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我想在我的应用程序中将“关于”菜单添加到标题栏的上下文菜单中。

我在互联网上进行了多次搜索，发现了这个很棒的主题如何自定义 Windows 窗体的系统菜单？但是没有针对视觉 C++ 的解决方案。我试图从提到的主题中调整解决方案，但出现了问题。我可以看到上下文菜单中出现了一些新内容，但没有“关于”项。

这是我的代码：

#pragma once
#include <string>

namespace context_menu {

    using namespace System;
    using namespace System::ComponentModel;
    using namespace System::Collections;
    using namespace System::Windows::Forms;
    using namespace System::Data;
    using namespace System::Drawing;
    using namespace System::Runtime::InteropServices;
    using std::string;

    // P/Invoke constants
    const int WM_SYSCOMMAND = 0x112;
    const int MF_STRING = 0x0;
    const int MF_SEPARATOR = 0x800;

    // P/Invoke declarations
    [DllImport("user32.dll", CharSet = System::Runtime::InteropServices::CharSet::Auto, SetLastError = true)]
    extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert);

    [DllImport("user32.dll", CharSet = System::Runtime::InteropServices::CharSet::Auto, SetLastError = true)]
    extern bool AppendMenu(IntPtr hMenu, int uFlags, int uIDNewItem, string lpNewItem);

    [DllImport("user32.dll", CharSet = System::Runtime::InteropServices::CharSet::Auto, SetLastError = true)]
    extern bool InsertMenu(IntPtr hMenu, int uPosition, int uFlags, int uIDNewItem, string lpNewItem);


    /// <summary>
    /// Summary for Form1
    ///
    /// WARNING: If you change the name of this class, you will need to change the
    ///          'Resource File Name' property for the managed resource compiler tool
    ///          associated with all .resx files this class depends on.  Otherwise,
    ///          the designers will not be able to interact properly with localized
    ///          resources associated with this form.
    /// </summary>
    public ref class Form1 : public System::Windows::Forms::Form
    {
    // ID for the About item on the system menu
    private: static int SYSMENU_ABOUT_ID = 0x1;
    public:
        Form1(void)
        {
            InitializeComponent();
            //
            //TODO: Add the constructor code here
            //
        }

    protected:
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        ~Form1()
        {
            if (components)
            {
                delete components;
            }
        }

    private:
        /// <summary>
        /// Required designer variable.
        /// </summary>
        System::ComponentModel::Container ^components;

#pragma region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        void InitializeComponent(void)
        {
            this->SuspendLayout();
            // 
            // Form1
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(284, 261);
            this->Name = L"Form1";
            this->Text = L"Form1";
            this->ResumeLayout(false);
        }
#pragma endregion

    protected: virtual System::Void OnHandleCreated( System::EventArgs^ e ) override {
                System::Windows::Forms::Form::OnHandleCreated( e );
                // Get a handle to a copy of this form's system (window) menu
                IntPtr sysMenuHandle = GetSystemMenu( this->Handle, false );
                // Add a separator
                AppendMenu( sysMenuHandle, MF_SEPARATOR, 0, "" );
                // Add the About menu item
                AppendMenu( sysMenuHandle, MF_STRING, SYSMENU_ABOUT_ID, "&About…\n" );
            }

    protected: virtual System::Void WndProc( Message % m ) override {
                System::Windows::Forms::Form::WndProc( m );
                // Show test message
                if( ( m.Msg == WM_SYSCOMMAND ) && ( (int)m.WParam == SYSMENU_ABOUT_ID ) )
                {
                    MessageBox::Show( "Custom About Dialog" );
                }
            }
    };
}

这是我的 结果。

编辑

根据@David Yaw 的回答，我添加#include <Windows.h>并删除了所有不必要的代码。我需要解决一些小问题，过了一会儿它编译了。但随后出现了链接器错误：

1>context_menu.obj : error LNK2028: unresolved token (0A00001A) "extern "C" int __stdcall AppendMenuW(struct HMENU__ *,unsigned int,unsigned int,wchar_t const *)" (?AppendMenuW@@$$J216YGHPAUHMENU__@@IIPB_W@Z) referenced in function "protected: virtual void __clrcall context_menu::Form1::OnHandleCreated(class System::EventArgs ^)" (?OnHandleCreated@Form1@context_menu@@$$FM$AAMXP$AAVEventArgs@System@@@Z)
1>context_menu.obj : error LNK2028: unresolved token (0A00001B) "extern "C" struct HMENU__ * __stdcall GetSystemMenu(struct HWND__ *,int)" (?GetSystemMenu@@$$J18YGPAUHMENU__@@PAUHWND__@@H@Z) referenced in function "protected: virtual void __clrcall context_menu::Form1::OnHandleCreated(class System::EventArgs ^)" (?OnHandleCreated@Form1@context_menu@@$$FM$AAMXP$AAVEventArgs@System@@@Z)
1>context_menu.obj : error LNK2019: unresolved external symbol "extern "C" int __stdcall AppendMenuW(struct HMENU__ *,unsigned int,unsigned int,wchar_t const *)" (?AppendMenuW@@$$J216YGHPAUHMENU__@@IIPB_W@Z) referenced in function "protected: virtual void __clrcall context_menu::Form1::OnHandleCreated(class System::EventArgs ^)" (?OnHandleCreated@Form1@context_menu@@$$FM$AAMXP$AAVEventArgs@System@@@Z)
1>context_menu.obj : error LNK2019: unresolved external symbol "extern "C" struct HMENU__ * __stdcall GetSystemMenu(struct HWND__ *,int)" (?GetSystemMenu@@$$J18YGPAUHMENU__@@PAUHWND__@@H@Z) referenced in function "protected: virtual void __clrcall context_menu::Form1::OnHandleCreated(class System::EventArgs ^)" (?OnHandleCreated@Form1@context_menu@@$$FM$AAMXP$AAVEventArgs@System@@@Z)

所以现在怎么办？

代码：

#pragma once
#include <Windows.h>
#include <string>

namespace context_menu {

    using namespace System;
    using namespace System::ComponentModel;
    using namespace System::Collections;
    using namespace System::Windows::Forms;
    using namespace System::Data;
    using namespace System::Drawing;
    using namespace System::Runtime::InteropServices;
    using std::string;

    /// <summary>
    /// Summary for Form1
    ///
    /// WARNING: If you change the name of this class, you will need to change the
    ///          'Resource File Name' property for the managed resource compiler tool
    ///          associated with all .resx files this class depends on.  Otherwise,
    ///          the designers will not be able to interact properly with localized
    ///          resources associated with this form.
    /// </summary>
    public ref class Form1 : public System::Windows::Forms::Form
    {
    // ID for the About item on the system menu
    private: static int SYSMENU_ABOUT_ID = 0x1;


    public:
        Form1(void)
        {
            InitializeComponent();
            //
            //TODO: Add the constructor code here
            //
        }

    protected:
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        ~Form1()
        {
            if (components)
            {
                delete components;
            }
        }

    private:
        /// <summary>
        /// Required designer variable.
        /// </summary>
        System::ComponentModel::Container ^components;

#pragma region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        void InitializeComponent(void)
        {
            this->SuspendLayout();
            // 
            // Form1
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(284, 261);
            this->Name = L"Form1";
            this->Text = L"Form1";
            this->ResumeLayout(false);

        }
#pragma endregion

    protected: virtual System::Void OnHandleCreated( System::EventArgs^ e ) override {
                // Basic function call
                System::Windows::Forms::Form::OnHandleCreated( e );
                // Pointer to this
                HWND hWnd = static_cast<HWND>( this->Handle.ToPointer() );
                // Get a handle to a copy of this form's system (window) menu
                HMENU sysMenuHandle = GetSystemMenu( hWnd, false );
                // Add a separator
                AppendMenu( sysMenuHandle, MF_SEPARATOR, 0, L"" );
                // Add the About menu item
                AppendMenu( sysMenuHandle, MF_STRING, SYSMENU_ABOUT_ID, L"&About…\n" );
            }

    protected: virtual System::Void WndProc( Message % m ) override {
                // Basic function call
                System::Windows::Forms::Form::WndProc( m );
                // komunikat
                if( ( m.Msg == WM_SYSCOMMAND ) && ( (int)m.WParam == SYSMENU_ABOUT_ID ) )
                {
                    MessageBox::Show( "Custom About Dialog" );
                }
            }
    };
}
4

1 回答 1

0

您已经使用 C++，不需要 P/Invoke。直接#include <Windows.h>调用函数即可。

[DllImport("user32.dll", CharSet = System::Runtime::InteropServices::CharSet::Auto, SetLastError = true)]
extern bool AppendMenu(IntPtr hMenu, int uFlags, int uIDNewItem, string lpNewItem);
                                                                 ^^^^^^

string是 C# 中与 C++/CLI 中不同的类。由于出现了一些东西，但它不正确，我认为字符串很可能没有正确传递。

如果您切换到直接调用 C 函数，则字符串参数的类型检查将帮助您正确传递该参数。

综上所述，标准警告：当然可以用 C++/CLI 编写应用程序的主体，甚至可以使用 WinForms 用 C++/CLI 编写 GUI，但不建议这样做。C++/CLI 旨在用于互操作场景：在 C# 或其他 .Net 代码需要与非托管 C++ 接口的情况下，C++/CLI 可以提供两者之间的转换。因此，C++/CLI 具有 C++ 的所有复杂性、C# 的所有复杂性，以及它自己的一些复杂性。对于初级开发，如果您想要托管代码，建议使用带有 WinForms 或 WPF 的 C#，或者如果您想要非托管代码，则建议使用带有 MFC 的 C++。

于 2019-04-15T19:44:48.040 回答