那些遇到过的问题

如何在asp.netweb应用程序中显示哪个是第一个的异步结果？

hmk*_*hmk 8 asp.net asynchronous

我必须在三个类文件中发送三个异步请求,3个请求响应时间不同,第一个是2秒,第二个是7秒,第三个是4秒,现在我必须在2秒内显示第一个响应,并在2秒后显示第三个响应,最后显示第二个响应,但现在我的结果所有响应显示在完成三个响应后,请给我任何建议,这是非常紧急,请.....

我的代码是 

public delegate string AsyncMethodCaller(string name);
        public delegate string AsyncMethodCallertest(string name);
        public delegate string NatilusAsyn(string name);
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按钮单击事件

     AsyncMethodCaller caller = new AsyncMethodCaller(ps.PennStarService);
        IAsyncResult result = caller.BeginInvoke(txtFirst.Text, null, null);
    NatilusAsyn caller123 = new NatilusAsyn(cs.PennStarService);
        IAsyncResult result123 = caller123 .BeginInvoke(txtthird.Text, null, null);
        AsyncMethodCallertest cltest = new AsyncMethodCallertest(ps.testHi);
        IAsyncResult tetsresult = cltest.BeginInvoke(txtSecond.Text, null, null);
        lblFirst.Text = caller.EndInvoke(result);           
        lblSecond.Text = cltest.EndInvoke(tetsresult);
     lblthird.Text = caller123.EndInvoke(result123);
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谢谢你,hemanth

Jup*_*aol 5

我认为问题的根源是了解ASP.Net请求会发生什么.

每个页面的生命周期都包含一系列事件,有关详细信息,请查看此答案.每个请求都由来自当前应用程序的AppDomain的工作线程处理.在页面管道完成之前,不会将响应发送给用户.

关于线程:

可以在中配置同时可用线程的数量machine.config.要理解的关键点是这些线程数是固定的,这意味着当达到最大并发线程数时,后续请求将被放入队列中,可以放入队列的请求数仅为受服务器内存的限制.

当一个工作线程调用一个很长时间的操作时,你阻塞该线程,直到操作完成,这意味着,如果有多个并发用户,可能会阻止所有可用线程,强制将新请求放入队列,在最坏的情况下,导致503错误 - 服务不可用.

防止这种情况的方法是在后台线程中调用这些方法.与您的代码类似,但行为不是您在这种情况下所期望的行为,您的代码正在等待线程结束以完成页面请求,这是您同时接收结果的原因(最后)请求).

有关异步执行asp.net页面的更多详细信息,请参阅这篇优秀文章

现在,为了获得您需要的结果:

(这是一个完整的工作示例,在此示例中,我使用Rx - Reactive Programming在新线程中运行耗时长的方法,如果您愿意,可以将其更改为使用其他框架,我更喜欢使用Rx,因为我觉得更适合API)

使用PageMethods

代码背后

    [WebMethod]
    public static string Execute1()
    {
        JavaScriptSerializer j = new JavaScriptSerializer();
        string r = string.Empty;
        var o = Observable.Start(() =>
            {
                Thread.Sleep(2000);
                r = "My Name1: " + DateTime.Now.ToString() + " Background thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
            }, Scheduler.NewThread);
        o.First();
        r += " Main thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        r = j.Serialize(new { res = r });
        return r;
    }

    [WebMethod]
    public static string Execute2()
    {
        JavaScriptSerializer j = new JavaScriptSerializer();
        string r = string.Empty;
        var o = Observable.Start(() =>
        {
            Thread.Sleep(7000);
            r = "My Name2: " + DateTime.Now.ToString() + " Background thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        }, Scheduler.NewThread);
        o.First();
        r += " Main thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        r = j.Serialize(new { res = r });
        return r;
    }

    [WebMethod]
    public static string Execute3()
    {
        JavaScriptSerializer j = new JavaScriptSerializer();
        string r = string.Empty;
        var o = Observable.Start(() =>
        {
            Thread.Sleep(4000);
            r = "My Name3: " + DateTime.Now.ToString() + " Background thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        }, Scheduler.NewThread);
        o.First();
        r += " Main thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        r = j.Serialize(new { res = r });
        return r;
    }
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ASPX

....
<script type="text/javascript" src="Scripts/jquery-1.7.2.min.js"></script>
....
<asp:ScriptManager runat="server" />
<input type="button" id="callAsync" name="callAsync" value="Call Async" />
<div id="first"></div>
<script type="text/javascript">
    function onsuccess1(msg) {
        var result = Sys.Serialization.JavaScriptSerializer.deserialize(msg.d);
        var h = $("#first").html();
        $("#first").html( h + "<br/>&nbsp;&nbsp;&nbsp;&nbsp;Result: " + result.res);
    }
    function onerror1(xhr) {
        alert(xhr.responseText);
    }
    function callMyMethod(url, mydata, onsuccess, onerror) {
        var h = $("#first").html();
        $("#first").html(h + "<br/>&nbsp;&nbsp;Calling Method: " + new Date());
        return $.ajax({
            cache: false,
            type: "POST",
            async: true,
            url: url,
            data: mydata, 
            contentType: "application/json",
            dataType: "json",
            success: function (msg) {
                onsuccess(msg);
            },
            error: function (xhr) {
                onerror(xhr);
            }
        });
    }
    $(document).ready(function () {
        $("#callAsync").click(function () {
            var h = $("#first").html();
            $("#first").html(h + "<br/>New call: " + new Date());
            callMyMethod("DynamicControls.aspx/Execute1", "{}", function (data) { onsuccess1(data); }, function (data) { onerror1(data); });
            callMyMethod("DynamicControls.aspx/Execute2", "{}", function (data) { onsuccess1(data); }, function (data) { onerror1(data); });
            callMyMethod("DynamicControls.aspx/Execute3", "{}", function (data) { onsuccess1(data); }, function (data) { onerror1(data); });
        });
    });
</script>
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产量

此代码生成以下内容:

New call: Fri Jun 22 02:11:17 CDT 2012
  Calling Method: Fri Jun 22 02:11:17 CDT 2012
  Calling Method: Fri Jun 22 02:11:17 CDT 2012
  Calling Method: Fri Jun 22 02:11:17 CDT 2012
    Result: My Name1: 6/22/2012 2:11:19 AM Background thread: 38 Main thread: 48
    Result: My Name2: 6/22/2012 2:11:26 AM Background thread: 50 Main thread: 48
    Result: My Name3: 6/22/2012 2:11:30 AM Background thread: 52 Main thread: 48
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如您所见,代码未经过优化,主线程被锁定,我们设置的最大秒数为7,但在这种情况下,从服务器代码被调用(02:11:17)到最后一次收到回复(2:11:30)13秒过去了.这是因为ASP.Net默认锁定当前Session对象锁定主线程.由于我们在此示例中未使用会话,因此我们可以像这样配置页面:

<%@ Page EnableSessionState="False"
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而新的输出是:

New call: Fri Jun 22 02:13:43 CDT 2012
  Calling Method: Fri Jun 22 02:13:43 CDT 2012
  Calling Method: Fri Jun 22 02:13:43 CDT 2012
  Calling Method: Fri Jun 22 02:13:43 CDT 2012
    Result: My Name1: 6/22/2012 2:13:45 AM Background thread: 52 Main thread: 26
    Result: My Name3: 6/22/2012 2:13:47 AM Background thread: 38 Main thread: 49
    Result: My Name2: 6/22/2012 2:13:50 AM Background thread: 50 Main thread: 51
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现在,从第一个服务器方法调用到收到的最后一个响应只有7秒钟而没有锁定主线程=)

编辑1

如果我的理解是正确的,您需要将一些参数传递给方法并返回数据集以填充标签和文本框.

要将参数传递给PageMethods,这是一种方法:

安装这些Nuget包:

命令类.此类将表示要在post操作中发送到server方法的参数

public class ProcessXmlFilesCommand
{
    public string XmlFilePath { get; set; }

    public ProcessXmlFilesCommand()
    {
    }
}
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而不是返回a DataSet,我认为返回一个更容易和更易于管理的IEnumerable东西,如下所示:

    [WebMethod]
    public static IEnumerable<MyResult> ProcessXmlFiles(ProcessXmlFilesCommand command)
    {
        List<MyResult> results = new List<MyResult>();
        var o = Observable.Start(() =>
        {
            // here do something useful, process your xml files for example
            // use the properties of the parameter command
            results.Add(new MyResult { SomethingInteresting = DateTime.Now.ToString(), FilePath = command.XmlFilePath + "Processed" });
            results.Add(new MyResult { SomethingInteresting = DateTime.Now.ToString(), FilePath = command.XmlFilePath + "Processed" });
            results.Add(new MyResult { SomethingInteresting = DateTime.Now.ToString(), FilePath = command.XmlFilePath + "Processed" });
            Thread.Sleep(2000);
        }, Scheduler.NewThread);
        o.First();
        return results.AsEnumerable();
    }
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该MyResult级代表您要发送回用户的数据

public class MyResult
{
    public string SomethingInteresting { get; set; }
    public string FilePath { get; set; }
}
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在您的ASPX页面中

<script type="text/javascript" src="Scripts/jquery-1.7.2.min.js"></script>
<script type="text/javascript" src="Scripts/json2.min.js"></script>


    <script type="text/javascript">
        function processFiles() {
            var filePath = $("#filePath").val();
            var command = new processFilesCommand(filePath);
            var jsonCommand = JSON.stringify(command);

            $.ajax({
                cache: false,
                type: "POST",
                async: true,
                url: "CustomThreads.aspx/ProcessXmlFiles",
                data: "{'command':" + jsonCommand + "}",
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: function (msg) {
                    onFileProcessedSuccess(msg);
                },
                error: function (exc) {
                    onFileProcessedError(exc);
                }
            });
        }
        function onFileProcessedSuccess(msg) {
            var response = msg.d;
            $.each(response, function (index, myResponse) {
                $("#<%:this.myLabel.ClientID %>").append(myResponse.SomethingInteresting + "<br/>");
            });
        }
        function onFileProcessedError(exc) {
            alert("Error: " + exc.responseText);
        }
        function processFilesCommand(filePath) {
            this.XmlFilePath = filePath;
        }
        $(document).ready(function () {
            $("#processFile").click(processFiles);
        });
    </script>

<input type="text" name="filePath" id="filePath" />
<input type="button" name="processFile" id="processFile" value="Process File" />

<br /><asp:Label ID="myLabel" runat="server" />
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编辑2

这是一种简化的方法

<%@ Page EnableSessionState="False" Language="C#" AutoEventWireup="true" CodeBehind="CustomThreadsSimple.aspx.cs" Inherits="WebApplication1.CustomThreadsSimple" %>
....
<script type="text/javascript" src="Scripts/jquery-1.7.2.min.js"></script>
....
    <script type="text/javascript">
        function makeCall(url, data) {
            $("#<%:this.lblMessage.ClientID %>").append("<br/>Initializing call: " + new Date());
            $.ajax({
                url: url,
                type: "POST",
                dataType: "json",
                contentType: "application/json; charset=utf-8;",
                async: true,
                cache: false,
                data: "{name:'" + data + "'}",
                success: function (msg) {
                    $("#<%:this.lblMessage.ClientID %>").append("<br/>&nbsp;&nbsp;&nbsp;&nbsp;" + msg.d);
                },
                error: function (exc) {
                    alert(exc.responseText);
                }
            });
        }
        $(function () {
            $("#startProcess").click(function () {
                makeCall("CustomThreadsSimple.aspx/Execute1", $("#<%: this.txtData1.ClientID %>").val());
                makeCall("CustomThreadsSimple.aspx/Execute2", $("#<%: this.txtData2.ClientID %>").val());
                makeCall("CustomThreadsSimple.aspx/Execute3", $("#<%: this.txtData3.ClientID %>").val());
            });
        });
    </script>
    <asp:TextBox runat="server" ID="txtData1" />
    <asp:TextBox runat="server" ID="txtData2" />
    <asp:TextBox runat="server" ID="txtData3" />
    <input type="button" name="startProcess" id="startProcess" value="Start execution" />
    <asp:Label ID="lblMessage" runat="server" />
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代码背后

public partial class CustomThreadsSimple : System.Web.UI.Page
{
    [WebMethod]
    public static string Execute1(string name)
    {
        string res = string.Empty;
        Func<string, string> asyncMethod = x =>
        {
            Thread.Sleep(2000);
            return "Res1: " + x +" " + DateTime.Now.ToString() + " Background thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        };

        IAsyncResult asyncRes = asyncMethod.BeginInvoke(name, null, null);
        res = asyncMethod.EndInvoke(asyncRes);
        res += " Main thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        return res;
    }

    [WebMethod]
    public static string Execute2(string name)
    {
        string res = string.Empty;
        Func<string, string> asyncMethod = x =>
        {
            Thread.Sleep(7000);
            return "Res2: " + x + " " + DateTime.Now.ToString() + " Background thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        };

        IAsyncResult asyncRes = asyncMethod.BeginInvoke(name, null, null);
        res = asyncMethod.EndInvoke(asyncRes);
        res += " Main thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        return res;
    }

    [WebMethod]
    public static string Execute3(string name)
    {
        string res = string.Empty;
        Func<string, string> asyncMethod = x =>
        {
            Thread.Sleep(4000);
            return "Res3: " + x + " " + DateTime.Now.ToString() + " Background thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        };

        IAsyncResult asyncRes = asyncMethod.BeginInvoke(name, null, null);
        res = asyncMethod.EndInvoke(asyncRes);
        res += " Main thread: " + Thread.CurrentThread.ManagedThreadId.ToString();
        return res;
    }
}
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