ボタンがクリックされたときに長方形を作成する必要があります。与えられたコードを試しましたが、機能しません。ボタンがクリックされたときにtrueになるフラグ「mdraw」を作成しようとしました。form_paintに条件があり、「mdraw」がtrueになったときにのみ長方形が作成されます。しかし、ボタンをクリックした後は何も起こりません！
Windowsフォームアプリケーション（CLR）を使用しています。Microsoft Visual C++2008。
#pragma once
namespace try1 {
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
///
/// 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
{
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^ button1;
protected:
private:
/// <summary>
/// Required designer variable.
/// </summary>
System::ComponentModel::Container ^components;
private: System::Windows::Forms::Label^ label1;
public:
bool mdraw;
#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->button1 = (gcnew System::Windows::Forms::Button());
this->label1 = (gcnew System::Windows::Forms::Label());
this->SuspendLayout();
//
// button1
//
this->button1->Location = System::Drawing::Point(98, 35);
this->button1->Name = L"button1";
this->button1->Size = System::Drawing::Size(75, 23);
this->button1->TabIndex = 0;
this->button1->Text = L"button1";
this->button1->UseVisualStyleBackColor = true;
this->button1->Click += gcnew System::EventHandler(this, &Form1::button1_Click);
//
// label1
//
this->label1->AutoSize = true;
this->label1->Location = System::Drawing::Point(51, 77);
this->label1->Name = L"label1";
this->label1->Size = System::Drawing::Size(0, 13);
this->label1->TabIndex = 1;
//
// Form1
//
this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
this->ClientSize = System::Drawing::Size(284, 262);
this->Controls->Add(this->label1);
this->Controls->Add(this->button1);
this->Name = L"Form1";
this->Text = L"Form1";
this->Load += gcnew System::EventHandler(this, &Form1::Form1_Load);
this->Paint += gcnew System::Windows::Forms::PaintEventHandler(this, &Form1::Form1_Paint);
this->ResumeLayout(false);
this->PerformLayout();
}
#pragma endregion
private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e) {
mdraw=true;
label1->Text=button1->Text;
}
private: System::Void Form1_Paint(System::Object^ sender, System::Windows::Forms::PaintEventArgs^ e) {
Pen^ redPen = gcnew Pen(Color::Red);
int i,n;
i=20;
n=0;
if(mdraw)
{
while(n<=50)
{
e->Graphics->DrawRectangle(redPen,i,140,10,60);
i=i+20;
n+=1;
}
}
}
};
}