Question

I have a windows form with a listview control. I set the MultiSelect property to true and I added a selected_index changed event.

I get the event fired when I click the same index as the current selected index.
My expectation is that I will not get the event fired. The strange thing is that the event fired 1 second after I click the index.

I appreciate for any reply to explain why this is happening.

Edited:

Sample Code:

private void Form1_Load(object sender, EventArgs e)
{
    listView1.View = View.Details;
    listView1.MultiSelect = true;
    listView1.FullRowSelect = true;

    listView1.Columns.Add("Number");
    listView1.Items.Add("1");
    listView1.Items.Add("2");
    listView1.Items.Add("3");
    listView1.Items.Add("4");
}
private void listView1_SelectedIndexChanged(object sender, EventArgs e)
{
    if (listView1.SelectedItems.Count > 0)
    {
        MessageBox.Show("Selected Index Changed event fired: ");
    }
}

Follow these steps to see the problem:

1. Try to select one item, for instance: select number 3

   expected result: listview1_SelectedIndexChanged is fired

   Result: It is fired.

2. Try to click the number 3 again.

   expected result: listview1_SelectedIndexChanged is NOT fired

   Result: It is fired with one second delay.

Answer 1

From the MSDN documention on ListView.SelectedIndexChangedEvent:

In a multiple selection ListView control, this event occurs whenever an item is removed or added to the list of selected items. To determine which items are selected in the ListView control, use the SelectedItems property to access the ListView.SelectedListViewItemCollection.

As for why the event waited so long to fire: I can only imagine the processor was tied up doing something else. Do you have more details regarding what you’re seeing, exactly (sample code would help)?