我正在尝试关注如何在Windows窗体中创建线程的this example。纯粹按照这个例子，我在构建时会遇到多个语法错误。
我正在使用/clr:oldSyntax编译器开关来编译示例。
Form1类的初始化是错误的第一个来源：
public ref class Form1 : public System::Windows::Forms::Form
{
错误：
1>d:\programming applications\vs2005\threadexample\threadexample\Form1.h(24) : error C2059: syntax error : 'public'
1>d:\programming applications\vs2005\threadexample\threadexample\Form1.h(24) : error C2059: syntax error : 'public'
1>d:\programming applications\vs2005\threadexample\threadexample\Form1.h(25) : error C2143: syntax error : missing ';' before '{'
1>d:\programming applications\vs2005\threadexample\threadexample\Form1.h(25) : error C2447: '{' : missing function header (old-style formal list?)
这些错误究竟来自哪里？
完整代码：
#pragma once
using namespace System::Threading;
namespace ThreadExample
{
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: System::Windows::Forms::ProgressBar^ progressBar1;
private:
/// <summary>
/// Required designer variable.
/// </summary>
System::ComponentModel::Container ^components;
private: Thread *trd;
#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->progressBar1 = (gcnew System::Windows::Forms::ProgressBar());
this->SuspendLayout();
//
// button1
//
this->button1->Location = System::Drawing::Point(197, 12);
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);
//
// progressBar1
//
this->progressBar1->Location = System::Drawing::Point(94, 162);
this->progressBar1->Name = L"progressBar1";
this->progressBar1->Size = System::Drawing::Size(100, 23);
this->progressBar1->TabIndex = 1;
this->progressBar1->Click += gcnew System::EventHandler(this, &Form1::progressBar1_Click);
//
// Form1
//
this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
this->ClientSize = System::Drawing::Size(284, 261);
this->Controls->Add(this->progressBar1);
this->Controls->Add(this->button1);
this->Name = L"Form1";
this->Text = L"Form1";
this->Load += gcnew System::EventHandler(this, &Form1::Form1_Load);
this->ResumeLayout(false);
}
#pragma endregion
private: System::Void Form1_Load(System::Object^ sender, System::EventArgs^ e)
{
ThreadStart *myThreadDelegate = new ThreadStart(this, repeat);
trd = new Thread(myThreadDelegate);
trd->IsBackground = true;
trd->Start();
}
private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e)
{
MessageBox::Show(S"This is the main thread");
}
private: System::Void progressBar1_Click(System::Object^ sender, System::EventArgs^ e)
{
}
};
__delegate void DelegateThreadTask();
private: void ThreadTask()
{
int stp;
int newval;
Random *rnd=new Random();
if (progressBar1->InvokeRequired == false)
{
stp=this->progressBar1->Step*rnd->Next(-1,2);
newval = this->progressBar1->Value + stp;
if (newval > this->progressBar1->Maximum)
newval = this->progressBar1->Maximum;
else if (newval < this->progressBar1->Minimum)
newval = this->progressBar1->Minimum;
this->progressBar1->Value = newval;
}
else
{
DelegateThreadTask *myThreadDelegate = new DelegateThreadTask(this,ThreadTask);
this->Invoke(myThreadDelegate);
}
}
private: void repeat()
{
while(true)
{
ThreadTask();
Thread::Sleep(100);
}
}
}
答案 0 :(得分：0)
C ++ / CLI的旧语法使用__gc来声明类。
参考文献：
测试1：
public ref class Foo
{
};
编译结果：
OldSyntax.cpp
OldSyntax.cpp(1): error C2059: syntax error : 'public'
OldSyntax.cpp(2): error C2143: syntax error : missing ';' before '{'
OldSyntax.cpp(2): error C2447: '{' : missing function header (old-style formal list?)
测试2：
public __gc class Foo
{
};
编译结果：没有错误。
（注意：我使用VS2012进行测试。我不再安装VS2005; 2005年的错误信息可能略有不同。）