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DataSet.MergeFailed Event

Occurs when a target and source DataRow have the same primary key value, and EnforceConstraints is set to true.

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

'Declaration
Public Event MergeFailed As MergeFailedEventHandler
'Usage
Dim instance As DataSet 
Dim handler As MergeFailedEventHandler 

AddHandler instance.MergeFailed, handler

For more information about handling events, see Consuming Events.

The following example demonstrates the use of the MergeFailed event.

Private Shared Sub DemonstrateMergeFailedEvent()
	' Create a DataSet with one table containing two columns. 
	Dim dataSet AS DataSet = New DataSet("dataSet")
	Dim table As DataTable = New DataTable("Items")
	
	' Add table to the DataSet.
	dataSet.Tables.Add(table)

	' Add two columns to the DataTable.
	table.Columns.Add("id", Type.GetType("System.Int32"))
	table.Columns.Add("item", Type.GetType("System.Int32"))

	' Set the primary key to the first column.
	table.PrimaryKey = new DataColumn() { table.Columns("id") }

	' Add MergeFailed event handler for the table. 
	AddHandler dataSet.MergeFailed, _
        New MergeFailedEventHandler(AddressOf Merge_Failed)

	' Create a second DataTable identical to the first,  
	Dim t2 As DataTable = table.Clone()

	' Set the primary key of the new table to the second column. 
	' This will cause the MergeFailed event to be raised when the 
	' table is merged into the DataSet.
	t2.PrimaryKey = New DataColumn() { t2.Columns("item") }
	
	' Merge table into the DataSet.
	Console.WriteLine("Merging...")
	dataSet.Merge(t2, false, MissingSchemaAction.Add)
End Sub 

Private Shared Sub Merge_Failed(sender As object, _
    e As MergeFailedEventArgs)
	Console.WriteLine("Merge_Failed Event: '{0}'", e.Conflict)
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

XNA Framework

Supported in: 3.0, 2.0, 1.0

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