Detect if mouse click hits a item not in listbox [C#]

If the user click on a item in the listbox, the listboxItems_Se开发者_StackOverflow中文版lectedIndexChanged is called. But, even if the user miss an item and randomly clicks inside the listbox (not on items) the listboxItems_SelectedIndexChanged is still called.

How can I change this? I only want action on item click.

Note: removing the ability to navigate the application with keyboard is not a option.

I guess that in some cases you don't have enough list items in your control, therefore you have some space that you can click on and then SelectedIndexChanged is fired.

I guess you cannot dynamically resize the control to always fit the number of list items or else you wouldn't be asking this question.

Now, what should happen when the user click (selects) the same list item? Should some logic happen even though the selected index is the same (so when it was clicked the first time the same logic happend)?

If you require that selecting the same index more than once should be ignored then you could use the following hack:

Keep a variable at the form scope (the form containing the listbox control) and each time the selection index changes set that variable. Then use it later to check if the same selection has been made to ignore handling the event. Here is an example:

 private int _currSelIdx = -1; // Default value for the selected index when no selection
 private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
 {
      if (listBox1.SelectedIndex == _currSelIdx)
         return;

      Console.WriteLine(listBox1.SelectedIndex);
      _currSelIdx = listBox1.SelectedIndex;
 }

It ain't pretty, but hey...whatever works!

Maybe SelectedIndexChanged is not the right place to put your logic, since it is triggered even when you change the selection with the keyboard. I would use MouseClick instead, checking if the click occurred over the selected item, i.e. something like this:

    private void listBox1_MouseClick(object sender, MouseEventArgs e)
    {
        if (listBox1.SelectedIndex < 0 || !listBox1.GetItemRectangle(listBox1.SelectedIndex).Contains(e.Location))
            MessageBox.Show("no click");
        else
            MessageBox.Show("click on item " + listBox1.SelectedIndex.ToString());
    }

This link may help, instead of double click, implement the same for single click

i want to detect an item double click in a winforms listbox control. [how to handle click on blank area?]