DataTable.RowChanging Event

Occurs when a DataRow is changing.

[Visual Basic]
Public Event RowChanging As DataRowChangeEventHandler
[C#]
public event DataRowChangeEventHandler RowChanging;
[C++]
public: __event DataRowChangeEventHandler* RowChanging;

[JScript] In JScript, you can handle the events defined by a class, but you cannot define your own.

Event Data

The event handler receives an argument of type DataRowChangeEventArgs containing data related to this event. The following DataRowChangeEventArgs properties provide information specific to this event.

Remarks

For more information see Working with DataTable Events.

Example

[Visual Basic] 
Private Shared Sub DataTableRowChanging()
    Dim custTable As DataTable = New DataTable("Customers")
    ' add columns
    custTable.Columns.Add( "id", Type.GetType("System.Int32") )
    custTable.Columns.Add( "name", Type.GetType("System.String") )
    custTable.Columns.Add( "address", Type.GetType("System.String") )

    ' set PrimaryKey
    custTable.Columns( "id" ).Unique = true
    custTable.PrimaryKey = New DataColumn() { custTable.Columns("id") }

    ' add a RowChanging event handler for the table.
    AddHandler custTable.RowChanging, New DataRowChangeEventHandler( AddressOf Row_Changing )


    ' add ten rows
    Dim id As Integer
    For id = 1 To 10
        custTable.Rows.Add( _
            New Object() { id, string.Format("customer{0}", id), string.Format("address{0}", id) } )
    Next
    
    custTable.AcceptChanges()

    ' change the name column in all the rows
    Dim row As DataRow
    For Each row In custTable.Rows 
        row("name") = string.Format( "vip{0}", row("id") )
    Next

End Sub

Private Shared Sub Row_Changing(sender As Object, e As DataRowChangeEventArgs)
    Console.WriteLine( "Row_Changing Event: name={0}; action={1}", _
        e.Row("name"), e.Action) 
End Sub

[C#] 
private static void DataTableRowChanging()
{
    DataTable custTable = new DataTable("Customers");
    // add columns
    custTable.Columns.Add( "id", typeof(int) );
    custTable.Columns.Add( "name", typeof(string) );
    custTable.Columns.Add( "address", typeof(string) );

    // set PrimaryKey
    custTable.Columns[ "id" ].Unique = true;
    custTable.PrimaryKey = new DataColumn[] { custTable.Columns["id"] };

    // add a RowChanging event handler for the table.
    custTable.RowChanging += new DataRowChangeEventHandler( Row_Changing );


    // add ten rows
    for( int id=1; id<=10; id++ )
    {
        custTable.Rows.Add( 
            new object[] { id, string.Format("customer{0}", id), string.Format("address{0}", id) } );
    }
    
    custTable.AcceptChanges();

    // change the name column in all the rows
    foreach( DataRow row in custTable.Rows )
    {
        row["name"] = string.Format( "vip{0}", row["id"] );
    }

}

private static void Row_Changing( object sender, DataRowChangeEventArgs e )
{
    Console.WriteLine( "Row_Changing Event: name={0}; action={1}", 
        e.Row["name"], e.Action );
}

[C++] 

public:
static void DataTableRowChanging() {
    DataTable* custTable = new DataTable(S"Customers");
    // add columns
    custTable->Columns->Add(S"id", __typeof(int));
    custTable->Columns->Add(S"name", __typeof(String));
    custTable->Columns->Add(S"address", __typeof(String));

    // set PrimaryKey
    custTable->Columns->Item[ S"id" ]->Unique = true;
    DataColumn* columnArray[] = { custTable->Columns->Item[S"id"] };
    custTable->PrimaryKey = columnArray;

    // add a RowChanging event handler for the table.
    custTable->RowChanging += new DataRowChangeEventHandler(0, Row_Changing);

    // add ten rows
    for (int id=1; id<=10; id++) {
        Object* temp0[] = {__box(id), String::Format(S"customer {0}", __box(id)), String::Format(S"address {0}", __box(id)) };
        custTable->Rows->Add(temp0);
    }

    custTable->AcceptChanges();

    // change the name column in all the rows
    System::Collections::IEnumerator* myEnum = custTable->Rows->GetEnumerator();
    while (myEnum->MoveNext()) {
        DataRow* row = __try_cast<DataRow*>(myEnum->Current);
        row->Item[S"name"] = String::Format(S"vip {0}", row->Item[S"id"]);
        }
};

public:
    static void Row_Changing(Object* sender, DataRowChangeEventArgs* e) {
        Console::WriteLine(S"Row_Changing Event: name= {0}; action= {1}",
        e->Row->Item[S"name"], __box(e->Action));
    };

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

DataTable Class | DataTable Members | System.Data Namespace