c# - for 循环中的动态标签文本

Question

我用 C# 做了一个简单的 WF，试图动态改变标签。

但是，当我运行这段代码时，没有任何可见的变化，直到代码运行之后，它才变为“Processing 9”，0-8 从未显示。是因为在循环内吗？

 private void button1_Click(object sender, EventArgs e)
    {
        for (int i = 0; i < 10; i++)
        {
            label9.Text = "Processing " + i.ToString();
            Thread.Sleep(1000);
        }
    }

编辑:X-Tech 的代码有效，但当我尝试将其合并到我的代码中时，出现以下线程问题。我正在尝试在进度条摇摆时动态更改循环中的 label.text:

System.Windows.Forms.dll 中出现“System.InvalidOperationException”类型的异常，但未在用户代码中处理附加信息:跨线程操作无效:从创建它的线程以外的线程访问控件“progressBar1”。如果有这个异常的处理程序，程序可以安全地继续

我不确定如何解决这个问题，因为我对 Task.Factory.StartNew() 和 Invoke 语句不是很熟悉。

编辑 2:改编代码:

 Task.Factory.StartNew(() =>
 {
      for (int i = 0; i < lstFilesToZip.Items.Count; i++)
      {
          zipArray[i] = lstFilesToZip.Items[i].ToString();
          // Report progress.
          ExecuteSecure(() => label9.Text = "Processing :" + Path.GetFileNameWithoutExtension(lstFilesToZip.Items[i].ToString()));
          ExecuteSecure(() => progressBar1.PerformStep());

          string zipFileName = Path.GetFileName(zipArray[i]);
          string newFolder = txtDestinationFolder.Text + "\\" + Path.GetFileNameWithoutExtension(zipArray[i]);
          //check to see if a directory with the file name for the zip file already exists, if not, it will create it
          if (Directory.Exists(newFolder) == false)
          {
                DirectoryInfo newPath = Directory.CreateDirectory(newFolder);
                if (lstCommonFiles.Items.Count > 0)
                {
                     //copies each file in the common file list to each new folder created, the boolean indicates that it will overwrite existing files (true) or won't (false)
                     for (int k = 0; k < lstCommonFiles.Items.Count; k++)
                     {
                          File.Copy(lstCommonFiles.Items[k].ToString(), (newFolder + "\\" + Path.GetFileName(commonArray[k])), true);
                     }
                }
                //adds the zip file into the folder as well
                File.Copy(zipArray[i], (newFolder + "\\" + zipFileName), true);

          }
    }

    if (txtCommonFiles.Text.Length <= 0)
    {
          string result = "There are no common files selected, would you still like to proceed?";
          DialogResult result1 = MessageBox.Show(result, "Common Files Missing", MessageBoxButtons.YesNo);
          if (result1 == DialogResult.No)
          {
               return;
          }
    }
    string[] dirs = Directory.GetDirectories(txtDestinationFolder.Text);

    // Grabs the folders in the newly created directory
    foreach (string dir in dirs)
          lstDestinationFinal.Items.Add(dir);

    //send sample file contents to preview window
    string[] sampleFiles = Directory.GetFiles(lstDestinationFinal.Items[0].ToString());

    //grabs the files
    foreach (string zipFiles in sampleFiles)
         lstSampleFile.Items.Add(zipFiles);

    ExecuteSecure(() =>tabControl1.SelectedTab = tabPage2);
});

以及添加的方法:

 private void ExecuteSecure(Action action)
    {
        if (InvokeRequired)
        {
            Invoke(new MethodInvoker(() => action()));
        }
        else
        {
            action();
        }
    }

Answer 1

试试这个

Task.Factory.StartNew(() =>
{
     for (int i = 0; i < 10; i++)
     {              
          Invoke(new MethodInvoker(() => label9.Text = "Processing " + i.ToString()));
          Thread.Sleep(1000);
     }
});

编辑:

Task.Factory.StartNew(() =>
{
     for (int i = 0; i < 10; i++)
     {
          // Any GUI control which you want to use within thread,
          // you need Invoke using GUI thread. I have declare a method below for this
          //Now use this method as
          ExecuteSecure(() => label9.Text = "Processing " + i);
          ExecuteSecure(() => progressBar1.Value = i * 10);
          //... other code etc.
          Thread.Sleep(1000);
     }
});


//---
private void ExecuteSecure(Action action)
{
    if (InvokeRequired)
    {
        Invoke(new MethodInvoker(() => action()));
    }
    else
    {
        action();
    }
}