OleDbDataAdapter.RowUpdating Event


Occurs during Update before a command is executed against the data source. The attempt to update is made. Therefore, the event occurs.

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

Public Event RowUpdating As OleDbRowUpdatingEventHandler

When you use Update, there are two events that occur per data row updated. The order of execution is as follows:

  1. The values in the DataRow are moved to the parameter values.

  2. The OnRowUpdating event is raised.

  3. The command executes.

  4. If the command is set to FirstReturnedRecord, the first returned result is placed in the DataRow.

  5. If there are output parameters, they are placed in the DataRow.

  6. The OnRowUpdated event is raised.

  7. AcceptChanges is called.

The following example shows the RowUpdating and RowUpdated events being used.

Public Sub CreateDataAdapter(ByVal connectionString As String)
    Using connection As New OleDbConnection(connectionString)
        Dim adapter As OleDbDataAdapter = New OleDbDataAdapter( _
            "SELECT * FROM Customers WHERE CustomerID = 'ALFKI'", connection)

        adapter.InsertCommand = New OleDbCommand( _
            "INSERT INTO Customers (CustomerID, CompanyName) VALUES(?, ?)", _

        adapter.InsertCommand.Parameters.Add( _
            "@CustomerID", OleDbType.VarChar, 5, "CustomerID")
        adapter.InsertCommand.Parameters.Add( _
            "@CompanyName", OleDbType.VarChar, 30, "CompanyName")


        Dim custDS As DataSet = New DataSet()
        adapter.Fill(custDS, "Customers")

        Dim custRow As DataRow = custDS.Tables("Customers").NewRow()
        custRow("CustomerID") = "NEWCO"
        custRow("CompanyName") = "New Company"

        ' add handlers
        AddHandler adapter.RowUpdating, _
            New OleDbRowUpdatingEventHandler(AddressOf OnRowUpdating)
        AddHandler adapter.RowUpdated, _
            New OleDbRowUpdatedEventHandler(AddressOf OnRowUpdated)

        adapter.Update(custDS, "Customers")

        ' remove handlers
        RemoveHandler adapter.RowUpdating, _
            New OleDbRowUpdatingEventHandler(AddressOf OnRowUpdating)
        RemoveHandler adapter.RowUpdated, _
            New OleDbRowUpdatedEventHandler(AddressOf OnRowUpdated)

        Dim row As DataRow
        For Each row In custDS.Tables("Customers").Rows
            If row.HasErrors Then Console.WriteLine(row.RowError)
    End Using
End Sub

Sub OnRowUpdating(ByVal sender As Object, _
    ByVal args As OleDbRowUpdatingEventArgs)

    If args.StatementType = StatementType.Insert Then
        Dim writer As System.IO.TextWriter = _
        writer.WriteLine("{0}: Customer {1} Inserted.", _
            DateTime.Now, args.Row("CustomerID"))
    End If
End Sub

Sub OnRowUpdated(ByVal sender As Object, _
    ByVal args As OleDbRowUpdatedEventArgs)

    If args.Status = UpdateStatus.ErrorsOccurred Then
        args.Row.RowError = args.Errors.Message
        args.Status = UpdateStatus.SkipCurrentRow
    End If
End Sub

.NET Framework
Available since 1.1
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