ComboBox SelectChangeCommited fires off with first keyboard input

Question

I have a ComboBox. My issue is when I click on element 1, then start typing the name of a element 2, the first letter of my element 2 gets added. This only happens on the key down after a click event.

Process:

Click on ComboBox
Type in a name
Click on the elements name - element gets added to my grid
Type in another name - ISSUE - first element that matches the first letter I input gets added to the grid

Clicking and the enter key on a single selected element works fine.

My AutoCompleteMode is set to Append and AutoCompleteSource is ListItems

The solution I thought to control a click is in my SelectionChangeComitted function. If I can control the flag isCLick to only be set true when we know that a element from the combo box is clicked by the mouse. MouseClick will return true if the user clicks on the overall ComboBox therefore will always be true if we're dealing with this particular ComboBox. Since the parameter is EventArgs I cannot directly cast it to MouseEventArgs, would be great if I could.

To sum up what my problem is: I need to replace isClick boolean in my SelectionChangeCommitted to validate if the SelectionChangeCommitted was triggered by a click or not.

Is that possible in this case? Would there be any alternatives to bypass this issue?

I have event handler code below, the sequence of the call is: MouseClick -> PreviewKeyDown -> SelectionChangeCommitted -> SelectedValueChanged

http://pastebin.com/9zWGHbWE

AddHandler CType(ctl, ComboBox).PreviewKeyDown, Sub(sender As Object, e As PreviewKeyDownEventArgs)
                                                                If e.KeyCode = Keys.Down OrElse e.KeyCode = Keys.Up OrElse e.KeyCode = Keys.Right OrElse e.KeyCode = Keys.Left Then
                                                                    e.IsInputKey = False
                                                                    AddToGrid = False
                                                                    isArrowKey = True
                                                                    isClick = False
                                                                ElseIf e.KeyCode = Keys.Enter OrElse e.KeyCode = Keys.Tab Then
                                                                    AddToGrid = True
                                                                    isArrowKey = False
                                                                    isClick = False
                                                                    'Check if row already exists before insert a new one.
                                                                    If Not RowExists(DirectCast(ctl, Control).Tag, DirectCast(ctl, ComboBox).Text.ToUpper()) Then AppendGrid(sender)

                                                                Else
                                                                    AddToGrid = False
                                                                    isArrowKey = False
                                                                    isClick = True
                                                                End If
                                                            End Sub

            AddHandler CType(ctl, ComboBox).SelectedValueChanged, Sub(sender As Object, e As EventArgs)
                                                                      'MessageBox.Show("SelectionValueChanged")
                                                                      If CType(sender, ComboBox).SelectedValue Is Nothing Then Return
                                                                      If Not AddToGrid Then Return

                                                                      'Check if row already exists before insert a new one.
                                                                      If Not RowExists(DirectCast(ctl, Control).Tag, DirectCast(ctl, ComboBox).SelectedValue.ToString().ToUpper()) Then
                                                                          AppendGrid(sender)
                                                                      End If
                                                                  End Sub

            AddHandler CType(ctl, ComboBox).SelectionChangeCommitted, Sub(sender As Object, e As EventArgs)
                                                                          'MessageBox.Show("SelectionChangedCommitted")


                                                                          If CType(sender, ComboBox).SelectedValue Is Nothing Then Return
                                                                          If isArrowKey Then Return 'if an arrow was used, then don't add it to the grid

                                                                          If isClick Then
                                                                              AddToGrid = True
                                                                          End If

                                                                          'Check if row already exists before insert a new one.
                                                                          If Not RowExists(DirectCast(ctl, Control).Tag, DirectCast(ctl, ComboBox).SelectedValue.ToString().ToUpper()) AndAlso AddToGrid Then
                                                                              AppendGrid(sender)

                                                                          End If


                                                                      End Sub

            AddHandler CType(ctl, ComboBox).MouseClick, Sub(sender As Object, e As MouseEventArgs)
                                                            'MessageBox.Show("MouseClick")
                                                            isClick = True
                                                            AddToGrid = True
                                                        End Sub

WozzeC WozzeC · Accepted Answer · 2014-05-23T07:19:44

It seems like everything here works fine for you except when a click is executed. I would recommend you to reset the click after you use it. Try the code below in your SelectionChangeCommitted.

If isClick Then
    AddToGrid = True
    isClick = false
End If

ComboBox SelectChangeCommited fires off with first keyboard input

1 Answers