从另一个线程写入文本框? [英] Writing to a TextBox from another thread?

问题描述

我不知道如何让 C# Windows 窗体应用程序从线程写入文本框.例如在 Program.cs 中，我们有绘制表单的标准 main():

I cannot figure out how to make a C# Windows Form application write to a textbox from a thread. For example in the Program.cs we have the standard main() that draws the form:

static void Main()
{
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    Application.Run(new Form1());
}

然后我们在 Form1.cs 中有:

Then we have in the Form1.cs:

public Form1()
{
    InitializeComponent();

    new Thread(SampleFunction).Start();
}

public static void SampleFunction()
{
    while(true)
        WindowsFormsApplication1.Form1.ActiveForm.Text += "hi. ";
}

我是不是完全错了?

更新

这是本德威提供的工作代码示例:

Here is the working code sample provided from bendewey:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        new Thread(SampleFunction).Start();
    }

    public void AppendTextBox(string value)
    {
        if (InvokeRequired)
        {
            this.Invoke(new Action<string>(AppendTextBox), new object[] {value});
            return;
        }
        textBox1.Text += value;
    }

    void SampleFunction()
    {
        // Gets executed on a seperate thread and 
        // doesn't block the UI while sleeping
        for(int i = 0; i<5; i++)
        {
            AppendTextBox("hi.  ");
            Thread.Sleep(1000);
        }
    }
}

推荐答案

在你的 MainForm 上创建一个函数来设置文本框，检查 InvokeRequired

On your MainForm make a function to set the textbox the checks the InvokeRequired

public void AppendTextBox(string value)
{
    if (InvokeRequired)
    {
        this.Invoke(new Action<string>(AppendTextBox), new object[] {value});
        return;
    }
    ActiveForm.Text += value;
}

虽然在你的静态方法中你不能只是调用.

although in your static method you can't just call.

WindowsFormsApplication1.Form1.AppendTextBox("hi. ");

你必须在某处有一个对 Form1 的静态引用，但这并不是真正推荐或必要的，你能不能让你的 SampleFunction 不是静态的，如果是这样你就可以调用

you have to have a static reference to the Form1 somewhere, but this isn't really recommended or necessary, can you just make your SampleFunction not static if so then you can just call

AppendTextBox("hi. ");

它将附加到不同的线程上，并在需要时使用 Invoke 调用编组到 UI.

It will append on a differnt thread and get marshalled to the UI using the Invoke call if required.

完整示例

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        new Thread(SampleFunction).Start();
    }

    public void AppendTextBox(string value)
    {
        if (InvokeRequired)
        {
            this.Invoke(new Action<string>(AppendTextBox), new object[] {value});
            return;
        }
        textBox1.Text += value;
    }

    void SampleFunction()
    {
        // Gets executed on a seperate thread and 
        // doesn't block the UI while sleeping
        for(int i = 0; i<5; i++)
        {
            AppendTextBox("hi.  ");
            Thread.Sleep(1000);
        }
    }
}

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