DataTable.ColumnChanging Event

public:
 event System::Data::DataColumnChangeEventHandler ^ ColumnChanging;

public event System.Data.DataColumnChangeEventHandler? ColumnChanging;

public event System.Data.DataColumnChangeEventHandler ColumnChanging;

[System.Data.DataSysDescription("DataTableColumnChangingDescr")]
public event System.Data.DataColumnChangeEventHandler ColumnChanging;

member this.ColumnChanging : System.Data.DataColumnChangeEventHandler 

[<System.Data.DataSysDescription("DataTableColumnChangingDescr")>]
member this.ColumnChanging : System.Data.DataColumnChangeEventHandler 

Public Custom Event ColumnChanging As DataColumnChangeEventHandler 

Event Type

Attributes

DataSysDescriptionAttribute

Examples

private static void DataTableColumnChanging()
{
 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 ColumnChanging event handler for the table.
 custTable.ColumnChanging += new
 DataColumnChangeEventHandler(Column_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 Column_Changing(object sender,
 DataColumnChangeEventArgs e )
{
 Console.WriteLine(
 "Column_Changing Event: name={0}; Column={1}; proposed name={2}",
 e.Row["name"], e.Column.ColumnName, e.ProposedValue );
}

Private Shared Sub DataTableColumnChanging()
 Dim custTable As 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 ColumnChanging event handler for the table.
 AddHandler custTable.ColumnChanging, New _
 DataColumnChangeEventHandler(AddressOf Column_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 Column_Changing(sender As Object, _
 e As DataColumnChangeEventArgs)
 Console.WriteLine( _
 "Column_Changing Event: name={0}; Column={1}; proposed name={2}", _
 e.Row("name"), e.Column.ColumnName, e.ProposedValue) 
End Sub

Remarks

For more information, see Handling DataTable Events.

See also

• DataTables