在扩展玻璃框架中绘制文本框（不使用 WPF）

Question

我正在尝试在表单的扩展玻璃框架上绘制一个文本框。我不会描述这个技术，它是众所周知的。对于那些还没有听说过的人来说，这是一个示例： http:// /www.danielmoth.com/Blog/Vista-Glass-In-C.aspx

问题是，在这个玻璃框架上绘图很复杂。由于黑色被认为是 0-alpha 颜色，因此任何黑色都会消失。

显然有一些方法可以解决这个问题：绘制复杂的 GDI+ 形状不受这种 alpha 的影响。例如，此代码可用于在玻璃上绘制标签（注意：使用 GraphicsPath 代替 DrawString 是为了解决可怕的 ClearType 问题）：

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);
    }
}

同样，这种方法可用于在玻璃区域上创建容器。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？ 经过大量谷歌搜索后，我想出了以下解决方案：

• 子类化 TextBox 的 OnPaint 方法。这是可能的，尽管我无法让它正常工作。它应该涉及画一些我还不知道怎么做的神奇的东西。
• 制作我自己的自定义 TextBox，可能在 TextBoxBase 上。如果有人有好的、有效且可行的示例，并且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可能看起来很奇怪，但我可以忍受。如果有人知道如何从 Graphics 对象正确实现该方法，请告诉我。我个人不喜欢，但这似乎是迄今为止最好的解决方案。老实说，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

注意：如果我成功使用 BufferedPaint 方法，我发誓 s/o我将制作一个简单的 DLL，其中包含可在玻璃上绘制的所有常见 Windows 窗体控件。

Answer 1

不久前我花了一些时间讨论这个话题。基本上你需要的是一个透明的文本框。我最初的方法是使用 codeproject AlphaBlendTextBox - .NET 的透明/半透明文本框。但我在该控制方面遇到了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，它仅适用于 Windows XP 及更高版本。为了使该控件的行为类似于单行文本框，请将 RichTextBox.Multiline 设置为 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;
        }
    }
}