DataSet.HasChanges 方法

Source:

DataSet.cs

Source:

DataSet.cs

Source:

DataSet.cs

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 false。

示例

下面的示例使用 GetChanges 方法创建第二 DataSet 个对象，然后使用该对象更新数据源。

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

• 在 ADO.NET 中使用数据集

Source:

DataSet.cs

Source:

DataSet.cs

Source:

DataSet.cs

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

返回

如果 DataSet 有更改，则返回 true；否则，返回 false。

示例

下面的示例使用 GetChanges 方法创建第二 DataSet 个 对象，然后使用该对象更新数据源。

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

HasChanges在调用 GetChanges 方法之前检查 的 DataSet 属性。

另请参阅

• 在 ADO.NET 中使用数据集