在c#中使用web浏览器和线程时，会出现InvalidCastException异常

本文关键字：异常 InvalidCastException 线程 浏览器 web | 更新日期: 2023-09-27 18:02:26

当我试图在backgroundWorker中使用webBrowser组件时。DoWork函数，我得到了这个异常:

系统。InvalidCastException未被用户代码处理

https://i.stack.imgur.com/EJFT3.jpg

这是我的代码:

void m_oWorker_DoWork(object sender, DoWorkEventArgs e)
    {
        //NOTE : Never play with the UI thread here...
        string line;
        //time consuming operation
        while ((line=sr.ReadLine()) != null ){
            int index = line.IndexOf(":");
            HtmlDocument doc = web.Document;
            Thread.Sleep(1000);
            m_oWorker.ReportProgress(cnt);
            //If cancel button was pressed while the execution is in progress
            //Change the state from cancellation ---> cancel'ed
            if (m_oWorker.CancellationPending)
            {
                e.Cancel = true;
                m_oWorker.ReportProgress(0);
                return;
            }
            cnt++;
        }
        //Report 100% completion on operation completed
        m_oWorker.ReportProgress(100);
    }

还是c#中使用线程的另一种方式?

原因当我使用线程。睡眠方法在主界面冻结!!

在c#中使用web浏览器和线程时，会出现InvalidCastException异常

WebBrowser不喜欢被其他线程访问。试着像这样把它传递给RunWorkerAsync():

    private void button1_Click(object sender, EventArgs e)
    {
        HtmlDocument doc = web.Document;
        m_oWorker.RunWorkerAsync(doc);
    }
    void m_oWorker_DoWork(object sender, DoWorkEventArgs e)
    {
        HtmlDocument doc = (HtmlDocument)e.Argument;
        //NOTE : Never play with the UI thread here...
        string line;
        //time consuming operation
        while ((line = sr.ReadLine()) != null)
        {
            int index = line.IndexOf(":");
            Thread.Sleep(1000);
            m_oWorker.ReportProgress(cnt);
            //If cancel button was pressed while the execution is in progress
            //Change the state from cancellation ---> cancel'ed
            if (m_oWorker.CancellationPending)
            {
                e.Cancel = true;
                m_oWorker.ReportProgress(0);
                return;
            }
            cnt++;
        }
        //Report 100% completion on operation completed
        m_oWorker.ReportProgress(100);
    }
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