Question

我有2个表单，在Form1中，有很多事务需要完成，所以我使用了BackgroundWorker。所以在采取行动期间，我希望打开form2并显示进度条（动作的进度），所以我这样做了：

这是Form1

public partial class Form1 : Form
{
    Form2 form2 = new Form2();
    public Form1()
    {
        InitializeComponent();
        Shown += new EventHandler(Form1_Shown);

        // To report progress from the background worker we need to set this property
        backgroundWorker1.WorkerReportsProgress = true;
        // This event will be raised on the worker thread when the worker starts
        backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
        // This event will be raised when we call ReportProgress
        backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
    }

    void Form1_Shown(object sender, EventArgs e)
    {
        form2.Show();
        // Start the background worker
        backgroundWorker1.RunWorkerAsync();

    }


    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        // Your background task goes here
        for (int i = 0; i <= 100; i++)
        {
            // Report progress to 'UI' thread
            backgroundWorker1.ReportProgress(i);
            // Simulate long task
            System.Threading.Thread.Sleep(100);
        }
        form2.Close();
    }


    private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        // The progress percentage is a property of e
        form2.progressBar1.Value = e.ProgressPercentage;
    }
}

我在form2中有一个Progressbar，它的修饰符是公共的。问题是，当动作被合并时，form2（其中包含进度条）应该被关闭，所以我用了

    form2.Close();

但我收到此错误消息

  Cross-thread operation not valid: Control 'Form2' accessed from a thread other than the thread it was created on

我该如何解决这个问题？

Answer 1

使用委托使其线程安全

 if(form2.InvokeRequired)
    {
        form2.Invoke(new MethodInvoker(delegate { form2.Close() }));
    }

Answer 2

问题是控件只能由创建它的线程访问。

检查一下：

http://msdn.microsoft.com/en-us/library/ms171728.aspx

而且：

Cross-thread operation not valid: Control 'Form2' accessed from a thread other than the thread it was created on

跨线程操作无效：控制从其创建的线程以外的线程访问的“Form2”

2 个答案: