.NET CF WebService ObjectDisposedException

我想解决我的一个智能设备项目（Windows Mobile 6.5设备上的.NET CF 3.5）的问题。.NET CF WebService ObjectDisposedException

该代码试图不断调用web服务调用来获取一些数据并在窗体中使用它。在使用过程中，对于特定情况，会抛出ObjectDisposedException并导致应用程序崩溃。堆栈跟踪是

System.ObjectDisposedException was unhandled 
Message="ObjectDisposedException" 
ObjectName="" 
StackTrace: 
     at System.Threading.Timer.throwIfDisposed() 
     at System.Threading.Timer.Change(UInt32 dueTime, UInt32 period) 
     at System.Threading.Timer.Change(Int32 dueTime, Int32 period) 
     at System.Net.HttpWebRequest.startReadWriteTimer() 
     at System.Net.HttpWebRequest.ConnectionClient.Read(Byte[] data, Int32 offset, Int32 length) 
     at System.Net.HttpReadStream.NetworkRead(Byte[] data, Int32 offset, Int32 length) 
     at System.Net.ChunkedReadStream.fillBuffer() 
     at System.Net.ChunkedReadStream.getLine() 
     at System.Net.ChunkedReadStream.doRead(Byte[] data, Int32 offset, Int32 length) 
     at System.Net.HttpReadStream.ReadToDrain(Byte[] buffer, Int32 offset, Int32 length) 
     at System.Net.HttpReadStream.doClose() 
     at System.Net.HttpReadStream.Finalize()

我看了很多博客和论坛，包括这一点，并提出解决方案似乎是关闭的请求流和要求，得到响应之前。

requestStream = webRequest.GetRequestStream(); 
requestStream.Close(); // WE NEED THIS LINE in order to avoid the ObjectDisposedException.

但这并不能帮助我的情况。如果requestStream在写入数据流之前关闭，那么它不会执行任何操作。如果我在得到响应后关闭，则会抛出InvalidOperationException。

以下是我的代码：

Reference.cs

[System.Diagnostics.DebuggerStepThroughAttribute()] 
[System.ComponentModel.DesignerCategoryAttribute("code")] 
[System.Web.Services.WebServiceBindingAttribute(Name="ProductResolveServiceSOAP11Binding", Namespace="urn:ProductResolveService")] 
[System.Xml.Serialization.XmlIncludeAttribute(typeof(Exception))] 
public partial class ProductResolveService : System.Web.Services.Protocols.SoapHttpClientProtocol { 

    /// <remarks/> 
    public ProductResolveService() { 
     this.Url = "http://172.26.37.115:8080/axis/services/ProductResolveService"; 
    } 

    /// <remarks/> 
    [System.Web.Services.Protocols.SoapDocumentMethodAttribute("urn:getResolvedEpcs", RequestNamespace="http://services.axis.oatsystems.com", ResponseNamespace="http://services.axis.oatsystems.com", Use=System.Web.Services.Description.SoapBindingUse.Literal, ParameterStyle=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)] 
    [return: System.Xml.Serialization.XmlElementAttribute("return", IsNullable=true)] 
    public ResolvedProductList getResolvedEpcs([System.Xml.Serialization.XmlElementAttribute(IsNullable=true)] EpcToResolve message) { 
     object[] results = this.Invoke("getResolvedEpcs", new object[] { 
        message}); 
     return ((ResolvedProductList)(results[0])); 
    } 

    /// <remarks/> 
    public System.IAsyncResult BegingetResolvedEpcs(EpcToResolve message, System.AsyncCallback callback, object asyncState) { 
     return this.BeginInvoke("getResolvedEpcs", new object[] { 
        message}, callback, asyncState); 
    } 

    /// <remarks/> 
    public ResolvedProductList EndgetResolvedEpcs(System.IAsyncResult asyncResult) { 
     object[] results = this.EndInvoke(asyncResult); 
     return ((ResolvedProductList)(results[0])); 
    } 
}

Form1.cs的

using System; 
using System.Collections.Generic; 
using System.Net; 
using System.Threading; 
using System.Web.Services.Protocols; 
using System.Windows.Forms; 
using NFEHandlingProject.StatusService; 
using System.IO; 
using MVProductResolveService; 


namespace NFEHandlingProject 
{ 
    public partial class Form1 : Form 
    { 
     private Thread resolveThread; 
     int counter = 0; 

     public Form1() 
     { 
      InitializeComponent(); 
     } 

     private void btnStart_Click(object sender, EventArgs e) 
     { 
      if (resolveThread == null) 
      { 
       this.BeginInvoke((Action)delegate { lstbxStatusMsgs.Items.Add("Resolve Product: Creating Thread"); lstbxStatusMsgs.SelectedIndex = lstbxStatusMsgs.Items.Count - 1; }); 

       resolveThread = new Thread(new ThreadStart(GetEpcProductMapping)); 
       resolveThread.IsBackground = true; 
       resolveThread.Priority = ThreadPriority.BelowNormal; 

       resolveThread.Start(); 
      } 
     } 

     object syncRoot2 = new object(); 
     bool resolving = false; 

     private void GetEpcProductMapping() 
     { 
      lock (syncRoot2) 
      { 
       if (resolving) 
       { 
        return; 
       } 

       resolving = true; 
      } 

      while (resolving) 
      { 
       using (ProductResolveService2 productResolveService = new ProductResolveService2()) 
       { 
        EpcToResolve epcToResolve = null; 

        try 
        { 
         this.BeginInvoke((Action)delegate { lstbxStatusMsgs.Items.Add("Resolve Product: Resolving..."); lstbxStatusMsgs.SelectedIndex = lstbxStatusMsgs.Items.Count - 1; }); 

         productResolveService.Url = "http://172.26.37.115:8080/axis/services/ProductResolveService?wsdl"; 

         productResolveService.Timeout = 60000; 

         // The input object that is sent to xpress 
         epcToResolve = new EpcToResolve(); 

         string epcBase = "3410402AEA0000000000"; 
         int baseDec = Convert.ToInt32("1000", 16); 

         // Creating the input of epc's baed on the ResolveBatchSize and number epcs's that needs to be resolved at xpress 
         string[] epcs = new string[1]; 
         for (int i = 0; i < 1; i++) 
         { 
          int epcDec = baseDec + i; 
          epcs[i] = epcBase + epcDec.ToString("X"); 
         } 

         // setting the epc list which is the input that is sent to xpress 
         epcToResolve.epcList = epcs; 

         //pass the flag to check if say whether the productInformation or just the product_id is resolved 
         epcToResolve.returnOnlyProductId = false; 

         //return productResolveService.getResolvedEpcs(epcToResolve); 
         productResolveService.getResolvedEpcs(epcToResolve); 
         this.BeginInvoke((Action)delegate { lstbxStatusMsgs.Items.Add("Resolved"); lstbxStatusMsgs.SelectedIndex = lstbxStatusMsgs.Items.Count - 1; }); 
        } 
        catch (SoapHeaderException) 
        { 
         // do nothing 
        } 
        catch (SoapException se) 
        { 
         this.BeginInvoke((Action)delegate { lstbxStatusMsgs.Items.Add("Problem resolving products at xpress"); lstbxStatusMsgs.SelectedIndex = lstbxStatusMsgs.Items.Count - 1; }); 
        } 
        catch (WebException we) 
        { 
         // get the reason for the exception 
         WebExceptionStatus status = we.Status; 
         String description = we.Message; 

         WebResponse response = we.Response; 
         if (response != null) 
         { 
          Stream respStream = response.GetResponseStream(); 

          if (respStream != null) 
          { 
           respStream.Close(); 
           respStream.Dispose(); 
           respStream = null; 
          } 
          // close the response 
          response.Close(); 
          response = null; 
         } 
         // Case when there is no connectivity. Just display an error message to the user to indicate that there is no connectivity. 
         this.BeginInvoke((Action)delegate { lstbxStatusMsgs.Items.Add("Resolve Product: There is no connectivity to xpress"); lstbxStatusMsgs.SelectedIndex = lstbxStatusMsgs.Items.Count - 1; }); 
        } 
        catch (ThreadAbortException) 
        { 
         // Do nothing. Do not log 
        } 
        catch (System.Exception e) 
        { 
         this.BeginInvoke((Action)delegate { lstbxStatusMsgs.Items.Add("An exception occured when fetching data from xpress"); lstbxStatusMsgs.SelectedIndex = lstbxStatusMsgs.Items.Count - 1; }); 
        } 

        try 
        { 
         Thread.Sleep(200); 
        } 
        catch 
        { 
        } 
       } 
      } 

      resolving = false; 
     } 

     private void btnStop_Click(object sender, EventArgs e) 
     { 
      if (resolveThread != null && resolving) 
      { 
       resolveThread.Abort(); 
       resolveThread.Join(); 
       resolveThread = null; 
       resolving = false; 

       this.BeginInvoke((Action)delegate { lstbxStatusMsgs.Items.Add("Resolve Product: Stopped Thread"); lstbxStatusMsgs.SelectedIndex = lstbxStatusMsgs.Items.Count - 1; }); 
      } 
     } 
    } 
}

在点击开始按钮的形式，在创建线程，并保持通话web服务，当停止被调用时，线程停止。重复的启动和停止会导致ObjectDisposedException（这是我重现此异常的方式）。

任何有关这方面的帮助将高度赞赏，因为我几天来一直在试图解决这个问题。

感谢塞特希

来源

2012-05-29 Senthil

你有没有确定究竟在何处的错误是从你的代码来吗？它是否来自getResolvedEpcs的调用，因为消息在被访问之前被丢弃？有没有更多的堆栈跟踪，或者有错误的内部异常？ – Nanhydrin

这是从.NET代码，而不是从我的代码。到目前为止，我的解释是我不应该重用存根（ProductResolveService），我需要每次关闭请求流和响应流。如果没有这样做，那么会有一个Timer（用于异步调用）唤醒并试图访问请求/响应流（我不知道哪一个），并发现它已经处理，因此会抛出此异常。我所做的调用是同步的，我不知道为什么Timer仍在使用中。 – Senthil

错误只发生在您停止或仅仅是随机发生之后？ – Nanhydrin

这是一个很老的帖子。然而，我想在这里记录我的答案，任何仍在寻找答案的机构。

两个选项：

移动到WCF客户是更容易和更清洁。

使用下面的解决方案。

public class ExtendedDataImport : DataImport.DataImport 
{ 
    private WebRequest webRequest; 
    private WebResponse webResponse; 

    /// <summary> 
    /// This method overrides the generated method and sets parameters so that HTTP 1.0 
    /// is used (without chunking). If left with default parameters it 
    /// sometimes fails. 
    /// </summary> 
    protected override WebRequest GetWebRequest(Uri uri) 
    { 
     webRequest = base.GetWebRequest(uri); 
     ((HttpWebRequest)webRequest).KeepAlive = false; 
     ((HttpWebRequest)webRequest).ProtocolVersion = HttpVersion.Version10; 
     return webRequest; 
    } 

    protected override WebResponse GetWebResponse(WebRequest request) 
    { 
     webResponse = base.GetWebResponse(request); 
     return webResponse; 
    } 

    public void Close() 
    { 
     if (webResponse != null) 
     { 
      Stream responseStream = webResponse.GetResponseStream(); 
      responseStream.Close(); 
      responseStream.Dispose(); 
      responseStream = null; 
      webResponse.Close(); 
      webResponse = null; 
     } 

     if (webRequest != null) 
     { 
      // Aborting the WebRequest, cleans up the webrequest and 
      // stops the timer which causes the ObjectDisposedException 
      try 
      { 
       webRequest.Abort(); 
       webRequest = null; 
      } 
      catch (ObjectDisposedException ex) 
      { 
       // Ignoring the object disposed exception as mentioned in the follwoing link 
       //http://social.msdn.microsoft.com/Forums/en/netfxcompact/thread/8f21514c-9b7c-40d3-96c9-794c0dc167fe 
      } 
     } 
    } 

    protected override void Dispose(bool disposing) 
    { 
     Close(); 
     base.Dispose(disposing); 
    } 
}

来源

2017-01-25 07:10:35 Senthil

.NET CF WebService ObjectDisposedException

回答

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