CODEWITHSUNDEEP
c#.netwinformsdatagridview
shahab
shahab

Reputation: 71

"SelectedIndexChanged" event in ComboBoxColumn on Datagridview

I want to handle this event "SelectedIndexChanged" on a DataGridViewComboBoxColumn, and I set it on "EditingControlShowing" event of the gridview.

The problem : "SelectedIndexChanged" event is not fired on first attempt of selecting an Item from the comboBox, but after selecting that item for the second time the event is fired and everything works fine !

Here is the code:

private void dgvRequest_EditingControlShowing(object sender,
     DataGridViewEditingControlShowingEventArgs e)
{
    ComboBox combo = e.Control as ComboBox;

    if (combo != null)
    {
        if (dgvRequest.CurrentCell.ColumnIndex == col_ConfirmCmb.Index)
        {
            combo.SelectedIndexChanged -= combo_ConfirmSelectionChange;
            combo.SelectedIndexChanged += combo_ConfirmSelectionChange;

            return;
        }
    }
}


void combo_ConfirmSelectionChange(object sender, EventArgs e)
{
    if (dgvRequest.CurrentCell.ColumnIndex != col_ConfirmCmb.Index) return;

    ComboBox combo = sender as ComboBox;
    if (combo == null) return;

    MessageBox.Show(combo.SelectedText);// returns Null for the first time
}

Upvotes: 2

Views: 14167

Answers (1)

Sam Trost
Sam Trost

Reputation: 2173

Things get complicated since they optimized the DataGridView by only having one editing control for all the rows. Here's how I handled a similar situation:

First hook up a delegate to the EditControlShowing event:

myGrid.EditingControlShowing += new DataGridViewEditingControlShowingEventHandler(
                                    Grid_EditingControlShowing);
...

Then in the handler, hook up to the EditControl's SelectedValueChanged event:

void Grid_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
    ComboBox combo = e.Control as ComboBox;
    if (combo != null)
    {
        // the event to handle combo changes
        EventHandler comboDelegate = new EventHandler(
            (cbSender, args) =>
            {
                DoSomeStuff();
            });

        // register the event with the editing control
        combo.SelectedValueChanged += comboDelegate;

        // since we don't want to add this event multiple times, when the 
        // editing control is hidden, we must remove the handler we added.
        EventHandler visibilityDelegate = null;
        visibilityDelegate = new EventHandler(
            (visSender, args) =>
            {
                // remove the handlers when the editing control is
                // no longer visible.
                if ((visSender as Control).Visible == false)
                {
                    combo.SelectedValueChanged -= comboDelegate;
                    visSender.VisibleChanged -= visibilityDelegate;
                }
            });

        (sender as DataGridView).EditingControl.VisibleChanged += 
           visibilityDelegate;

    }
}

Upvotes: 6

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