窗体样式使用WS_EX_LAYERED后，无法绘制windows控件的解决办法

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根据一副png图片绘制半透明窗体时，用了WS_EX_LAYERED后当前窗体再也不会处理paint事件，所以所含的子控件是一辈子也不会画出来的，但是这个控件确实存在，而且可以响应事件 。而此时windows画制窗体是使用UpdateLayeredWindow这个api函数的。

其实这个问题，3年前就在csdn网友miky的"笨笨钟"发布后就讨论过了，后来出了一个叫桌面天气秀 的东东也采用类似的技术。那时候我有幸拿到了miky的delphi下实现gdi+半透明窗体的一段代码，因为无法画出button等控件和 几位高人讨论过，这里是当时的讨论情况

http://borland.mblogger.cn/jinjazz/posts/21093.aspx

最终并没有很好的解决办法，而是通过大概如下的方法解决的

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对于按钮，完全可以自己画两个图片然后盖在button上面，通过处理button的enter和leave消息来切换者两个图片来表达按钮状态

对于输入框..这个可以用一个让任何人看了都生气地办法，那就是....两个窗体 ，的确别人就是这么做的

可以用一个空心窗体只显示该显示的控件，然后盖在你的半透明窗体上面，并处理半透明窗体的move事件，让另外一个窗体同步移动或者做其它事情

效果如下：

以下是一些C#代码，Delphi的就不贴了

主Form的代码

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;

namespace WindowsApplication7
... {


public class Form1:System.Windows.Forms.Form
... {
private System.ComponentModel.IContainercomponents;

public Form1()
... {
//
// Windows窗体设计器支持所必需的
//
InitializeComponent();
FormBorderStyle = FormBorderStyle.None;


}

/**/ ///

/// 清理所有正在使用的资源。
///

protected override void Dispose( bool disposing)
... {
if (disposing)
... {
if (components != null )
... {
components.Dispose();
}
}
base .Dispose(disposing);
}

WindowsFormDesignergeneratedcode #region WindowsFormDesignergeneratedcode
/**/ ///

/// 设计器支持所需的方法-不要使用代码编辑器修改
/// 此方法的内容。
///

private void InitializeComponent()
... {
this .button1 = new System.Windows.Forms.Button();
this .SuspendLayout();
//
// button1
//
this .button1.Cursor = System.Windows.Forms.Cursors.Hand;
this .button1.Location = new System.Drawing.Point( 20 , 20 );
this .button1.Name = " button1 " ;
this .button1.Size = new System.Drawing.Size( 113 , 51 );
this .button1.TabIndex = 1 ;
this .button1.Text = " button1 " ;
this .button1.MouseLeave += new System.EventHandler( this .button1_MouseLeave);
this .button1.Click += new System.EventHandler( this .button1_Click);
this .button1.MouseEnter += new System.EventHandler( this .button1_MouseEnter);
//
// Form1
//
this .AutoScaleBaseSize = new System.Drawing.Size( 6 , 14 );
this .ClientSize = new System.Drawing.Size( 184 , 123 );
this .Controls.Add( this .button1);
this .Name = " Form1 " ;
this .StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
this .Text = " Form1 " ;
this .Load += new System.EventHandler( this .Form1_Load);
this .VisibleChanged += new System.EventHandler( this .Form1_VisibleChanged);
this .FormClosed += new System.Windows.Forms.FormClosedEventHandler( this .Form1_FormClosed);
this .MouseDown += new System.Windows.Forms.MouseEventHandler( this .Form1_MouseDown);
this .Move += new System.EventHandler( this .Form1_Move);
this .ResumeLayout( false );

}
#endregion

/**/ ///

/// 应用程序的主入口点。
///

[STAThread]
static void Main()
... {

Application.Run( new Form1());
}


Form2controlFrm = new Form2();
private void button1_Click( object sender,System.EventArgse)
... {
MessageBox.Show(controlFrm,controlFrm.textBox1.Text);

}

protected override CreateParamsCreateParams
... {
get
... {
CreateParamscp = base .CreateParams;
cp.ExStyle |= 0x00080000 ; // ThisformhastohavetheWS_EX_LAYEREDextendedstyle
return cp;
}
}


private void SetStyle1()
... {
Bitmapbm = Image.FromFile( @" Green.png " ) as Bitmap;
Bitmapbm2 = Image.FromFile( @" btn.png " ) as Bitmap;

Graphicsg = Graphics.FromImage(bm);
g.DrawImage(bm2, 20 , 20 , new Rectangle( 0 , 0 , 90 , 50 ),GraphicsUnit.Pixel);

g.DrawString( " byjinjazz " , new Font( " Ariel " , 9 ,FontStyle.Bold), new SolidBrush(Color.Black), new PointF( 40 , 50 ));

this .SetBitmap(bm, 255 );
}
private void SetStyle2()
... {
Bitmapbm = Image.FromFile( @" Green.png " ) as Bitmap;
Bitmapbm2 = Image.FromFile( @" btn.png " ) as Bitmap;

Graphicsg = Graphics.FromImage(bm);
g.DrawImage(bm2, 15 , 15 , new Rectangle( 7 , 140 , 100 , 50 ),GraphicsUnit.Pixel);

g.DrawString( " byjinjazz " , new Font( " Ariel " , 9 ,FontStyle.Bold), new SolidBrush(Color.Black), new PointF( 40 , 50 ));

this .SetBitmap(bm, 255 );
}


private void Form1_Load( object sender,System.EventArgse)
... {

controlFrm.Show();
SetStyle1();

// this.TopMost=true;
controlFrm.TopMost = true ;
}

private void button1_MouseEnter( object sender,EventArgse)
... {

SetStyle2();
}
private void button1_MouseLeave( object sender,EventArgse)
... {
SetStyle1();
}

public void SetBitmap(Bitmapbitmap, byte opacity)
... {
if (bitmap.PixelFormat != PixelFormat.Format32bppArgb)
throw new ApplicationException( " Thebitmapmustbe32pppwithalpha-channel. " );

// Theideiaofthisisverysimple,
// 1.CreateacompatibleDCwithscreen;
// 2.Selectthebitmapwith32bppwithalpha-channelinthecompatibleDC;
// 3.CalltheUpdateLayeredWindow.

IntPtrscreenDc = Win32.GetDC(IntPtr.Zero);
IntPtrmemDc = Win32.CreateCompatibleDC(screenDc);
IntPtrhBitmap = IntPtr.Zero;
IntPtroldBitmap = IntPtr.Zero;

try
... {
hBitmap = bitmap.GetHbitmap(Color.FromArgb( 0 )); // grabaGDIhandlefromthisGDI+bitmap
oldBitmap = Win32.SelectObject(memDc,hBitmap);

Win32.Sizesize = new Win32.Size(bitmap.Width,bitmap.Height);
Win32.PointpointSource = new Win32.Point( 0 , 0 );
Win32.PointtopPos = new Win32.Point(Left,Top);
Win32.BLENDFUNCTIONblend = new Win32.BLENDFUNCTION();
blend.BlendOp = Win32.AC_SRC_OVER;
blend.BlendFlags = 0 ;
blend.SourceConstantAlpha = opacity;
blend.AlphaFormat = Win32.AC_SRC_ALPHA;

Win32.UpdateLayeredWindow(Handle,screenDc, ref topPos, ref size,memDc, ref pointSource, 0 , ref blend,Win32.ULW_ALPHA);
}
finally
... {
Win32.ReleaseDC(IntPtr.Zero,screenDc);
if (hBitmap != IntPtr.Zero)
... {
Win32.SelectObject(memDc,oldBitmap);
// Windows.DeleteObject(hBitmap); // ThedocumentationsaysthatwehavetousetheWindows.DeleteObject...butsincethereisnosuchmethodIusethenormalDeleteObjectfromWin32GDIandit'sworkingfinewithoutanyresourceleak.
Win32.DeleteObject(hBitmap);
}
Win32.DeleteDC(memDc);
}
}


private System.Windows.Forms.Buttonbutton1;

private void Form1_MouseDown( object sender,System.Windows.Forms.MouseEventArgse)
... {
Win32.ReleaseCapture();
Win32.SendMessage( this .Handle.ToInt32(),Win32.WM_SysCommand,Win32.SC_MOVE, 0 );
}
ht