// Setting the virtual list size this way eliminates flickering (when invalidate = false)
// and prevents the control from scrolling to the right.
// This idea came from http://www.dotnetmonster.com/Uwe/Forum.aspx/winform-controls/5181/Ugly-flicker-when-updating-a-ListView-in-VirtualMode
public void SetVirtualListSize(int count, bool invalidate)
{
if (listViewVirtualListSizeField == null)
{
VirtualListSize = count;
}
else
{
try
{
ListViewSetItemCountFlags flags = ListViewSetItemCountFlags.LVSICF_NOSCROLL;
if (!invalidate)
{
flags |= ListViewSetItemCountFlags.LVSICF_NOINVALIDATEALL;
}
SendMessage(Handle, ListViewMessages.LVM_SETITEMCOUNT, count, flags);
// The public ListView.VirtualListSize property drives a private member
// named virtualListSize that is used in the implementation of
// ListViewItemCollection (returned by ListView.Items) to validate
// indices. If this is not updated, spurious ArgumentOutOfRangeExceptions
// may be raised by functions and properties using the indexing
// operator on ListView.Items, for instance FocusedItem.
listViewVirtualListSizeField.SetValue(this, count);
}
catch
{
VirtualListSize = count;
}
}
}
private static extern IntPtr SendMessage(IntPtr hWnd, ListViewMessages msg, int wParam, ListViewSetItemCountFlags lParam);