> it available. Specifically I'd like to throw an event when a column is
re-sized so that I can capture the column width and save it for later use.
below is an extract from my actual code. as I've said, you can stick to
BeginTrack and EndTrack events. two collections, cNoResize and cNoDrag, can
contain numbers of columns that you do not want the user to resize or drag.
the code will not compile immediately because of attached win32 specific
consts and structs at the end that you have to put in another class. note
also that this is unsafe code.
put a note in the newsgroup if you still have problems. put a note also if
you succeed.
Regards
Wiktor Zychla
namespace Controls
{
public class ListView_0Class : System.Windows.Forms.ListView
{
public delegate void ListViewHeaderNotifEventHandler( object sender,
ListViewHeaderNotifEventArgs e );
[Category("Behavior")]
public event ListViewHeaderNotifEventHandler BeginDrag;
[Category("Behavior")]
public event ListViewHeaderNotifEventHandler BeginTrack;
[Category("Behavior")]
public event ListViewHeaderNotifEventHandler EndDrag;
[Category("Behavior")]
public event ListViewHeaderNotifEventHandler EndTrack;
public ArrayList cNoResize = new ArrayList();
public ArrayList cNoDrag = new ArrayList();
public ListView_0Class() {}
protected override void OnPaintBackground( PaintEventArgs e )
{
}
unsafe protected override void WndProc( ref Message m )
{
HDITEM hditem;
NMHDR nm;
NMHEADER nmheader;
switch ( m.Msg )
{
case (int)Msg.WM_NOTIFY:
nm = (NMHDR) m.GetLParam(typeof(NMHDR));
switch(nm.code)
{
case (int)HeaderControlNotifications.HDN_BEGINTRACKA:
case (int)HeaderControlNotifications.HDN_BEGINTRACKW:
nmheader = (NMHEADER)m.GetLParam(typeof(NMHEADER));
if ( cNoResize.Contains( nmheader.iItem ) )
{
m.Result = (IntPtr)Convert.ToInt32(true);
return;
}
else if ( BeginTrack != null )
BeginTrack( this, new ListViewHeaderNotifEventArgs(
nmheader.iItem ) );
break;
case (int)HeaderControlNotifications.HDN_BEGINDRAG:
nmheader = (NMHEADER)m.GetLParam(typeof(NMHEADER));
if ( cNoDrag.Contains( nmheader.iItem ) )
{
m.Result = (IntPtr)Convert.ToInt32(true);
return;
}
else if ( BeginDrag != null )
BeginDrag( this, new ListViewHeaderNotifEventArgs(
nmheader.iItem ) );
break;
case (int)HeaderControlNotifications.HDN_ENDTRACKA:
case (int)HeaderControlNotifications.HDN_ENDTRACKW:
nmheader = (NMHEADER)m.GetLParam(typeof(NMHEADER));
if ( EndTrack != null )
EndTrack( this, new ListViewHeaderNotifEventArgs(
nmheader.iItem ) );
break;
case (int)HeaderControlNotifications.HDN_ENDDRAG:
nmheader = (NMHEADER)m.GetLParam(typeof(NMHEADER));
hditem = *((HDITEM*)nmheader.pItem.ToPointer());
if ( cNoDrag.Contains( hditem.iOrder ) )
{
m.Result = (IntPtr)Convert.ToInt32(true);
return;
}
else if ( EndDrag != null )
EndDrag( this, new ListViewHeaderNotifEventArgs( nmheader.iItem ) );
break;
default:
break;
}
break;
}
base.WndProc( ref m );
} // end void WndProc
} // end class
public class ListViewHeaderNotifEventArgs : EventArgs
{
public ListViewHeaderNotifEventArgs( int iColumn )
{
this.iColumn = iColumn;
}
public int iColumn;
}
}
[StructLayout(LayoutKind.Sequential)]
public struct NMHDR
{
public IntPtr hwndFrom;
public int idFrom;
public int code;
}
#endregion
// NMHEADER
#region
[StructLayout(LayoutKind.Sequential)]
public struct NMHEADER
{
public NMHDR hdr;
public int iItem;
public int iButton;
public IntPtr pItem;
}
#endregion
// HDITEM
#region
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)]
public struct HDITEM
{
public uint mask;
public int cxy;
public IntPtr pszText;
public IntPtr hbm;
public int cchTextMax;
public int fmt;
public int lParam;
public int iImage;
public int iOrder;
}
#endregion
// Header Control Notifications
#region
public enum HeaderControlNotifications
{
HDN_FIRST = (0-300),
HDN_BEGINTRACKA = (HDN_FIRST-6),
HDN_ENDTRACKA = (HDN_FIRST-7),
HDN_BEGINTRACKW = (HDN_FIRST-26),
HDN_ENDTRACKW = (HDN_FIRST-27),
HDN_ITEMCLICKW = (HDN_FIRST-22),
HDN_BEGINDRAG = (HDN_FIRST-10),
HDN_ENDDRAG = (HDN_FIRST-11),
}
#endregion
