如何从backgrowndworker线程提供UI [英] how do I feed UI from backgrowndworker thread

问题描述

我使用以下代码更新进度条<   pre     lang   =  c＃ >  private void btnSearch_Click（object sender，EventArgs e）
 {
 
 
 worker.DoWork + = worker_DoWork; 
 worker.WorkerReportsProgress = true; 
 worker.ProgressChanged + = worker_ProgressChanged; 
 worker.RunWorkerAsync（）; 
 
} 
 
 void worker_ProgressChanged（object sender，ProgressChangedEventArgs e）
 {
 updateUI（）; 
} 
 
 
 void worker_DoWork（对象发送者，DoWorkEventArgs e）
 {
 
 myfunction（）; 
 Thread.Sleep（100）; 
 worker.ReportProgress（paths.currentProgress）; 
 
 
} 
 
 
 public void updateUI（）{
 pBar.Minimum = 0; 
 pBar.Maximum = 100; 
 pBar.Step = paths.currentProgress; //我从myfunction获得的值（）
 pBar.PerformStep（）; 
} <   / pre  > 它不会更新UI（进度条）。 
 
然后我用这种方式尝试
 
 <   pre     lang   =  c＃ >  private void btnSearch_Click（object sender，EventArgs e）
 {
 
 
 worker.DoWork + = worker_DoWork; 
 worker.RunWorkerAsync（）; 
 
} 
 
 
 void worker_DoWork（对象发送者，DoWorkEventArgs e）
 {
 
 myfunction（）; 
 Thread.Sleep（100）; 
 updateUI（）; 
 
 
 
} 
 
 
 public void updateUI（）{
 pBar.Minimum = 0; 
 pBar.Maximum = 100; 
 pBar.Step = paths.currentProgress; //我从myfunction获得的值（）
 pBar.PerformStep（）; 
} <   / pre  >  
 
这次它给了我错误
 <   pre  >  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：控制从创建它的线程以外的线程访问的'pBar'。<   / pre  >  
 
请帮助我如何从我调用的函数中提供UI在后台工作者。

解决方案

错误是因为您正在访问/修改在另一个线程上运行的UI控件。 />


//添加此行i你的构造函数

Control.CheckForIllegalCrossThreadCalls = false;



但请记住这是不是线程安全的。有关详细信息，请参阅此链接



感谢

I am using following code to update the progress bar <pre lang="c#"> private void btnSearch_Click(object sender, EventArgs e)
        {


            worker.DoWork += worker_DoWork;
            worker.WorkerReportsProgress = true;
            worker.ProgressChanged += worker_ProgressChanged;
            worker.RunWorkerAsync();

        }

        void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            updateUI();
        }


        void worker_DoWork(object sender, DoWorkEventArgs e)
        {

           myfunction();
            Thread.Sleep(100);
            worker.ReportProgress(paths.currentProgress);


        }


        public void updateUI(){
            pBar.Minimum = 0;
            pBar.Maximum = 100;
            pBar.Step = paths.currentProgress; // a value I get from myfunction()
            pBar.PerformStep();
        }</pre>  it do not update the UI(progressbar).

then I tried it this way

<pre lang="c#">private void btnSearch_Click(object sender, EventArgs e)
        {


            worker.DoWork += worker_DoWork;
            worker.RunWorkerAsync();

        }


        void worker_DoWork(object sender, DoWorkEventArgs e)
        {

           myfunction();
            Thread.Sleep(100);
           updateUI();



        }


        public void updateUI(){
            pBar.Minimum = 0;
            pBar.Maximum = 100;
            pBar.Step = paths.currentProgress; // a value I get from myfunction()
            pBar.PerformStep();
        }</pre>

this time it gives me the error
<pre>An exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll but was not handled in user code

Additional information: Cross-thread operation not valid: Control 'pBar' accessed from a thread other than the thread it was created on.</pre>

please help me how do I feed the UI from the function I have called in back ground worker.

解决方案

The error is because you are accessing /modifying the UI control which is running on another thread .

//add this line in your constructor
Control.CheckForIllegalCrossThreadCalls = false;

but remember this is not thread safe . for more details follow this Link

thanks

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