在没有WPF的扩展玻璃框中绘制文本框

Question

我想在窗体的扩展玻璃框上绘制文本框。我不会描述这种技术，这是众所周知的。以下是一些没有听说过的例子：http://www.danielmoth.com/Blog/Vista-Glass-In-C.aspx

问题是，画这个玻璃框很复杂。由于黑色被认为是0-alpha颜色，黑色消失。

有明显的方法来解决这个问题：绘制复杂的GDI +形状不受这个alpha-ness的影响。例如，该代码可以被用来绘制在玻璃上的标签（注：GraphicsPath为了避开可怕的ClearType问题是用来代替DrawString）：

public class GlassLabel : Control 
{ 
    public GlassLabel() 
    { 
     this.BackColor = Color.Black; 
    } 

    protected override void OnPaint(PaintEventArgs e) 
    { 
     GraphicsPath font = new GraphicsPath(); 

     font.AddString(
      this.Text, 
      this.Font.FontFamily, 
      (int)this.Font.Style, 
      this.Font.Size, 
      Point.Empty, 
      StringFormat.GenericDefault); 

     e.Graphics.SmoothingMode = SmoothingMode.HighQuality; 
     e.Graphics.FillPath(new SolidBrush(this.ForeColor), font); 
    } 
} 

类似地，这样的方法可以用于在玻璃区域创建一个容器。请注意使用多边形而不是矩形 - 使用矩形时，其黑色部分被视为alpha。

public class GlassPanel : Panel 
{ 
    public GlassPanel() 
    { 
     this.BackColor = Color.Black; 
    } 

    protected override void OnPaint(PaintEventArgs e) 
    { 
     Point[] area = new Point[] 
      { 
       new Point(0, 1), 
       new Point(1, 0), 
       new Point(this.Width - 2, 0), 
       new Point(this.Width - 1, 1), 
       new Point(this.Width -1, this.Height - 2), 
       new Point(this.Width -2, this.Height-1), 
       new Point(1, this.Height -1), 
       new Point(0, this.Height - 2) 
      }; 

     Point[] inArea = new Point[] 
      { 
       new Point(1, 1), 
       new Point(this.Width - 1, 1), 
       new Point(this.Width - 1, this.Height - 1), 
       new Point(this.Width - 1, this.Height - 1), 
       new Point(1, this.Height - 1) 
      }; 

     e.Graphics.FillPolygon(new SolidBrush(Color.FromArgb(240, 240, 240)), inArea); 
     e.Graphics.DrawPolygon(new Pen(Color.FromArgb(55, 0, 0, 0)), area); 

     base.OnPaint(e); 
    } 
} 

现在我的问题是：如何绘制文本框？ 经过大量的谷歌搜索，我想出了以下解决方案：

• 子类文本框的OnPaint方法。这是可能，虽然我无法让它正常工作。它应该涉及绘制一些我不知道该怎么做的魔术。
• 制作我自己的自定义TextBox，或许在TextBoxBase。如果有人有好，有效和工作的例子，并认为这可能是一个很好的整体解决方案，请告诉我。
• 使用BufferedPaintSetAlpha。 （http://msdn.microsoft.com/en-us/library/ms649805.aspx）。这种方法的缺点可能是文本框的角落看起来很古怪，但我可以忍受。如果有人知道如何从Graphics对象中正确实现该方法，请告诉我。我个人不这样做，但这似乎是迄今为止最好的解决方案。说实话，我发现了一篇很棒的C++文章，但我懒得转换它。 http://weblogs.asp.net/kennykerr/archive/2007/01/23/controls-and-the-desktop-window-manager.aspx

注：如果我曾经与BufferedPaint方法成功了，我发誓S/O，我会做一个简单的DLL与所有常见的Windows窗体控件可绘制在玻璃上。

Answer 1

前段时间我在这个话题上花了一些时间。基本上你需要的是一个透明的文本框。我最初的做法是使用codeproject AlphaBlendTextBox - A transparent/translucent textbox for .NET。但是我有一些难以解决的问题。一段时间后，我找到了所需的解决方案，它只能在Windows XP及更高版本上运行。以及让这个控件的行为像单行文本框设置RichTextBox.Multiline为false。

// Source: 
// http://www.dotnetjunkies.com/WebLog/johnwood/archive/2006/07/04/transparent_richtextbox.aspx 

// It seems there are 4 versions of the RichEdit control out there - when I'm talking about the 
// RichEdit control, I'm talking about the C DLL that either comes with Windows or some version 
// of Office. The files are named either RICHEDXX.DLL (XX is the version number), or MSFTEDIT.DLL 
// and they're in the System32 folder. 

// .Net RichTextBox control is bound to version 2. The biggest problem with this version (at least 
// for me) is that it does not render properly if you try to make the window transparent. Later versions, 
// however, do. 

// We can fix that. If you create a control deriving from the original RichTextBox control, but overriding 
// the CreateParams property, you can put in a new Windows class name (this is the window class name, 
// nothing to do with classes in the C# sense). This effectively gives us a free upgrade. When the .Net 
// RichTextBox control instantiates, it will now use the latest RichEdit control and not the old, archaic, 
// version 2. 

// There are other benefits too - version 3 and beyond of the RichEdit control support quite an extensive 
// array of layout features, such as tables and full text justification. This is the version of the RichEdit 
// that WordPad uses in Windows XP. To really see what it's capable of displaying you can create documents in 
// Word and save them in RTF, load these into the new RichEdit and in a lot of cases it'll look identical, 
// it's that powerful. A full list of features can be found here: 
// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/shellcc/platform/commctls/richedit/richeditcontrols/aboutricheditcontrols.asp 

// There are a couple of caveats: 
// 
// 1. The control that this is bound to was shipped with Windows XP, and so this code won't work in 
// Windows 2000 or earlier. 
// 
// 2. The RichTextBox control in C# only knows about version 2, so the interface doesn't include 
// all the new features. You can wrap a few of the features yourself through new methods on the 
// RichEdit class. 

using System; 
using System.Runtime.InteropServices; 
using System.Windows.Forms; 

internal class RichEdit : RichTextBox 
{ 

    [DllImport("kernel32.dll", CharSet = CharSet.Auto)] 
    private static extern IntPtr LoadLibrary(string lpFileName); 

    protected override CreateParams CreateParams 
    { 
     get 
     { 
      CreateParams parameters = base.CreateParams; 
      if (LoadLibrary("msftedit.dll") != IntPtr.Zero) 
      { 
       parameters.ExStyle |= 0x020; // transparent 
       parameters.ClassName = "RICHEDIT50W"; 
      } 
      return parameters; 
     } 
    } 
}