DataSet.HasChanges Method

Definition

Ottiene un valore che indica se l'oggetto DataSet presenta delle modifiche, quali righe nuove, eliminate o modificate.Gets a value indicating whether the DataSet has changes, including new, deleted, or modified rows.

Overloads

HasChanges()

Ottiene un valore che indica se l'oggetto DataSet presenta delle modifiche, quali righe nuove, eliminate o modificate.Gets a value indicating whether the DataSet has changes, including new, deleted, or modified rows.

HasChanges(DataRowState)

Ottiene un valore che indica se l'oggetto DataSet presenta delle modifiche, quali righe nuove, eliminate o modificate, filtrate in base all'oggetto DataRowState.Gets a value indicating whether the DataSet has changes, including new, deleted, or modified rows, filtered by DataRowState.

HasChanges()

Ottiene un valore che indica se l'oggetto DataSet presenta delle modifiche, quali righe nuove, eliminate o modificate.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

Returns

Boolean

true se DataSet include modifiche; in caso contrario, false.true if the DataSet has changes; otherwise, false.

Examples

Nell'esempio seguente viene utilizzato il metodo GetChanges per creare un secondo oggetto DataSet che viene quindi utilizzato per aggiornare un'origine dati.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

See also

HasChanges(DataRowState)

Ottiene un valore che indica se l'oggetto DataSet presenta delle modifiche, quali righe nuove, eliminate o modificate, filtrate in base all'oggetto DataRowState.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

Parameters

rowStates
DataRowState

Uno dei valori DataRowState.One of the DataRowState values.

Returns

Boolean

true se DataSet include modifiche; in caso contrario, false.true if the DataSet has changes; otherwise, false.

Examples

Nell'esempio seguente viene utilizzato il metodo GetChanges per creare un secondo oggetto DataSet, che viene quindi utilizzato per aggiornare un'origine dati.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

Remarks

Esaminare la proprietà HasChanges della DataSet prima di richiamare il metodo di GetChanges.Examine the HasChanges property of the DataSet before invoking the GetChanges method.

See also

Applies to