Question

我已经搜索了几天，并尝试了我能找到的所有解决方案。我知道这是我做得不好的事情，但是，我不确定正确的方法是什么。

我有一个ASP.Net C＃网站，在.Net Framework 4.5上运行。我在表单上有一个链接按钮，单击该按钮时会使用ThreadPool触发长时间运行的进程。我有一个委托回调设置，代码在取消进程或完成时触发。（我使用取消令牌取消流程，如果重要的话，流程是活动报告。）

就像我说的，一切都很好，除了当回调代码触发它不执行javascript时。（仅供参考 - 这不是一个javascript回调，只是尝试在进程完成时触发一些javascript代码。）

这是我开始报告的代码......

string sThreadID = Thread.CurrentThread.ManagedThreadId.ToString（）; ThreadPool.QueueUserWorkItem（new WaitCallback（StartReport），cts.Token）;

以下是StartReport的代码....

public static void StartReport(object obj) {
    try {
        OnTaskCompleteDelegate callback = new OnTaskCompleteDelegate(OnTaskComplete);
        BoyceReporting.CallReport(boyce.BoyceThreadingEnvironment.OBRO, "THREADING");
        if (boyce.BoyceThreadingEnvironment.CTS.Token.IsCancellationRequested) {
            boyce.BoyceThreadingEnvironment.SESSION.sScriptToExecute = "alert('Report Canceled By User');";
            callback("CANCELED");
        } else {
            callback("FINISHED");
        }
    } catch {
        throw;
    }
}

以下是CallBack代码的代码.....

public static void OnTaskComplete(string ReportResult) {
    try {
        sReportResult = ReportResult;
        if (ReportResult == "CANCELED") {
            //  In case we need to do additional things if the report is canceled
        }
        string sThreadID = Thread.CurrentThread.ManagedThreadId.ToString();
        boyce.BoyceThreadingEnvironment.THISPAGE.ClientScript.RegisterStartupScript(boyce.BoyceThreadingEnvironment.THISPAGE.GetType(), "FireTheScript" + DateTime.Now.ToString(), boyce.BoyceThreadingEnvironment.SESSION.sScriptToExecute, true);
        ScriptManager.RegisterStartupScript(boyce.BoyceThreadingEnvironment.THISPAGE, boyce.BoyceThreadingEnvironment.THISPAGE.GetType(), "DisplayReport" + DateTime.Now.ToString(), boyce.BoyceThreadingEnvironment.SESSION.sScriptToExecute, true);
    } catch {
        throw;
    }
}

这是我遇到的问题......

一切正常，但我无法获取最后一行代码来解雇脚本。 ScriptManager.RegisterStartupScript

这是我认为正在发生的事情......

从查看线程ID，我确定代码未触发的原因是因为我试图在Call Back事件中触发的ScriptManager代码位于不同于主线程的线程上。

这是我的问题.....

（1）我是否正确解释了为什么这不会触发JavaScript （2）我如何（从CallBack内部）获取此JavaScript？有没有办法强制它在主线程上执行？

Answer 1

它没有在JS中解雇，因为你正在关闭一个新线程。与此同时，请求早已返回到客户端并关闭连接。当线程试图向Response写出一些内容时，它已经完成了。

而不是这样做，只需按一下UpdatePanel按钮点击（或启动报告的任何内容）。然后，您不需要启动新线程。

Answer 2

Here is the cod I used in the C# Code Behind to call the web service to start monitoring this process.
----------------------------------------------------------------------------------------------

                CurrentSession.bIsReportRunning = true;
                ScriptManager.RegisterStartupScript(this, this.GetType(), "WaitForReport" + DateTime.Now.ToString(), "jsWaitOnCallReport();", true);
                MultiThreadReport.RunTheReport(HttpContext.Current, CurrentSession, this, oBRO);

Here is the code that calls the method, using the threadpool, and the method called..
----------------------------------------------------------------------------------------------
            ThreadPool.QueueUserWorkItem(new WaitCallback(StartReport), cts.Token);

    public static void StartReport(object obj) {
        try {
            OnTaskCompleteDelegate callback = new OnTaskCompleteDelegate(OnTaskComplete);
            BoyceReporting.CallReport(boyce.BoyceThreadingEnvironment.OBRO, "THREADING");
            HttpContext.Current = boyce.BoyceThreadingEnvironment.CONTEXT;
            if (boyce.BoyceThreadingEnvironment.CTS.Token.IsCancellationRequested) {
                boyce.BoyceThreadingEnvironment.SESSION.sScriptToExecute = "alert('Report Canceled By User');";
                boyce.BoyceThreadingEnvironment.SESSION.bIsReportRunning = false;
                callback("CANCELED");
            } else {
                boyce.BoyceThreadingEnvironment.SESSION.bIsReportRunning = false;
                callback("FINISHED");
            }
        } catch {
            throw;
        }
    }

Here is the web service method I created to monitor the process, with a built in safety net
--------------------------------------------------------------------------------------------

    [WebMethod(EnableSession = true)]
    public string WaitOnReport() {
        try {
            HttpContext.Current = boyce.BoyceThreadingEnvironment.CONTEXT;
            SessionManager CurrentSession;
            CurrentSession = (SessionManager)boyce.BoyceThreadingEnvironment.SESSION;

            DateTime dtStartTime = DateTime.Now;
            DateTime dtCurrentTime = DateTime.Now;
            if (CurrentSession != null) {
                do {
                    //  Build a safety limit into this loop to avoid an infinate loope
                    //  If this runs longer than 20 minutes, then force an error due to timeout
                    //  This timeout should be lowered when they find out what the issue is with 
                    //  the "long running reports".  For now, I set it to 20 minutes but shoud be MUCH lower.
                    dtCurrentTime = DateTime.Now;
                    TimeSpan span = dtCurrentTime-dtStartTime;
                    double totalMinutes = span.TotalMinutes;
                    if (totalMinutes>=20) {
                        return "alert('Error In Creating Report (Time-Out)');";
                    }
                } while (CurrentSession.bIsReportRunning == true);
                //  If all goes well, return the script to either OPEN the report or display CANCEL message
                return CurrentSession.sScriptToExecute;
            } else {
                return "alert('Error In Creating Report (Session)');";
            }
        } catch {
            throw;
        }
    }


And here is the JavaScript code I used to initiate the Web Service Call and Also The Postback
--------------------------------------------------------------------------------------------
function jsWaitOnCallReport() {
    try {
        var oWebService = BoyceWebService.WaitOnReport(jsWaitOnCallReport_CallBack);
    } catch (e) {
        alert('Error In Calling Report Screen -- ' + e);
    }
}
function jsWaitOnCallReport_CallBack(result) {
    try {
        eval(result); 
        var myExtender = $find('ModalPopupExtenderPROGRESS');
        if (myExtender != null) {
            try {
                myExtender.hide();
            } catch (e) {
                //  Ignore Any Error That May Be Thrown Here
            }
        }
        $find('PROGRESS').hide();
    } catch (e) {
        alert('Error In Opening Report Screen -- ' + e);
    }
}

Hope this helps someone else out..  Like I said, I am not sure this is the best solution, but it works..   I would be interested in other solutions for this issue to try...  Thanks.

ASP.Net ThreadPool委托回调 - JavaScript不在回调线程上触发