c# winform 支持透明度的自定义panel，当拖动改变大小的时候怎样取消闪烁？控件代码如下:
//代码有点长，但是功能很简单using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
namespace DragPanel
{
public class OpacityPanel : Panel
{
#region 定义字段
/// <summary>
/// 透明度
/// </summary>
private int _alpha = 100;
/// <summary>
/// 背景颜色
/// </summary>
private Color _bkcolor = DefaultBackColor;
/// <summary>
/// 边框颜色
/// </summary>
private Color _bdcolor = DefaultBackColor;
/// <summary>
///
/// </summary>
private const int Band = 5;
/// <summary>
/// 最小宽度
/// </summary>
private const int MinWidth = 10;
/// <summary>
/// 鼠标状态
/// </summary>
private EnumMousePointPosition m_MousePointPosition;
/// <summary>
/// 鼠标按下点
/// </summary>
private Point DownPoint;
/// <summary>
/// 鼠标移动点
/// </summary>
private Point CurrPoint;
#endregion
#region 定义属性
/// <summary>
/// 透明度
/// </summary>
public int Alpha
{
get
{
return _alpha;
}
set
{
_alpha = value;
this.Invalidate();
this.Update();
}
}
/// <summary>
/// 背景颜色
/// </summary>
public Color bkColor
{
get
{
return _bkcolor;
}
set
{
_bkcolor = value;
this.Invalidate();
this.Update();
}
}
/// <summary>
/// 边框颜色
/// </summary>
public Color bdColor
{
get
{
return _bdcolor;
}
set
{
_bdcolor = value;
this.Invalidate();
this.Update();
}
}
#endregion
#region 构造函数
public OpacityPanel()
{
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
SetStyle(ControlStyles.Opaque, true);
SetStyle(ControlStyles.UserPaint, true);
SetStyle(ControlStyles.AllPaintingInWmPaint, true);
this.MouseDown += new System.Windows.Forms.MouseEventHandler(MyMouseDown);
this.MouseLeave += new System.EventHandler(MyMouseLeave);
this.MouseMove += new System.Windows.Forms.MouseEventHandler(MyMouseMove);
}
/// <summary>
/// 背景透明panel
/// </summary>
/// <param name="alpha">透明度</param>
/// <param name="back">背景颜色</param>
/// <param name="border">边框颜色</param>
public OpacityPanel(int alpha, Color back, Color border)
{
this._alpha = alpha;
this._bkcolor = back;
this._bdcolor = border;
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
SetStyle(ControlStyles.Opaque, true);
SetStyle(ControlStyles.UserPaint, true);
SetStyle(ControlStyles.AllPaintingInWmPaint, true);
this.MouseDown += new System.Windows.Forms.MouseEventHandler(MyMouseDown);
this.MouseLeave += new System.EventHandler(MyMouseLeave);
this.MouseMove += new System.Windows.Forms.MouseEventHandler(MyMouseMove);
}
#endregion
#region 私有函数
#region 根据鼠标位置获取鼠标状态
/// <summary>
/// 根据鼠标位置获取鼠标状态
/// </summary>
/// <param name="size"></param>
/// <param name="e"></param>
/// <returns></returns>
private EnumMousePointPosition MousePointPosition(Size size, System.Windows.Forms.MouseEventArgs e)
{
if ((e.X >= -1 * Band) | (e.X <= size.Width) | (e.Y >= -1 * Band) | (e.Y <= size.Height))
{
if (e.X < Band)
{
if (e.Y >= Band && e.Y <= -1 * Band + size.Height)
{
return EnumMousePointPosition.MouseSizeLeft;
}
}
else
{
if (e.X > -1 * Band + size.Width)
{
if (e.Y >= Band && e.Y <= -1 * Band + size.Height)
{
return EnumMousePointPosition.MouseSizeRight;
}
}
else
{
if (e.Y >= Band && e.Y <= -1 * Band + size.Height)
{
return EnumMousePointPosition.MouseDrag;
}
}
}
}
return EnumMousePointPosition.MouseSizeNone;
}
#endregion
#endregion
#region 重载函数
#region 开启 WS_EX_TRANSPARENT,使控件支持透明
/// <summary>
/// 开启 WS_EX_TRANSPARENT,使控件支持透明
/// </summary>
protected override CreateParams CreateParams
{
get
{
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x20; // 开启 WS_EX_TRANSPARENT,使控件支持透明
return cp;
}
}
#endregion
#region 不绘制背景
protected override void OnPaintBackground(PaintEventArgs paintg)
{
//不绘制背景
}
#endregion
#region 绘制图形
protected override void OnPaint(PaintEventArgs e)
{
Graphics g = e.Graphics;
Bitmap bmp = new Bitmap(this.Width, this.Height);
Graphics bufg = Graphics.FromImage(bmp);
bufg.DrawRectangle(new Pen(Color.FromArgb(this._alpha, this._bdcolor)), new Rectangle(0, 0, this.Size.Width, this.Size.Height));
bufg.FillRectangle(new SolidBrush(Color.FromArgb(this._alpha, this._bkcolor)), 0, 0, this.Size.Width, this.Size.Height); //绘制背景
g.DrawImage(bmp, 0, 0);
bufg.Dispose();
bmp.Dispose();
}
#endregion
#endregion
#region 定义事件
#region 鼠标按下事件
private void MyMouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
DownPoint.X = e.X;
DownPoint.Y = e.Y;
CurrPoint.X = e.X;
CurrPoint.Y = e.Y;
}
#endregion
#region 鼠标离开事件
/// <summary>
/// 鼠标离开事件需要改进
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void MyMouseLeave(object sender, EventArgs e)
{
m_MousePointPosition = EnumMousePointPosition.MouseSizeNone;
this.Cursor = Cursors.Arrow;
}
#endregion
#region 鼠标移动事件
private void MyMouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
{
Control lCtrl = (sender as Control);
if (e.Button == MouseButtons.Left)
{
switch (m_MousePointPosition)
{
case EnumMousePointPosition.MouseDrag:
lCtrl.Left = lCtrl.Left + e.X - DownPoint.X;
break;
case EnumMousePointPosition.MouseSizeRight:
lCtrl.Width = lCtrl.Width + e.X - CurrPoint.X;
CurrPoint.X = e.X;
CurrPoint.Y = e.Y; //'记录光标拖动的当前点
break;
case EnumMousePointPosition.MouseSizeLeft:
lCtrl.Left = lCtrl.Left + e.X - DownPoint.X;
lCtrl.Width = lCtrl.Width - (e.X - DownPoint.X);
break;
default:
break;
}
if (lCtrl.Width < MinWidth) lCtrl.Width = MinWidth;
if (lCtrl.Width > this.Width) lCtrl.Width = this.Width;
}
else
{
m_MousePointPosition = MousePointPosition(lCtrl.Size, e); //'判断光标的位置状态
switch (m_MousePointPosition) //'改变光标
{
case EnumMousePointPosition.MouseSizeNone:
this.Cursor = Cursors.Arrow; //'箭头
break;
case EnumMousePointPosition.MouseDrag:
this.Cursor = Cursors.SizeAll; //'四方向
break;
case EnumMousePointPosition.MouseSizeLeft:
this.Cursor = Cursors.SizeWE; //'东西
break;
case EnumMousePointPosition.MouseSizeRight:
this.Cursor = Cursors.SizeWE; //'东西
break;
default:
break;
}
}
}
#endregion
#endregion
}
/// <summary>
/// 光标状态
/// </summary>
enum EnumMousePointPosition
{
MouseSizeNone = 0, //'无
MouseSizeRight = 1, //'拉伸右边框
MouseSizeLeft = 2, //'拉伸左边框
MouseDrag = 9 // '鼠标拖动
}
}
--------------------编程问答-------------------- 自己顶一下，已经开启双缓存，关键是要支持透明，并且拖动改变大小的时候不闪烁。感觉跟开双缓存没多大关系。这个自定义控件很简单：支持透明度，可以拖动位置及改变大小。望高手指点。 --------------------编程问答-------------------- 最近刚开发了一个透明的、可拖动自定义控件，需要联系我qq：1277874734 --------------------编程问答-------------------- --------------------编程问答-------------------- 效果还是不错的，就是存在一些小小的BUG，比如拖动以后就不是半透明的了，而是全透的了。
补充：.NET技术 , 组件/控件开发
