DataTable.ColumnChanging Event

Occurs when a value is being changed for the specified DataColumn in a DataRow.

Namespace: System.Data
Assembly: System.Data (in

public event DataColumnChangeEventHandler ColumnChanging
/** @event */
public void add_ColumnChanging (DataColumnChangeEventHandler value)

/** @event */
public void remove_ColumnChanging (DataColumnChangeEventHandler value)

JScript supports the use of events, but not the declaration of new ones.

For more information, see Working with DataTable Events.

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++)
            new object[] { id, string.Format(
            "customer{0", id), string.Format("address{0", id) );


    // 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 )
        "Column_Changing Event: name={0; Column={1; proposed name={2", 
        e.Row["name"], e.Column.ColumnName, e.ProposedValue );

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0