DataRowVersion 枚举

定义

介绍 DataRow 的版本。Describes the version of a DataRow.

public enum class DataRowVersion
public enum DataRowVersion
type DataRowVersion = 
Public Enum DataRowVersion
继承
DataRowVersion

字段

Current 512

包含其当前值的行。The row contains current values.

Default 1536

DataRowState 的默认版本。The default version of DataRowState. 对于 DataRowStateAddedModifiedDeleted 值,默认的版本是 CurrentFor a DataRowState value of Added, Modified or Deleted, the default version is Current. 对于 DataRowStateDetached 值,版本是 ProposedFor a DataRowState value of Detached, the version is Proposed.

Original 256

包含其原始值的行。The row contains its original values.

Proposed 1024

包含建议值的行。The row contains a proposed value.

示例

下面的示例在调用 AcceptChanges 方法之前检查 DataRowDataRowVersionThe following example checks the DataRowVersion of a DataRow before invoking the AcceptChanges method.

private static void CheckVersionBeforeAccept()
{
    //Run a function to create a DataTable with one column.
    DataTable dataTable = MakeTable();

    DataRow dataRow = dataTable.NewRow();
    dataRow["FirstName"] = "Marcy";
    dataTable.Rows.Add(dataRow);

    dataRow.BeginEdit();
    // Edit data but keep the same value.
    dataRow[0] = "Marcy";
    // Uncomment the following line to add a new value.
    // dataRow(0) = "Richard"
    Console.WriteLine(string.Format("FirstName {0}", dataRow[0]));

    // Compare the proposed version with the current.
    if (dataRow.HasVersion(DataRowVersion.Proposed)) {
        if (object.ReferenceEquals(dataRow[0, DataRowVersion.Current], dataRow[0, DataRowVersion.Proposed])) {
            Console.WriteLine("The original and the proposed are the same.");
            dataRow.CancelEdit();
        } else {
            dataRow.AcceptChanges();
            Console.WriteLine("The original and the proposed are different.");
        }
    }
}

private static DataTable MakeTable()
{
    // Make a simple table with one column.
    DataTable dt = new DataTable("dataTable");
    DataColumn firstName = new DataColumn("FirstName", Type.GetType("System.String"));
    dt.Columns.Add(firstName);
    return dt;
}
Private Sub CheckVersionBeforeAccept()
    'Run a function to create a DataTable with one column.
    Dim dataTable As DataTable = MakeTable()

    Dim dataRow As DataRow = dataTable.NewRow()
    dataRow("FirstName") = "Marcy"
    dataTable.Rows.Add(dataRow)

    dataRow.BeginEdit()
    ' Edit data but keep the same value.
    dataRow(0) = "Marcy"
    ' Uncomment the following line to add a new value.
    ' dataRow(0) = "Richard"
    Console.WriteLine(String.Format("FirstName {0}", dataRow(0)))

    ' Compare the proposed version with the current.
    If dataRow.HasVersion(DataRowVersion.Proposed) Then
        If dataRow(0, DataRowVersion.Current) Is dataRow(0, DataRowVersion.Proposed) Then
            Console.WriteLine("The original and the proposed are the same.")
            dataRow.CancelEdit()
        Else
            dataRow.AcceptChanges()
            Console.WriteLine("The original and the proposed are different.")
        End If
    End If
End Sub

Private Function MakeTable() As DataTable
    ' Make a simple table with one column.
    Dim dt As New DataTable("dataTable")
    Dim firstName As New DataColumn("FirstName", _
       Type.GetType("System.String"))
    dt.Columns.Add(firstName)
    Return dt
End Function

注解

使用 Item[String, DataRowVersion]DataRow 对象的 GetChildRows 检索 DataRow 中找到的值时,将使用 DataRowVersion 值。The DataRowVersion values are used when retrieving the value found in a DataRow using Item[String, DataRowVersion] or the GetChildRows of the DataRow object.

DataRowVersion 会通知 DataRow 存在哪个版本。The DataRowVersion informs you what version of a DataRow exists. 版本在下列情况下发生更改:Versions change under the following circumstances:

  • 调用 DataRow 对象的 BeginEdit 方法后,如果更改该值,CurrentProposed 值将变为可用。After calling the DataRow object's BeginEdit method, if you change the value, the Current and Proposed values become available.

  • 调用 DataRow 对象的 CancelEdit 方法后,将删除 Proposed 值。After calling the DataRow object's CancelEdit method, the Proposed value is deleted.

  • 调用 DataRow 对象的 EndEdit 方法后,建议的值将成为 Current 值。After calling the DataRow object's EndEdit method, the Proposed value becomes the Current value.

  • 调用 DataRow 对象的 AcceptChanges 方法后,Original 值将与 Current 值相同。After calling the DataRow object's AcceptChanges method, the Original value becomes identical to the Current value.

  • 调用 DataTable 对象的 AcceptChanges 方法后,Original 值将与 Current 值相同。After calling the DataTable object's AcceptChanges method, the Original value becomes identical to the Current value.

  • 调用 DataRow 对象的 RejectChanges 方法后,将放弃 Proposed 值,版本将变为 CurrentAfter calling the DataRow object's RejectChanges method, the Proposed value is discarded, and the version becomes Current.

适用于

另请参阅