Saya membuat kotak kombo khusus di .net framework 1.1, saya dapat menggambar item tarik-turun secara khusus, tetapi saya tidak dapat mengatur atau menggambar teks kotak kombo di Kiri Tengah, teks kotak kombo selalu ditampilkan di kiri atas, tetapi saya memerlukan teks harus dirender di kiri tengah .
[ToolboxBitmap(typeof(ComboBox))]
public class MenComboBox :ComboBox
{
private Image _image = Image.FromFile("Expand.png");
public MenComboBox()
{
this.DrawMode = DrawMode.OwnerDrawFixed;
this.BackColor = Color.White;
this.ItemHeight = 18;
this.Font = new Font("Arial",12f,FontStyle.Regular);
}
protected override void OnDrawItem(DrawItemEventArgs e)
{
if (!DesignMode)
{
if (e.Index > -1)
{
int textHeight = (int)e.Graphics.MeasureString(this.Items[e.Index].ToString(), e.Font).Height;
Point textPos = new Point(e.Bounds.X + 4, e.Bounds.Y + ((this.ItemHeight - textHeight) / 2));
if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
{
e.Graphics.FillRectangle(Brushes.Blue, e.Bounds);
e.Graphics.DrawString(this.Items[e.Index].ToString(),e.Font,Brushes.White,textPos);
}
else
{
e.Graphics.FillRectangle(Brushes.White, e.Bounds);
e.Graphics.DrawString(this.Items[e.Index].ToString(),e.Font,Brushes.Black,textPos);
}
}
}
}
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
if (m.Msg == 0x000F)
{
using (Graphics g = this.CreateGraphics())
{
g.FillRectangle(new SolidBrush(BackColor), this.ClientRectangle);
g.DrawRectangle(Pens.Blue, new Rectangle(this.ClientRectangle.X, this.ClientRectangle.Y, this.ClientRectangle.Width - 1, this.ClientRectangle.Height - 1));
Rectangle rect = new Rectangle(this.Width - 15, 3, 12, this.Height - 6);
g.FillRectangle(new SolidBrush(BackColor), rect);
g.DrawImage(this._image, this.Width - 16, (this.Height - 8) / 2);
g.Dispose();
}
}
}
}