c++ - 使用 Visual C++ 2010 在两个窗体之间传递数据

Question

所以，我有一个简单的表单应用程序：我有一个表单 1 ( Form1.h ) 和第二个表单 ( Form2.h )。Form1 由一个简单的Add User 按钮组成（在这个阶段，它什么都不做，只是打开 form2 并隐藏 form1）。（到此为止，一切正常）。
但是，当我向应该再次打开 form1的 Form2 添加一个“完成”按钮时，出现以下错误：左侧 -> 显示必须指向类/结构/联合/通用类型 f1：未声明的标识符 Form1：未声明的标识符请帮助！

代码是：

//Project Name: MultipleForms
//Form1.h
#ifndef FORM1_H
#define FORM1_H
#pragma once
#include "Form2.h"
namespace MultipleForms {

    using namespace System;
    using namespace System::ComponentModel;
    using namespace System::Collections;
    using namespace System::Windows::Forms;
    using namespace System::Data;
    using namespace System::Drawing;

    /// <summary>
    /// Summary for Form1
    /// </summary>
    public ref class Form1 : public System::Windows::Forms::Form
    {
    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: System::Windows::Forms::Button^  btnAddUser;
    private: System::Windows::Forms::Button^  btnExit;
    protected: 

    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->btnAddUser = (gcnew System::Windows::Forms::Button());
            this->btnExit = (gcnew System::Windows::Forms::Button());
            this->SuspendLayout();
            // 
            // btnAddUser
            // 
            this->btnAddUser->Location = System::Drawing::Point(78, 44);
            this->btnAddUser->Name = L"btnAddUser";
            this->btnAddUser->Size = System::Drawing::Size(75, 23);
            this->btnAddUser->TabIndex = 0;
            this->btnAddUser->Text = L"Add User";
            this->btnAddUser->UseVisualStyleBackColor = true;
            this->btnAddUser->Click += gcnew System::EventHandler(this, &Form1::btnAddUser_Click);
            // 
            // btnExit
            // 
            this->btnExit->Location = System::Drawing::Point(263, 136);
            this->btnExit->Name = L"btnExit";
            this->btnExit->Size = System::Drawing::Size(75, 23);
            this->btnExit->TabIndex = 1;
            this->btnExit->Text = L"Exit";
            this->btnExit->UseVisualStyleBackColor = true;
            this->btnExit->Click += gcnew System::EventHandler(this, &Form1::btnExit_Click);
            // 
            // Form1
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(410, 200);
            this->Controls->Add(this->btnExit);
            this->Controls->Add(this->btnAddUser);
            this->Name = L"Form1";
            this->Text = L"Form1";
            this->ResumeLayout(false);

        }
#pragma endregion
    private: System::Void btnAddUser_Click(System::Object^  sender, System::EventArgs^  e) {
                 Form2^ f2 = gcnew Form2();
                 f2->Show();
                 this->Hide();
             }
    private: System::Void btnExit_Click(System::Object^  sender, System::EventArgs^  e) {
                 exit(1);
             }
    };
}

#endif

//Form2.h

#ifndef FORM2_H
#define FORM2_H
#pragma once
#include "Form1.h"

#include<stdlib.h>

namespace MultipleForms {

    using namespace System;
    using namespace System::ComponentModel;
    using namespace System::Collections;
    using namespace System::Windows::Forms;
    using namespace System::Data;
    using namespace System::Drawing;

    /// <summary>
    /// Summary for Form2
    /// </summary>
    public ref class Form2 : public System::Windows::Forms::Form
    {
    public:
        Form2(void)
        {
            InitializeComponent();
            //
            //TODO: Add the constructor code here
            //
        }

    protected:
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        ~Form2()
        {
            if (components)
            {
                delete components;
            }
        }
    private: System::Windows::Forms::Button^  btnDone;
    protected: 

    protected: 

    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->btnDone = (gcnew System::Windows::Forms::Button());
            this->SuspendLayout();
            // 
            // btnDone
            // 
            this->btnDone->Location = System::Drawing::Point(98, 110);
            this->btnDone->Name = L"btnDone";
            this->btnDone->Size = System::Drawing::Size(75, 23);
            this->btnDone->TabIndex = 0;
            this->btnDone->Text = L"Done";
            this->btnDone->UseVisualStyleBackColor = true;
            this->btnDone->Click += gcnew System::EventHandler(this, &Form2::btnDone_Click);
            // 
            // Form2
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(292, 273);
            this->Controls->Add(this->btnDone);
            this->Name = L"Form2";
            this->Text = L"Form2";
            this->ResumeLayout(false);

        }
#pragma endregion
    private: System::Void btnDone_Click(System::Object^  sender, System::EventArgs^  e) {
                 Form1^ f1 = gcnew Form1();
                 f1->Show();
                 this->Hide();
             }
    };
}
#endif

score 1 · Accepted Answer

问题是因为您将 Form1.h 相互包含到 Form2.h 中，反之亦然。因此，在 btnAddUser_Click 和 btnDone_Click 中的引用中需要它们之前，它们的类定义并不完全已知。解决方案是定义其中一项或两项（即，在独立的.cpp 文件中）。

score 0 · Accepted Answer

您不需要在表格2中添加“显示”代码。您只需在表格1中输入即可。因为当您单击 form1 中的该按钮时，会显示 form2 而隐藏 form1。下一行说它应该再次打开。所以当你关闭form2时，form1可以再次打开。

但我认为你和我有同样的问题，就是以两种形式进行交流，反之亦然。我想知道如何将一条消息发送到 form2，然后将一条消息从 form2 发送到 form1。我认为你有同样的问题。

c++ - 使用 Visual C++ 2010 在两个窗体之间传递数据

2 回答 2

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