DataSet.HasChanges DataSet.HasChanges DataSet.HasChanges DataSet.HasChanges Method

定义

获取一个值,该值指示 DataSet 是否有更改,包括新增行、已删除的行或已修改的行。Gets a value indicating whether the DataSet has changes, including new, deleted, or modified rows.

重载

HasChanges() HasChanges() HasChanges() HasChanges()

获取一个值,该值指示 DataSet 是否有更改,包括新增行、已删除的行或已修改的行。Gets a value indicating whether the DataSet has changes, including new, deleted, or modified rows.

HasChanges(DataRowState) HasChanges(DataRowState) HasChanges(DataRowState) HasChanges(DataRowState)

获取一个值,该值指示 DataSet 是否有 DataRowState 被筛选的更改,包括新增行、已删除的行或已修改的行。Gets a value indicating whether the DataSet has changes, including new, deleted, or modified rows, filtered by DataRowState.

HasChanges() HasChanges() HasChanges() HasChanges()

获取一个值,该值指示 DataSet 是否有更改,包括新增行、已删除的行或已修改的行。Gets a value indicating whether the DataSet has changes, including new, deleted, or modified rows.

public:
 bool HasChanges();
public bool HasChanges ();
member this.HasChanges : unit -> bool
Public Function HasChanges () As Boolean

返回

如果 DataSet 有更改,则返回 true;否则,返回 falsetrue if the DataSet has changes; otherwise, false.

示例

下面的示例使用GetChanges方法来创建第二个DataSet对象,然后使用该对象更新数据源。The following example uses the GetChanges method to create a second DataSet object that is then used to update a data source.

private void UpdateDataSet(DataSet dataSet)
{
    // Check for changes with the HasChanges method first.
    if(!dataSet.HasChanges()) return;

    // Create temporary DataSet variable.
    DataSet tempDataSet;

    // GetChanges for modified rows only.
    tempDataSet = dataSet.GetChanges(DataRowState.Modified);

    // Check the DataSet for errors.
    if(tempDataSet.HasErrors)
    {
        // Insert code to resolve errors.
    }
    // After fixing errors, update the data source with 
    // the DataAdapter used to create the DataSet.
    myOleDbDataAdapter.Update(tempDataSet);
}
Private Sub UpdateDataSet(ByVal dataSet As DataSet)
    ' Check for changes with the HasChanges method first.
    If Not dataSet.HasChanges() Then 
        Exit Sub
    End If

    ' Create temporary DataSet variable.
    ' GetChanges for modified rows only.
    Dim tempDataSet As DataSet = _
        dataSet.GetChanges(DataRowState.Modified)

    ' Check the DataSet for errors.
    If tempDataSet.HasErrors Then
       ' Insert code to resolve errors.
    End If

    ' After fixing errors, update the data source with 
    ' the DataAdapter used to create the DataSet.
    myOleDbDataAdapter.Update(tempDataSet)
End Sub
另请参阅

HasChanges(DataRowState) HasChanges(DataRowState) HasChanges(DataRowState) HasChanges(DataRowState)

获取一个值,该值指示 DataSet 是否有 DataRowState 被筛选的更改,包括新增行、已删除的行或已修改的行。Gets a value indicating whether the DataSet has changes, including new, deleted, or modified rows, filtered by DataRowState.

public:
 bool HasChanges(System::Data::DataRowState rowStates);
public bool HasChanges (System.Data.DataRowState rowStates);
member this.HasChanges : System.Data.DataRowState -> bool
Public Function HasChanges (rowStates As DataRowState) As Boolean

参数

rowStates
DataRowState DataRowState DataRowState DataRowState

DataRowState 值之一。One of the DataRowState values.

返回

如果 DataSet 有更改,则返回 true;否则,返回 falsetrue if the DataSet has changes; otherwise, false.

示例

下面的示例使用GetChanges方法来创建第二个DataSet对象,然后使用该对象更新数据源。The following example uses the GetChanges method to create a second DataSet object, which is then used to update a data source.

private void UpdateDataSet(DataSet dataSet)
{
    // Check for changes with the HasChanges method first.
    if(!dataSet.HasChanges(DataRowState.Modified)) return;

    // Create temporary DataSet variable and
    // GetChanges for modified rows only.
    DataSet tempDataSet = 
        dataSet.GetChanges(DataRowState.Modified);

    // Check the DataSet for errors.
    if(tempDataSet.HasErrors)
    {
        // Insert code to resolve errors.
    }
    // After fixing errors, update the data source with  
    // the DataAdapter used to create the DataSet.
    adapter.Update(tempDataSet);
}
Private Sub UpdateDataSet(ByVal dataSet As DataSet)
   ' Check for changes with the HasChanges method first.
   If Not dataSet.HasChanges(DataRowState.Modified) Then 
       Exit Sub
   End If

   ' Create temporary DataSet variable and
   ' GetChanges for modified rows only.
   Dim tempDataSet As DataSet = _
       dataSet.GetChanges(DataRowState.Modified)

   ' Check the DataSet for errors.
   If tempDataSet.HasErrors Then
      ' Insert code to resolve errors.
   End If

   ' After fixing errors, update the data source with   
   ' the DataAdapter used to create the DataSet.
   adapter.Update(tempDataSet)
End Sub

注解

在调用DataSet HasChanges 方法之前GetChanges检查的属性。Examine the HasChanges property of the DataSet before invoking the GetChanges method.

另请参阅

适用于