CreateWindowEx和RegisterClass C#

Question

我想创建一个新类，然后显示一个包含指定类的窗口。为此，我编写了以下代码：

    namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        [DllImport("user32.dll")]
        static extern bool UpdateWindow(IntPtr hWnd);

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
        [DllImport("user32.dll", SetLastError = true, EntryPoint = "CreateWindowEx")]
        public static extern IntPtr CreateWindowEx(
           int dwExStyle,
           string lpClassName,
           string lpWindowName,
           int dwStyle,
           int x,
           int y,
           int nWidth,
           int nHeight,
           IntPtr hWndParent,
           IntPtr hMenu,
           IntPtr hInstance,
           IntPtr lpParam);
        [System.Runtime.InteropServices.DllImport("user32.dll", SetLastError = true)]
        static extern System.UInt16 RegisterClassW(
            [System.Runtime.InteropServices.In] ref WNDCLASSEX lpWndClass
        );
        struct WNDCLASSEX
        {
            [MarshalAs(UnmanagedType.U4)]
            public int cbSize;
            [MarshalAs(UnmanagedType.U4)]
            public int style;
            public IntPtr lpfnWndProc; // not WndProc
            public int cbClsExtra;
            public int cbWndExtra;
            public IntPtr hInstance;
            public IntPtr hIcon;
            public IntPtr hCursor;
            public IntPtr hbrBackground;
            public string lpszMenuName;
            public string lpszClassName;
            public IntPtr hIconSm;
        }
        [DllImport("user32.dll")]
        static extern IntPtr DefWindowProc(IntPtr hWnd, uint uMsg, IntPtr wParam, IntPtr lParam);

        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {


        }

        private void button1_Click(object sender, EventArgs e)
        {
            WNDCLASSEX wind_class = new WNDCLASSEX();
            wind_class.cbSize = Marshal.SizeOf(typeof(WNDCLASSEX));
            wind_class.style = 0x00020000;
            wind_class.hbrBackground = (IntPtr) 5;
            wind_class.cbClsExtra = 0;
            wind_class.cbWndExtra = 0;
            wind_class.hInstance = Marshal.GetHINSTANCE(GetType().Module);
            wind_class.hIcon = this.Icon.Handle;
            wind_class.hCursor = IntPtr.Zero;
            wind_class.lpszMenuName = string.Empty;
            wind_class.lpszClassName = "MyClass";
            wind_class.lpfnWndProc = DefWindowProc(IntPtr.Zero, 0, IntPtr.Zero, IntPtr.Zero);
            RegisterClassW(ref wind_class);
            IntPtr lolo = CreateWindowEx(0, "MyClass", "MyClass",0,0,0,30,40,IntPtr.Zero,IntPtr.Zero,IntPtr.Zero,IntPtr.Zero);
            ShowWindow(lolo, 1);
            UpdateWindow(lolo);
        }
    }
}

但是它不能正常工作。它不会显示窗口。当我用我的类名搜索Spy++时，它找不到任何结果。

我在网页上搜索，在我的代码中做了一些编辑，但它们不起作用。

我的问题在哪里!？

致以问候。

Answer 1

普通的Win32在Win32 C中毫无乐趣，在.NET中也没有那么有趣，但不管怎样，它在极少数情况下可能会有用。下面是一个C#类，它应该可以执行您想要的操作。首先，对你的软件做一个一般性的评论。在Win32中，您应该始终检查系统调用的返回代码，并在出现错误时调用GetLastError()以获取有关失败的更详细信息。如果您检查了RegisterClass函数的结果，但它失败了，那么您就会知道，如果没有修复它，继续下去是没有用的。

下面是一个类，它可以用作进一步研究的模板，并且应该成功注册并创建一个可调整大小的窗口。此外，一些简单的操作，如doubleclick，是在自定义窗口过程中处理的。对于代码的某些部分，功劳归功于this站点，它是我在web上找到的为数不多的几个提供一些工作的站点之一。

CreateWindowEx很棘手，因为您不能将字符串作为类名，而必须放入RegisterClassEx的结果。使用的常量主要在C头文件winuser.h中找到。为了能够用这种方法做一些有用的事情，主要的绘画必须“手工”完成，这是一项繁琐而乏味的工作，需要适当地操纵设备上下文。当然，所有这些都不会在下面的示例中显示出来。可以例如从Windows窗体按钮点击来调用类的"create“方法。当然，命名空间名称是任意选择的。WinForm项目是32位的x86，.NET 4.0。

玩得开心!

namespace Win32FromForms
{
    delegate IntPtr WndProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);

    class Win32Window
    {
        const UInt32 WS_OVERLAPPEDWINDOW = 0xcf0000;
        const UInt32 WS_VISIBLE = 0x10000000;
        const UInt32 CS_USEDEFAULT = 0x80000000;
        const UInt32 CS_DBLCLKS = 8;
        const UInt32 CS_VREDRAW = 1;
        const UInt32 CS_HREDRAW = 2;
        const UInt32 COLOR_WINDOW = 5;
        const UInt32 COLOR_BACKGROUND = 1;
        const UInt32 IDC_CROSS = 32515;
        const UInt32 WM_DESTROY = 2;
        const UInt32 WM_PAINT = 0x0f;
        const UInt32 WM_LBUTTONUP = 0x0202;
        const UInt32 WM_LBUTTONDBLCLK = 0x0203;

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        struct WNDCLASSEX
        {
            [MarshalAs(UnmanagedType.U4)]
            public int cbSize;
            [MarshalAs(UnmanagedType.U4)]
            public int style;
            public IntPtr lpfnWndProc; 
            public int cbClsExtra;
            public int cbWndExtra;
            public IntPtr hInstance;
            public IntPtr hIcon;
            public IntPtr hCursor;
            public IntPtr hbrBackground;
            public string lpszMenuName;
            public string lpszClassName;
            public IntPtr hIconSm;
        }


        private WndProc delegWndProc = myWndProc;

        [DllImport("user32.dll")]
        static extern bool UpdateWindow(IntPtr hWnd);

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

        [System.Runtime.InteropServices.DllImport("user32.dll", SetLastError = true)]
        static extern bool DestroyWindow(IntPtr hWnd);


        [DllImport("user32.dll", SetLastError = true, EntryPoint = "CreateWindowEx")]
        public static extern IntPtr CreateWindowEx(
           int dwExStyle,
           UInt16 regResult,
           //string lpClassName,
           string lpWindowName,
           UInt32 dwStyle,
           int x,
           int y,
           int nWidth,
           int nHeight,
           IntPtr hWndParent,
           IntPtr hMenu,
           IntPtr hInstance,
           IntPtr lpParam);

        [DllImport("user32.dll", SetLastError = true, EntryPoint = "RegisterClassEx")]
        static extern System.UInt16 RegisterClassEx([In] ref WNDCLASSEX lpWndClass);

        [DllImport("kernel32.dll")]
        static extern uint GetLastError();

        [DllImport("user32.dll")]
        static extern IntPtr DefWindowProc(IntPtr hWnd, uint uMsg, IntPtr wParam, IntPtr lParam);

        [DllImport("user32.dll")]
        static extern void PostQuitMessage(int nExitCode);

        //[DllImport("user32.dll")]
        //static extern sbyte GetMessage(out MSG lpMsg, IntPtr hWnd, uint wMsgFilterMin,
        //   uint wMsgFilterMax);

        [DllImport("user32.dll")]
        static extern IntPtr LoadCursor(IntPtr hInstance, int lpCursorName);

        [DllImport("user32.dll")]
        static extern bool TranslateMessage([In] ref MSG lpMsg);

        [DllImport("user32.dll")]
        static extern IntPtr DispatchMessage([In] ref MSG lpmsg);    


        internal bool create()
        {
            WNDCLASSEX wind_class = new WNDCLASSEX();
            wind_class.cbSize = Marshal.SizeOf(typeof(WNDCLASSEX));
            wind_class.style = (int)(CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS ) ; //Doubleclicks are active
            wind_class.hbrBackground = (IntPtr) COLOR_BACKGROUND  +1 ; //Black background, +1 is necessary
            wind_class.cbClsExtra = 0;
            wind_class.cbWndExtra = 0;
            wind_class.hInstance = Marshal.GetHINSTANCE(this.GetType().Module); ;// alternative: Process.GetCurrentProcess().Handle;
            wind_class.hIcon = IntPtr.Zero;
            wind_class.hCursor = LoadCursor(IntPtr.Zero, (int)IDC_CROSS);// Crosshair cursor;
            wind_class.lpszMenuName = null;
            wind_class.lpszClassName = "myClass";
            wind_class.lpfnWndProc = Marshal.GetFunctionPointerForDelegate(delegWndProc);
            wind_class.hIconSm = IntPtr.Zero;
            ushort regResult = RegisterClassEx(ref wind_class);

            if (regResult == 0)
            {
                uint error = GetLastError();
                return false;
            }
            string wndClass = wind_class.lpszClassName;

            //The next line did NOT work with me! When searching the web, the reason seems to be unclear! 
            //It resulted in a zero hWnd, but GetLastError resulted in zero (i.e. no error) as well !!??)
            //IntPtr hWnd = CreateWindowEx(0, wind_class.lpszClassName, "MyWnd", WS_OVERLAPPEDWINDOW | WS_VISIBLE, 0, 0, 30, 40, IntPtr.Zero, IntPtr.Zero, wind_class.hInstance, IntPtr.Zero);

            //This version worked and resulted in a non-zero hWnd
            IntPtr hWnd = CreateWindowEx(0, regResult, "Hello Win32", WS_OVERLAPPEDWINDOW | WS_VISIBLE, 0, 0, 300, 400, IntPtr.Zero, IntPtr.Zero, wind_class.hInstance, IntPtr.Zero);

            if (hWnd == ((IntPtr)0))
            {
                uint error = GetLastError();
                return false;
            }
            ShowWindow(hWnd, 1);
            UpdateWindow(hWnd);
            return true;

            //The explicit message pump is not necessary, messages are obviously dispatched by the framework.
            //However, if the while loop is implemented, the functions are called... Windows mysteries...
            //MSG msg;
            //while (GetMessage(out msg, IntPtr.Zero, 0, 0) != 0)
            //{
            //    TranslateMessage(ref msg);
            //    DispatchMessage(ref msg);
            //}
        }

        private static IntPtr myWndProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam)
        {
            switch (msg)
            {
                // All GUI painting must be done here
                case WM_PAINT:
                    break;

                case WM_LBUTTONDBLCLK :
                    MessageBox.Show("Doubleclick");
                    break;

                case WM_DESTROY:
                    DestroyWindow(hWnd);

                    //If you want to shutdown the application, call the next function instead of DestroyWindow
                    //PostQuitMessage(0);
                    break;

                default:
                    break;
            }
            return DefWindowProc(hWnd, msg, wParam, lParam);
        }
    }
}

Answer 2

问题是将字符串编组到LPStr，如果你这样做，那么类名就会起作用：

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    struct WNDCLASSEX
    {
        [MarshalAs(UnmanagedType.U4)]
        public int cbSize;
        [MarshalAs(UnmanagedType.U4)]
        public int style;
        public IntPtr lpfnWndProc;
        public int cbClsExtra;
        public int cbWndExtra;
        public IntPtr hInstance;
        public IntPtr hIcon;
        public IntPtr hCursor;
        public IntPtr hbrBackground;
        [MarshalAs(UnmanagedType.LPStr)]
        public string lpszMenuName;
        [MarshalAs(UnmanagedType.LPStr)]
        public string lpszClassName;
        public IntPtr hIconSm;
    }

    [DllImport("user32.dll", SetLastError = true, EntryPoint = "CreateWindowEx")]
    public static extern IntPtr CreateWindowEx(
       int dwExStyle,
       //UInt16 regResult,
       [MarshalAs(UnmanagedType.LPStr)]
       string lpClassName,
       [MarshalAs(UnmanagedType.LPStr)]
       string lpWindowName,
       UInt32 dwStyle,
       int x,
       int y,
       int nWidth,
       int nHeight,
       IntPtr hWndParent,
       IntPtr hMenu,
       IntPtr hInstance,
       IntPtr lpParam);