅

• 在 ADO.NET 中使用数据集Using DataSets in ADO.NET