.NET Windows Form 改变窗体类名（Class Name）有多难？

研究WinForm的东西，是我的一个个人兴趣和爱好，以前做的项目，多与WinForm相关，然而这几年，项目都与WinForm没什么关系了，都转为ASP.NET MVC与WPF了。关于今天讨论的这个问题，以前也曾深入研究过，只是最近有朋友问到这个问题，就再挖挖这个坟（坑）。

一、类名是啥？

打开神器SPY++，VS2013 在【工具】菜单里：

VS2013之前的VS版本，在【开始菜单】里：

打开SPY++，点击标注的按钮，

在打开的窗口上，把雷达按钮拖到你想查看的窗口，就可以看到它的类名了，下面就是QQ的类名：

再看看.NET WinForm的窗体类名：

一大串啊，有没有，我不想这样，我想要一个有个性的、简单的类名，咋办？

二、 不是有个CreateParams属性吗？

作为一个有多年WinForm开发经验的程序猿，这有啥难的，WinForm的控件不是都有个CreateParams属性吗？里面可以不是就可以设置窗口类名吗？看看：

真的有，这不就简单了嘛，动手，于是有下面代码：

public partial class FormMain : Form {  public FormMain()  {   InitializeComponent();  }  protected override CreateParams CreateParams  {   get   {    CreateParams createParams = base.CreateParams;    createParams.ClassName = "Starts2000.Window"; //这就是我想要的窗体类名。    return createParams;   }  } } 

编译，运行，结果却是这样的：

泥煤啊，这是什么啊，翻~墙，一通谷歌，原来类名使用前都需要注册啊，难道微软只注册了自己的类名，我个性化的他就不帮我注册，那我就自己注册吧，坑爹的微软啊。

三、注册一个窗口类名吧

注册窗口类名需要用到Windows API函数了，用C#进行P/Invoke？太麻烦了，做了这么多年的WinForm开发，我可是练了《 葵花宝典 （C++/CLI）》的，只是因为没自宫，所以没大成，不过，简单用用还是可以的。

创建一个C++空项目，设置项目属性-配置属性-常规，如下图：

于是有了下面的代码：

1. FormEx.h

#pragma once #include <Windows.h> #include <vcclr.h>  #define CUSTOM_CLASS_NAME  L"Starts2000.Window"  namespace Starts2000 {  namespace WindowsClassName  {   namespace Core   {    using namespace System;    using namespace System::Windows::Forms;    using namespace System::Runtime::InteropServices;     private delegate LRESULT WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);     public ref class FormEx :     public Form    {    public:     static FormEx();     FormEx();    private:     static LRESULT WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);     static void ProcessExit(Object^ sender, EventArgs^ e);    };   }  } }

2. FormEx.cpp

#include "FormEx.h"  namespace Starts2000 {  namespace WindowsClassName  {   namespace Core   {    static FormEx::FormEx()    {     WNDCLASSEX wc;     Starts2000::WindowsClassName::Core::WndProc ^windowProc =      gcnew Starts2000::WindowsClassName::Core::WndProc(FormEx::WndProc);     pin_ptr<Starts2000::WindowsClassName::Core::WndProc^> pWindowProc = &windowProc;      ZeroMemory(&wc, sizeof(WNDCLASSEX));     wc.cbSize = sizeof(WNDCLASSEX);     wc.style = CS_DBLCLKS;     wc.lpfnWndProc = reinterpret_cast<WNDPROC>(Marshal::GetFunctionPointerForDelegate(windowProc).ToPointer());     wc.hInstance = GetModuleHandle(NULL);     wc.hCursor = LoadCursor(NULL, IDC_ARROW);     wc.hbrBackground = (HBRUSH)COLOR_WINDOW; //(HBRUSH)GetStockObject(HOLLOW_BRUSH);     wc.lpszClassName = CUSTOM_CLASS_NAME;      ATOM classAtom = RegisterClassEx(&wc);     DWORD lastError = GetLastError();     if (classAtom == 0 && lastError != ERROR_CLASS_ALREADY_EXISTS)     {      throw gcnew ApplicationException("Register window class failed!");     }      System::AppDomain::CurrentDomain->ProcessExit += gcnew System::EventHandler(FormEx::ProcessExit);    }     FormEx::FormEx() : Form()    {    }     LRESULT FormEx::WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)    {     System::Windows::Forms::Message message = System::Windows::Forms::Message::Create((IntPtr)hWnd,      (int)msg, (IntPtr)((void*)wParam), (IntPtr)((void*)lParam));     System::Diagnostics::Debug::WriteLine(message.ToString());     return DefWindowProc(hWnd, msg, wParam, lParam);    }     void FormEx::ProcessExit(Object^ sender, EventArgs^ e)    {     UnregisterClass(CUSTOM_CLASS_NAME, GetModuleHandle(NULL));    }   }  } }

3. 创建一个C# WinForm项目，引用上面创建的C++/CLI项目生成的DLL，代码跟最开始的区别不大。

public partial class FormMain : /*Form*/ FormEx {  public FormMain()  {   InitializeComponent();  }  protected override CreateParams CreateParams  {   get   {    CreateParams createParams = base.CreateParams;    createParams.ClassName = "Starts2000.Window"; //这就是我想要的窗体类名。    return createParams;   }  } } 

编译，运行，结果却仍然是这样的：

泥煤啊，微软到底干了什么，我只是想搞点小玩意，满足下我的虚荣心，你竟然……，心中千万头“羊驼”奔腾而过。

没办法了，微软不都开源了吗，也不需要反编译了，直接下源代码看吧。

四、也不反编译了，直接找源代码看吧

在微软的网站（ http://referencesource.microsoft.com/ ）Down下代码，从Form→ContainerControl→ScrollableControl→Control，在Control里找到NativeWindow，再在NativeWindow里面找到了WindowClass，在WindowClass里找到了坑爹的RegisterClass方法，恍然大悟了，有没有，具体看代码，我加了注释。

private void RegisterClass() {  NativeMethods.WNDCLASS_D wndclass = new NativeMethods.WNDCLASS_D();  if (userDefWindowProc == IntPtr.Zero) {   string defproc = (Marshal.SystemDefaultCharSize == 1 ? "DefWindowProcA" : "DefWindowProcW");   userDefWindowProc = UnsafeNativeMethods.GetProcAddress(new HandleRef(null, UnsafeNativeMethods.GetModuleHandle("user32.dll")), defproc);   if (userDefWindowProc == IntPtr.Zero) {    throw new Win32Exception();   }  }  string localClassName = className;  if (localClassName == null) {  //看看是否自定义了classnName，就是我们在 CreateParams ClassName设置的值。   // If we don't use a hollow brush here, Windows will "pre paint" us with COLOR_WINDOW which   // creates a little bit if flicker.  This happens even though we are overriding wm_erasebackgnd.   // Make this hollow to avoid all flicker.   //   wndclass.hbrBackground = UnsafeNativeMethods.GetStockObject(NativeMethods.HOLLOW_BRUSH); //(IntPtr)(NativeMethods.COLOR_WINDOW + 1);   wndclass.style = classStyle;   defWindowProc = userDefWindowProc;   localClassName = "Window." + Convert.ToString(classStyle, 16);   hashCode = 0;  }  else {   //坑爹的就在这里了   NativeMethods.WNDCLASS_I wcls = new NativeMethods.WNDCLASS_I();   /*注意下面这句代码，特别注意 NativeMethods.NullHandleRef，MSDN说明：    * BOOL WINAPI GetClassInfo(    * _In_opt_ HINSTANCE  hInstance,    * _In_  LPCTSTR lpClassName,    * _Out_ LPWNDCLASS lpWndClass    *  );    * hInstance [in, optional]    *  Type: HINSTANCE    *  A handle to the instance of the application that created the class.     * To retrieve information about classes defined by the system (such as buttons or list boxes),    * set this parameter to NULL.    * 就是说，GetClassInfo 的第一个参数为 NULL(NativeMethods.NullHandleRef)的时候，只有系统注册的 ClassName    * 才会返回 True，所以当我们设置了CreateParams ClassName的值后，只要设置的不是系统注册的 ClassName，都会    * 抛出后面的 Win32Exception 异常，泥煤啊。   */   bool ok = UnsafeNativeMethods.GetClassInfo(NativeMethods.NullHandleRef, className, wcls);   int error = Marshal.GetLastWin32Error();   if (!ok) {    throw new Win32Exception(error, SR.GetString(SR.InvalidWndClsName));   }   wndclass.style = wcls.style;   wndclass.cbClsExtra = wcls.cbClsExtra;   wndclass.cbWndExtra = wcls.cbWndExtra;   wndclass.hIcon = wcls.hIcon;   wndclass.hCursor = wcls.hCursor;   wndclass.hbrBackground = wcls.hbrBackground;   wndclass.lpszMenuName = Marshal.PtrToStringAuto(wcls.lpszMenuName);   localClassName = className;   defWindowProc = wcls.lpfnWndProc;   hashCode = className.GetHashCode();  }  // Our static data is different for different app domains, so we include the app domain in with  // our window class name.  This way our static table always matches what Win32 thinks.  //   windowClassName = GetFullClassName(localClassName);  windowProc = new NativeMethods.WndProc(this.Callback);  wndclass.lpfnWndProc = windowProc;  wndclass.hInstance = UnsafeNativeMethods.GetModuleHandle(null);  wndclass.lpszClassName = windowClassName;  short atom = UnsafeNativeMethods.RegisterClass(wndclass);  if (atom == 0) {   int err = Marshal.GetLastWin32Error();   if (err == NativeMethods.ERROR_CLASS_ALREADY_EXISTS) {    // Check to see if the window class window    // proc points to DefWndProc.  If it does, then    // this is a class from a rudely-terminated app domain    // and we can safely reuse it.  If not, we've got    // to throw.    NativeMethods.WNDCLASS_I wcls = new NativeMethods.WNDCLASS_I();    bool ok = UnsafeNativeMethods.GetClassInfo(new HandleRef(null, UnsafeNativeMethods.GetModuleHandle(null)), windowClassName, wcls);    if (ok && wcls.lpfnWndProc == NativeWindow.UserDefindowProc) {     // We can just reuse this class because we have marked it     // as being a nop in another domain.  All we need to do is call SetClassLong.     // Only one problem:  SetClassLong takes an HWND, which we don't have.  That leaves     // us with some tricky business. First, try this the easy way and see     // if we can simply unregister and re-register the class.  This might     // work because the other domain shutdown would have posted WM_CLOSE to all     // the windows of the class.     if (UnsafeNativeMethods.UnregisterClass(windowClassName, new HandleRef(null, UnsafeNativeMethods.GetModuleHandle(null)))) {      atom = UnsafeNativeMethods.RegisterClass(wndclass);      // If this fails, we will always raise the first err above.  No sense exposing our twiddling.     }     else {      // This is a little harder.  We cannot reuse the class because it is      // already in use.  We must create a new class.  We bump our domain qualifier      // here to account for this, so we only do this expensive search once for the      // domain.        do {       domainQualifier++;       windowClassName = GetFullClassName(localClassName);       wndclass.lpszClassName = windowClassName;       atom = UnsafeNativeMethods.RegisterClass(wndclass);      } while (atom == 0 && Marshal.GetLastWin32Error() == NativeMethods.ERROR_CLASS_ALREADY_EXISTS);     }    }   }   if (atom == 0) {    windowProc = null;    throw new Win32Exception(err);   }  }  registered = true; } 

五、吓尿了！自己动手，丰衣足食

看到微软的源码后，只能表示尿了，不可能继承Form实现自定义类名了，那么就自己动手，丰衣足食吧，还记得上面的C++/CLI代码吧，简单的加一些内容，就可以实现我们自定义窗口类名的愿望了，代码如下：

1. CustomForm.h

#pragma once  #include <Windows.h> #include <vcclr.h>  #define CUSTOM_CLASS_NAME  L"Starts2000.Window"  namespace Starts2000 {  namespace WindowsClassName  {   namespace Core   {    using namespace System;    using namespace System::Windows::Forms;    using namespace System::Runtime::InteropServices;     private delegate LRESULT WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);     public ref class CustomForm    {    public:     static CustomForm();     CustomForm();     CustomForm(String ^caption);     ~CustomForm();     void Create();     void Show();    private:     String ^_caption;     HWND _hWnd;     static GCHandle _windowProcHandle;     static LRESULT WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);     static void ProcessExit(Object^ sender, EventArgs^ e);    };   }  } }

2. CustomForm.cpp

#include "CustomForm.h"  namespace Starts2000 {  namespace WindowsClassName  {   namespace Core   {    static CustomForm::CustomForm()    {     WNDCLASSEX wc;     Starts2000::WindowsClassName::Core::WndProc ^windowProc =      gcnew Starts2000::WindowsClassName::Core::WndProc(CustomForm::WndProc);     _windowProcHandle = GCHandle::Alloc(windowProc);      ZeroMemory(&wc, sizeof(WNDCLASSEX));     wc.cbSize = sizeof(WNDCLASSEX);     wc.style = CS_DBLCLKS;     wc.lpfnWndProc = reinterpret_cast<WNDPROC>(Marshal::GetFunctionPointerForDelegate(windowProc).ToPointer());     wc.hInstance = GetModuleHandle(NULL);     wc.hCursor = LoadCursor(NULL, IDC_ARROW);     wc.hbrBackground = (HBRUSH)COLOR_WINDOW; //(HBRUSH)GetStockObject(HOLLOW_BRUSH);     wc.lpszClassName = CUSTOM_CLASS_NAME;      ATOM classAtom = RegisterClassEx(&wc);     DWORD lastError = GetLastError();     if (classAtom == 0 && lastError != ERROR_CLASS_ALREADY_EXISTS)     {      throw gcnew ApplicationException("Register window class failed!");     }      System::AppDomain::CurrentDomain->ProcessExit += gcnew System::EventHandler(CustomForm::ProcessExit);    }     CustomForm::CustomForm() : _caption("Starts2000 Custom ClassName Window")    {    }     CustomForm::CustomForm(String ^caption) : _caption(caption)    {    }     CustomForm::~CustomForm()    {     if (_hWnd)     {      DestroyWindow(_hWnd);     }    }     void CustomForm::Create()    {     DWORD styleEx = 0x00050100;     DWORD style = 0x17cf0000;      pin_ptr<const wchar_t> caption = PtrToStringChars(_caption);      _hWnd = CreateWindowEx(styleEx, CUSTOM_CLASS_NAME, caption, style,      CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,      NULL, NULL, GetModuleHandle(NULL), NULL);     if (_hWnd == NULL)     {      throw gcnew ApplicationException("Create window failed! Error code:" + GetLastError());     }    }     void CustomForm::Show()    {     if (_hWnd)     {      ShowWindow(_hWnd, SW_NORMAL);     }    }     LRESULT CustomForm::WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)    {     System::Windows::Forms::Message message = System::Windows::Forms::Message::Create((IntPtr)hWnd,      (int)msg, (IntPtr)((void*)wParam), (IntPtr)((void*)lParam));     System::Diagnostics::Debug::WriteLine(message.ToString());          if (msg == WM_DESTROY)     {      PostQuitMessage(0);      return 0;     }      return DefWindowProc(hWnd, msg, wParam, lParam);    }     void CustomForm::ProcessExit(Object^ sender, EventArgs^ e)    {     UnregisterClass(CUSTOM_CLASS_NAME, GetModuleHandle(NULL));     if (CustomForm::_windowProcHandle.IsAllocated)     {      CustomForm::_windowProcHandle.Free();     }    }   }  } }

最后仍然用我们熟悉的C#来调用：

using System; using System.Windows.Forms; using Starts2000.WindowsClassName.Core; namespace Starts2000.WindowClassName.Demo {  static class Program  {   /// <summary>   /// 应用程序的主入口点。   /// </summary>   [STAThread]   static void Main()   {    //Application.EnableVisualStyles();    //Application.SetCompatibleTextRenderingDefault(false);    //Application.Run(new FormMain());    CustomForm form = new CustomForm();    form.Create();    form.Show();    Application.Run();   }  } } 

编译，运行，拿出神器SPY++看一看：

目标终于达成。

最后，所有代码的下载（项目使用的是VS2013编译、调试，不保证其他版本VS能正常编译）：猛击我。