datagridview Scroll event not firing when scrolling using keyboard

Question

I am trying to capture the moment when a user ends horizontal scrolling in a datagridview. I need this to reposition buttons in the grid's header.

What I have done so far is adding a scrollListener which I found on this link: How can I receive the "scroll box" type scroll events from a DataGridView?

This works very well, exept that scrolling using the keyboard does not fires the scroll event. When I hoover the mouse in my code over the Scroll event it states "Occurs when the scroll box has been moved by either a mouse or keyboard action". So the event should fire when scrolling with the keyboard, but it does not.

My code is this :

    bool addScrollListener(DataGridView dgv)
    {
        // capture horizonal scrolling and redirect to s_Scroll. Purpose is to redraw buttons after scrolling
        bool Result = false;

        Type t = dgv.GetType();
        PropertyInfo pi = t.GetProperty("HorizontalScrollBar", BindingFlags.Instance | BindingFlags.NonPublic);
        ScrollBar s = null;

        if (pi != null)
            s = pi.GetValue(dgv, null) as ScrollBar;

        if (s != null)
        {
            s.Scroll += new ScrollEventHandler(s_Scroll);

            Result = true;
        }

        return Result;
    }

    void s_Scroll(object sender, ScrollEventArgs e)
    {
        // if grid is done scrolling horizontal, than redraw our buttons
        if (e.Type == ScrollEventType.EndScroll)
        {
            // code works well, but only get here when scrolling with mouse
            PositionButtons();
        }
    }

So my problem is that when the user scrolls using the mouse the s_Scroll event is fired, but when scrolling using the keyboard the s_Scroll event is not fired at all.

My question is how do I fix this so the event gets fired in both cases, and if that is not possible is there another way to capture the end of a horizontal scroll from a datagridview.

Answer 1

In DataGridView , keyboard actions are handled by the DataGridView to update the current cell position.

You must use ScrollBar.ValueChanged event and compare ScrollBar.Value with ScrollBar.Maximum to do what you want.

---

You have another solution to do what you want instead of adding an event listener on ScrollBar.Scroll : handle the DataGridView.Scroll event and verify the datagridview is scrolled down by using DataGridView.FirstDisplayedScrollingRowIndex property and DataGridView.DisplayedRowCount(true) method.

That would be simpler and safer.

Answer 2

private void TransactionsDGV_KeyUp(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.End)
    {
        e.Handled = true;
        DataGridViewCell cell = TransactionsDGV.Rows[TransactionsDGV.Rows.Count-2].Cells[0];
        TransactionsDGV.CurrentCell = cell;
        TransactionsDGV.BeginEdit(true);
        TransactionsDGV.EndEdit();
    }

    if (e.KeyCode == Keys.Home)
    {
        e.Handled = true;
        DataGridViewCell cell = TransactionsDGV.Rows[0].Cells[0];
        TransactionsDGV.CurrentCell = cell;
        TransactionsDGV.BeginEdit(true);
        TransactionsDGV.EndEdit();
    }
}