将 2 个不同文本框中的 2 个文本文件从小写转换为大写

Question

我正在尝试将两个不同的 .txt 文件从小写转换为大写，主要 objective 是为了测量和显示执行时间。

如果文件以大写字母保存在我预定义的路径中并且程序显示执行时间，一切都会顺利。但是，在我的 GUI 中，文本不会转换，因为文本框中出现以下异常：

System.InvalidOperationException: Cross-thread operation not valid: Control "textBox2" accessed from a thread other than the thread it was created on.

namespace Threads
{
    public partial class Form1 : Form
    {   String prim= @"C:\Users\Wheelz\Desktop\Laborator09\fis1.txt";
        String secund= @"C:\Users\Wheelz\Desktop\Laborator09\fis2.txt";
        public Form1()'
        {
            InitializeComponent();
        }
    private void button1_Click(object sender, EventArgs e)
    {
        var read = File.ReadAllText(prim);
        textBox1.Text = read;

    }

    private void button2_Click(object sender, EventArgs e)
    {
        var read = File.ReadAllText(secund);
        textBox2.Text = read;

    }
    private void modifica1()
    {
        var read = File.ReadAllText(prim);
        read = read.ToUpper();
        File.WriteAllText(@"C:\Users\Wheelz\Desktop\Laborator09\fis1upper.txt", read);
        textBox1.Text = textBox1.Text.ToUpper();

    }
    private void modifica2()
    {

        var read = File.ReadAllText(prim);
        read = read.ToUpper();
        File.WriteAllText(@"C:\Users\Wheelz\Desktop\Laborator09\fis2upper.txt", read);
        textBox2.Text = textBox2.Text.ToUpper() ;


    }

    private void timp_Click(object sender, EventArgs e)
    {
        Thread firstThread = new Thread(new ThreadStart(modifica1));
        Thread secondThread = new Thread(new ThreadStart(modifica2));
        var ceas= new Stopwatch();
        ceas.Start();
        firstThread.Start();
        secondThread.Start();
        ceas.Stop();

        if (ceas.ElapsedMilliseconds == 1)
        {
            cron.Text = ceas.ElapsedMilliseconds.ToString() + "  milisecundă";
        }
        else
        {
            if ((ceas.ElapsedMilliseconds < 20))

                cron.Text = ceas.ElapsedMilliseconds.ToString() + "   milisecunde";

            else
                cron.Text = ceas.ElapsedMilliseconds.ToString() + "  de milisecunde";
        }



    }
}

}

Answer 1

使用 "BeginInvoke" 更新线程中的控制值。喜欢...

 private void modifica1()
    {
        var read = File.ReadAllText(prim);
        read = read.ToUpper();
        File.WriteAllText(@"C:\Users\Wheelz\Desktop\Laborator09\fis1upper.txt", read);
this.BeginInvoke(new MethodInvoker(() =>
{ 
textBox1.Text = textBox1.Text.ToUpper();
}));
    }
    private void modifica2()
    {

        var read = File.ReadAllText(prim);
        read = read.ToUpper();
        File.WriteAllText(@"C:\Users\Wheelz\Desktop\Laborator09\fis2upper.txt", read);
        this.BeginInvoke(new MethodInvoker(() =>
{ 
textBox2.Text = textBox2.Text.ToUpper();
}));
    }

Answer 2

是的，不能将主线程中调用的表单共享到子线程中。

您必须使用 Delegate to mainthread 来更新文本框。

阅读： Invoke(Delegate)

Controls in Windows Forms are bound to a specific thread and are not thread safe. Therefore, if you are calling a control's method from a different thread, you must use one of the control's invoke methods to marshal the call to the proper thread. This property can be used to determine if you must call an invoke method, which can be useful if you do not know what thread owns a control.

您还可以使用 backgroundworker or async

将 2 个不同文本框中的 2 个文本文件从小写转换为大写

Converting 2 txt files in 2 different texboxes from lowercase to uppercase

c#

multithreading

textbox

visual-studio