Crashing when right clicking listview

[Porsche944]

I have some code in my MouseUp event for my list view that copies the currently selected index to the clip board. Everything works fine unless you right click on an area on the list view that is no a record. I get this error.


"An unhandled exception of type 'System.ArgumentOutOfRangeException' occurred in system.windows.forms.dll

Additional information: Specified argument was out of the range of valid values"

it happens on this line

Dim lvItem As ListViewItem = lvResults.SelectedItems(0)

Private Sub lvResults_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles lvResults.MouseUp
        'This function is triggered when the mouse button is pressed on the list view control
        'If the mouse button clicked was the right mouse button then copy the
        'description of the currently selected item. 
 
        If e.Button = MouseButtons.Right Then
            Dim lvItem As ListViewItem = lvResults.SelectedItems(0)
            If lvItem.SubItems(1).Text = "" Then
            Else
                Clipboard.SetDataObject(lvItem.SubItems(1).Text, True)
                UpdateStatus(lvItem.SubItems(1).Text & " copied to clipboard")
            End If
        End If
    End Sub

What error handling can I add to this routine so the program won't crash. I can't figure this out and I'm running out of idea's to try. I'm sure it's something simple that I am overlooking.

Thank you,

[apolizoi]

include your code into a Try ...Catch .. Finally block to handle your errors..

[Negative0]

Make sure that you have an item selected in your listview:

If  lvResults.SelectedItems.Count > 0 Then
       If e.Button = MouseButtons.Right Then
            Dim lvItem As ListViewItem = lvResults.SelectedItems(0)
            If lvItem.SubItems(1).Text = "" Then
            Else
                Clipboard.SetDataObject(lvItem.SubItems(1).Text, True)
                UpdateStatus(lvItem.SubItems(1).Text & " copied to clipboard")
            End If
        End If
  end if

But also listen to apolizoi about adding Try Catch blocks to your code.

[jmcilhinney]

You should definitely use Try...Catch blocks in areas of your code where FACTORS BEYOND YOUR CONTROL may cause an exception to be thrown. These would include IO and data access operations, amongst others. This is not one of those times, though. As Negative0's code shows, there is no need for an exception to be thrown because you can check yourself beforehand whether your code will be valid or not. You should not just use exception handling willy-nilly as a substitute for writing efficient, robust code. Just the use of exception handlers has an impact, although it's very slight in most cases. Actually throwing an exception is an expensive operation though, and should be avoided if at all possible. Never use exception handling to control program flow if it is at all possible to avoid.

[Porsche944]

That's what I needed the selecteditems count. Why didn't I think of that before. :O

Thanks for the help guys and your right this error dosen't randomly pop up and it should be handled correctly. I only use the Try Catch's on area's of code I haven't experianced an error on yet but, seem likely to produce one.