c# 透明panel 示例代码

using System;using System.Collections.Generic;using System.ComponentModel;using System.Drawing;using System.Drawing.Drawing2D;using System.Text;using System.Windows.Forms;namespace Nova.Controls.Panel{ public class TransparentPanel : Control { private Color _borderColor; private int _borderWidth = 1; private DashStyle _borderStyle = DashStyle.Solid; private int _opacity = 125; public TransparentPanel() { } #region Property //[Category("Custom"), Description("Border Color")] //public Color BorderColor //{ // set { _borderColor = value; this.Invalidate(); } // get { return _borderColor; } //} //[Category("Custom"), Description("Border Width"), DefaultValue(1)] //public int BorderWidth //{ // set // { // if (value < 0) value = 0; // _borderWidth = value; // this.Invalidate(); // } // get { return _borderWidth; } //} //[Category("Custom"), Description("Border Style"), DefaultValue(DashStyle.Solid)] //public DashStyle BorderStyle //{ // set { this._borderStyle = value; this.Invalidate(); } // get { return this._borderStyle; } //} [Bindable(true), Category("Custom"), DefaultValue(125), Description("背景的透明度. 有效值0-255")] public int Opacity { get { return _opacity; } set { if (value > 255) value = 255; else if (value < 0) value = 0; _opacity = value; this.Invalidate(); } } #endregion protected override void OnPaintBackground(PaintEventArgs e) { //do not allow the background to be painted } protected override CreateParams CreateParams { get { CreateParams cp = base.CreateParams; cp.ExStyle |= 0x00000020; //WS_EX_TRANSPARENT return cp; } } protected override void OnPaint(PaintEventArgs e) { Graphics g = e.Graphics; g.FillRectangle(new SolidBrush(Color.FromArgb(this._opacity, this.BackColor)), this.ClientRectangle); base.OnPaint(e); } }}