VB.NET在空字段中单击鼠标时取消选中列表框中的项目

Question

I have a listbox ( mainlistbox ) that lists files in a specified directory. When I click them in the listbox I get a preview of the file in a richtextbox. This works perfectly, but I'm trying to figure out how to unselect an item in the mainlistbox when I mouse click in a empty field in the listbox.

Mainlistbox selectedindexchanged does thing like if file exists, file.readalltext to the textbox.

I'm now working on the event for mouse click on mainlistbox.

    Private Sub MainListBox_MouseClick(sender As Object, e As MouseEventArgs) Handles MainListBox.MouseClick

    If (MainListBox.SelectedIndex = -1) Then 'This is where I've tried "everything"
        MainListBox.ClearSelected()
end if

It seems to work before I got a item selected (tested using msgbox), but after I've selected one, I just can't unselect it. I've tried a bunch of variations, but I can't get it to work. Its probably something super simple that I've just not figure out yet. Thanks!

Answer 1

you can check on the mouse up if an item has been clicked, and if not clear your data:

Private Sub MainListBox_MouseUp(sender As Object, e As MouseEventArgs) Handles MainListBox.MouseUp
If MainListBox.IndexFromPoint(e.Location) < 0 Then
  ' clear the data
End If
End Sub