这是我的特殊控件，其中包含一个不透明度属性，它100％有效：
using System;using System.Collections;using System.ComponentModel;using System.ComponentModel.Design;using System.Drawing;using System.Windows.Forms;using System.Windows.Forms.Design;public class TranspCtrl : Control{ public bool drag = false; public bool enab = false; private int m_opacity = 100; private int alpha; public TranspCtrl() { SetStyle(ControlStyles.SupportsTransparentBackColor, true); SetStyle(ControlStyles.Opaque, true); this.BackColor = Color.Transparent; } public int Opacity { get { if (m_opacity > 100) { m_opacity = 100; } else if (m_opacity < 1) { m_opacity = 1; } return this.m_opacity; } set { this.m_opacity = value; if (this.Parent != null) { Parent.Invalidate(this.Bounds, true); } } } protected override CreateParams CreateParams { get { CreateParams cp = base.CreateParams; cp.ExStyle = cp.ExStyle | 0x20; return cp; } } protected override void onPaint(PaintEventArgs e) { Graphics g = e.Graphics; Rectangle bounds = new Rectangle(0, 0, this.Width - 1, this.Height - 1); Color frmColor = this.Parent.BackColor; Brush bckColor = default(Brush); alpha = (m_opacity * 255) / 100; if (drag) { Color dragBckColor = default(Color); if (BackColor != Color.Transparent) { int Rb = BackColor.R * alpha / 255 + frmColor.R * (255 - alpha) / 255; int Gb = BackColor.G * alpha / 255 + frmColor.G * (255 - alpha) / 255; int Bb = BackColor.B * alpha / 255 + frmColor.B * (255 - alpha) / 255; dragBckColor = Color.FromArgb(Rb, Gb, Bb); } else { dragBckColor = frmColor; } alpha = 255; bckColor = new SolidBrush(Color.FromArgb(alpha, dragBckColor)); } else { bckColor = new SolidBrush(Color.FromArgb(alpha, this.BackColor)); } if (this.BackColor != Color.Transparent | drag) { g.FillRectangle(bckColor, bounds); } bckColor.Dispose(); g.Dispose(); base.onPaint(e); } protected override void onBackColorChanged(EventArgs e) { if (this.Parent != null) { Parent.Invalidate(this.Bounds, true); } base.onBackColorChanged(e); } protected override void onParentBackColorChanged(EventArgs e) { this.Invalidate(); base.onParentBackColorChanged(e); }}
