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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)

'Declaration
Public Event ColumnChanging As DataColumnChangeEventHandler
'Usage
Dim instance As DataTable 
Dim handler As DataColumnChangeEventHandler 

AddHandler instance.ColumnChanging, handler

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) })
	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

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

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

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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