CODEWITHSUNDEEP
vb.netdrag-and-drop
Alin I
Alin I

Reputation: 590

Drag&Drop between 2 datagriviews back and forth duplicating action

I'm trying to implement dragging and dropping between two datagridviews in the same form. I have DataGridView1 and DataGridView2 with datasource bound to SQL Server View. and the following code:

 Private Sub DataGridView1_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles DataGridView1.MouseDown
        Dim Index As Integer
        Index = DataGridView1.HitTest(e.X, e.Y).RowIndex
        If Index > -1 Then
            'Pass the Index as "Data" argument of the DoDragDrop Function
            Me.DataGridView1.Rows(Index).Selected = True
            DataGridView1.DoDragDrop(Index, DragDropEffects.Move)
        End If
 End Sub

Private Sub DataGridView2_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles DataGridView2.MouseDown
    Dim Index As Integer
    Index = DataGridView2.HitTest(e.X, e.Y).RowIndex
    If Index > -1 Then
        'Pass the Index as "Data" argument of the DoDragDrop Function
        Me.DataGridView2.Rows(Index).Selected = True
        DataGridView1.DoDragDrop(Index, DragDropEffects.Move)
    End If
End Sub

Private Sub DataGridView1_DragDrop(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles DataGridView1.DragDrop
    Try
        Dim myID As Integer = Convert.ToInt32(e.Data.GetData(Type.GetType("System.Int32")))

        (...
         code to execute query to add selected value to a table
         ...) 

    Catch ex As Exception
        MsgBox(ex.Message)
    End Try
End Sub

Private Sub DataGridView2_DragDrop(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles DataGridView2.DragDrop
    Try
        Dim myID As Integer = Convert.ToInt32(e.Data.GetData(Type.GetType("System.Int32")))

        (...
         code to execute query to delete selected value from a table
         ...)    
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try
End Sub

Everything works just almost as planned:
If I move a record from first datagrid and drag it to the second and drop it, all code works ok, the record is moved through SQL to second datagridview, but then, if I click on the second datagridview, the drag event fires again and it's like dragging from second datagrid to first datagrid. How can I prevent this behaviour.

Upvotes: 1

Views: 4348

Answers (1)

Dragos Bobolea
Dragos Bobolea

Reputation: 782

In your _MouseDown methods, on the second one you have the DoDragDrop() execute on DataGridView*1*, you forgot to change it: 

 Me.DataGridView***2***.Rows(Index).Selected = True
 DataGridView***1***.DoDragDrop(Index, DragDropEffects.Move)DataGridView1.DoDragDrop(Index, DragDropEffects.Move)

Edit: note that it is a very bad practice to duplicate code like this. What I would do is make one method which gets the DataGridView as parameter, and in the 2 identical methods call this one with that respective object. Then, you only have to design, debug and maintain only one piece of code.

Upvotes: 1

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