protected virtual void OnPaint(GroupPaintEventArgs e)
{
if (Paint != null)
{
Paint.Invoke(this, e);
}
}
private void PaintGroup(int i)
{
var groupId = GetGroupId(i);
var rect = new RECT {
Top = LVGGR_HEADER
};
var rectSize = Marshal.SizeOf(typeof(RECT));
var lParam = Marshal.AllocHGlobal(rectSize);
try
{
Marshal.StructureToPtr(rect, lParam, false);
var retVal = SendMessage(_listView.Handle, LVM_GETGROUPRECT, new IntPtr(groupId), lParam);
if (retVal == IntPtr.Zero)
{
return;
}
var retRc = (RECT)Marshal.PtrToStructure(lParam, typeof(RECT));
using (var g = Graphics.FromHwnd(_listView.Handle))
{
var groupRect =
new Rectangle(retRc.Left, retRc.Top, retRc.Right - retRc.Left, retRc.Bottom - retRc.Top);
var args = new GroupPaintEventArgs(i - 1, g, groupRect);
OnPaint(args);
}
}
finally
{
Marshal.FreeHGlobal(lParam);
}
}
private void HandleGroupsPaint(object sender, GroupPaintEventArgs e)
{
if (!_enabled || !GroupColorsAreDefined())
{
return;
}
// We have to redraw whole background. BufferedGraphicsContext is created to prevent flickering.
using (var context = new BufferedGraphicsContext())
using (var g = context.Allocate(e.Graphics, e.ClipRectangle))
using (var highlightBrush = new SolidBrush(_theme.ListView.GroupHighlightColor))
using (var backBrush = new SolidBrush(_theme.ListView.GroupBackColor))
using (var foreBrush = new SolidBrush(_theme.ListView.GroupForeColor))
using (var forePen = new Pen(_theme.ListView.GroupForeColor))
using (var columnPen = new Pen(_theme.ListView.ColumnBorderColor))
{
var isMouseOver = e.ClipRectangle.Contains(_listView.PointToClient(MousePosition));
g.Graphics.FillRectangle(isMouseOver ? highlightBrush : backBrush, e.ClipRectangle);
var font = new Font(_listView.Font, FontStyle.Bold);
var textSize = e.Graphics.MeasureString(" " + _listView.Groups[e.GroupId].Header + " ", font);
var textRect = new Rectangle(
e.ClipRectangle.X + 8, e.ClipRectangle.Y, (int)textSize.Width, e.ClipRectangle.Height - 1);
var sf = new StringFormat {
Alignment = StringAlignment.Center, LineAlignment = StringAlignment.Center
};
g.Graphics.DrawString(_listView.Groups[e.GroupId].Header, _listView.Font, foreBrush, textRect, sf);
var columnOffset = -2; // Initial padding
foreach (ColumnHeader column in _listView.Columns)
{
columnOffset += column.Width;
g.Graphics.DrawLine(columnPen, e.ClipRectangle.X + columnOffset, e.ClipRectangle.Y,
e.ClipRectangle.X + columnOffset, e.ClipRectangle.Bottom);
}
var lineY = e.ClipRectangle.Y + e.ClipRectangle.Height / 2;
g.Graphics.DrawLine(forePen, textRect.Right, lineY, e.ClipRectangle.Right, lineY);
g.Render(e.Graphics);
sf.Dispose();
}
}
