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DataTable.ColumnChanging Event

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

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

Public Event ColumnChanging As DataColumnChangeEventHandler

Private Shared Sub DataTableColumnChanging()
	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 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) })

	' 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"))

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

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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