// Main paiting method
protected override void OnDrawItem(DrawItemEventArgs e)
{
int maxItem = this.Items.Count - 1;
if (e.Index < 0 || e.Index > maxItem)
{
// Erase all background if control has no items
e.Graphics.FillRectangle(BackBrush, this.ClientRectangle);
return;
}
int size = e.Font.Height; // button size depends on font height, not on item height
// Calculate bounds for background, if last item paint up to bottom of control
Rectangle backRect = e.Bounds;
if (e.Index == maxItem)
{
backRect.Height = this.ClientRectangle.Top + this.ClientRectangle.Height - e.Bounds.Top;
}
e.Graphics.FillRectangle(BackBrush, backRect);
// Determines text color/brush
Brush textBrush;
bool isChecked = (e.State & DrawItemState.Selected) == DrawItemState.Selected;
RadioButtonState state = isChecked ? RadioButtonState.CheckedNormal : RadioButtonState.UncheckedNormal;
if ((e.State & DrawItemState.Disabled) == DrawItemState.Disabled)
{
textBrush = SystemBrushes.GrayText;
state = isChecked ? RadioButtonState.CheckedDisabled : RadioButtonState.UncheckedDisabled;
}
else if ((e.State & DrawItemState.Grayed) == DrawItemState.Grayed)
{
textBrush = SystemBrushes.GrayText;
state = isChecked ? RadioButtonState.CheckedDisabled : RadioButtonState.UncheckedDisabled;
}
else
{
textBrush = SystemBrushes.FromSystemColor(this.ForeColor);
}
// Determines bounds for text and radio button
Size glyphSize = RadioButtonRenderer.GetGlyphSize(e.Graphics, state);
Point glyphLocation = e.Bounds.Location;
glyphLocation.Y += (e.Bounds.Height - glyphSize.Height) / 2;
Rectangle bounds = new Rectangle(e.Bounds.X + glyphSize.Width, e.Bounds.Y, e.Bounds.Width - glyphSize.Width, e.Bounds.Height);
// Draws the radio button
RadioButtonRenderer.DrawRadioButton(e.Graphics, glyphLocation, state);
// Draws the text
if (!string.IsNullOrEmpty(DisplayMember)) // Bound Datatable? Then show the column written in Displaymember
{
e.Graphics.DrawString(((System.Data.DataRowView) this.Items[e.Index])[this.DisplayMember].ToString(),
e.Font, textBrush, bounds, this.Align);
}
else
{
e.Graphics.DrawString(this.Items[e.Index].ToString(), e.Font, textBrush, bounds, this.Align);
}
// If the ListBox has focus, draw a focus rectangle around the selected item.
e.DrawFocusRectangle();
}
