Display Context Menu on DataGridView only when specifc keys are pressed...

  • Thread starter Thread starter hzgt9b
  • Start date Start date
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hzgt9b

Using VS2005, VB.NET,
I am developing a windows app that has a DataGridView. I want to
enable the display of a context menu on this DataGridView only when a
specific set of keys is also pressed (like CTRL+ALT+SHIFT). TO this
point I have code that only displays the context menu while keys CTRL
+ALT+SHIFT are pressed - but after the keys are released the context
menu still gets displayed. Can someone tell me where the following
code is wrong.

'Assume:
' 1. There is a control named MyDataGridView on the form
' 2. That MyDataGridView's DataSource is a DataView filled with
several rows of data
'
Public Class MyForm
Private intMyDataGridView_CurrentRow As Int16
Private MyContextMenu As ContextMenu = Nothing
Private bCtrl_Alt_Shift As Boolean = False

Private Sub myForm_Load(ByVal sender As Object, ByVal e As
System.EventArgs) Handles Me.Load
Me.MyContextMenu = New ContextMenu()
Me.MyContextMenu.MenuItems.Add("MyContextMenu's Action", New
EventHandler(AddressOf Me.MyContextMenu_Action))
End Sub

Private Sub MyContextMenu_Action(ByVal sender As Object, ByVal e
As System.EventArgs)
MsgBox("My Data Grid View Action called!")
End Sub

Private Sub MyForm_KeyDown(ByVal sender As Object, ByVal e As
System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
If e.Control AndAlso e.Alt AndAlso e.Shift Then
Me.bCtrl_Alt_Shift = True
Else
Me.bCtrl_Alt_Shift = False
End If
End Sub

Private Sub MyForm_KeyUp(ByVal sender As Object, ByVal e As
System.Windows.Forms.KeyEventArgs) Handles Me.KeyUp
If e.Control AndAlso e.Alt AndAlso e.Shift Then
Me.bCtrl_Alt_Shift = True
Else
Me.bCtrl_Alt_Shift = False
End If
End Sub

Private Sub MyDataGridView_MouseDown(ByVal sender As Object, ByVal
e As System.Windows.Forms.MouseEventArgs) Handles
MyDataGridView.MouseDown
'Next LINE: Try to remove the context menu - this doesn't seem to
remove the context menu once it has already been... I only want the
context menu to display when bCtrl_Alt_Shift is True - HELP
Me.ContextMenu = Nothing
If Me.bCtrl_Alt_Shift Then
Dim hti As DataGridView.HitTestInfo =
Me.MyDataGridView.HitTest(e.X, e.Y)
If hti.ColumnIndex = -1 Then 'no content menu on header
row
Else
Try
Me.ContextMenu = Me.MyContextMenu
Me.intMyDataGridView_CurrentRow = hti.RowIndex
Catch ex As Exception
Me.LogError("MyDataGridView_MouseDown",
"MyDataGridView CONTEXT MENU", ex.ToString)
End Try
End If
End If
End Sub
End Class
 
I got this to work by using
Control.ModifierKeys = Keys.Control + Keys.Shift + Keys.Alt

Versus updating a global variable (bCtrl_Alt_Shift) as keys were
pressed.

The new mouse down procedure looks like this:

Private Sub MyDataGridView_MouseDown(ByVal sender As Object, ByVal e
As System.Windows.Forms.MouseEventArgs) Handles
MyDataGridView.MouseDown
Try
Me.MyContextMenu.Items(0).Visible = False 'Make the menu
item(s) invisible
Dim hti As DataGridView.HitTestInfo =
Me.MyDataGridView.HitTest(e.X, e.Y)
If hti.ColumnIndex = -1 OrElse hti.RowIndex = -1 Then 'no
content menu on header row
Else
If e.Button = Windows.Forms.MouseButtons.Right AndAlso
Control.ModifierKeys = Keys.Control + Keys.Shift + Keys.Alt Then
Me.MyContextMenu.Items(0).Visible = True
End If
End If
Catch ex As Exception 'TODO handle error
End Try
 
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