wb.DownloadFileAsync扔" Web客户端不支持并发I / O操作&QUOT。例外 [英] wb.DownloadFileAsync throw "WebClient does not support concurrent I/O operations." exception

问题描述

我需要使用此代码

 ＃地区的活动
 
公共类DownloadProgressChangedEventArg $ B $帮助b {
私人长期_ProgressPercentage; 
私人长期_BytesReceived; 
私人长期_TotalBytesToReceive; 
 
公共DownloadProgressChangedEventArg（长与BytesReceived，长TotalBytesToReceive）
 {
 _BytesReceived =与BytesReceived; 
 _TotalBytesToReceive = TotalBytesToReceive; 
 _ProgressPercentage = *与BytesReceived 100 /（TotalBytesToReceive）; 
} 
 
众长{与BytesReceived获得{返回_BytesReceived; }集合{_BytesReceived =价值; }} 
众长ProgressPercentage {{返回_ProgressPercentage; }集合{_ProgressPercentage =价值; }} 
众长TotalBytesToReceive {{返回_TotalBytesToReceive; }集合{_TotalBytesToReceive =价值; }} 
} 
 
公众委托无效DownloadProgressChangedEventHandler（Api.GetSong.GetObject.Object发件人，DownloadProgressChangedEventArg E）; 
公共事件DownloadProgressChangedEventHandler DownloadProgressChangedEvent; 
 
公共类DownloadCompletedEventArg 
 {
私人布尔_Cancelled; 
私人异常_Error; 
 
公共DownloadCompletedEventArg（异常错误，BOOL取消）
 {
 _Cancelled =取消; 
 _Error =错误; 
} 
 
公共BOOL取消{{返回_Cancelled; }集合{_Cancelled =价值; }} 
公共异常错误{{返回_Error; }集合{_Error =价值; }} 
 
} 
 
公众委托无效DownloadCompletedEventHandler（Api.GetSong.GetObject.Object发件人，DownloadCompletedEventArg E）; 
公共事件DownloadCompletedEventHandler DownloadCompletedEvent; 
 
 #endregion 
 
 Web客户端WB; 
公共无效DownloadFileAsync（Api.GetSong.GetObject.Object对象，字符串FileLocation）
 {
字符串DownloadLink = GetStreamUri（对象）; 
字符串FileTitle = Object.Title +。 + Object.Type; 
字符串FileLocations = Path.Combine（FileLocation，FileTitle）; 
 
如果（！DownloadLink.StartsWith（RTMP））
 {
如果（WB == NULL）
 {
 WB =新的Web客户端（ ）; 
 wb.DownloadFileCompleted + =委托（对象发件人，AsyncCompletedEventArgs E）{DownloadCompletedEvent（对象，新DownloadCompletedEventArg（e.Error，e.Cancelled））; }; 
 wb.DownloadProgressChanged + =委托（对象发件人，DownloadProgressChangedEventArgs E）{DownloadProgressChangedEvent（对象，新DownloadProgressChangedEventArg（e.BytesReceived，e.TotalBytesToReceive））; }; 
} 
 wb.DownloadFileAsync（新的URI（DownloadLink），FileLocations）; 
 
 //抛出：
 // Web客户端不支持并发I / O操作。 
 
} 
，否则
 {
 //Düzenlencek
} 
} 
 
公共无效DownloadFileCancel（）
 {
如果（wb.IsBusy&安培;&安培; WB！= NULL）
 {
 wb.CancelAsync（）; 
} 
} 
  

解决方案

当调用DownloadFileAsync方法，你必须确保它尝试重新下载之前完成。

的这个答案会帮助你。

I need help with this code

#region Events

public class DownloadProgressChangedEventArg
{
    private long _ProgressPercentage;
    private long _BytesReceived;
    private long _TotalBytesToReceive;

    public DownloadProgressChangedEventArg(long BytesReceived, long TotalBytesToReceive)
    {
        _BytesReceived = BytesReceived;
        _TotalBytesToReceive = TotalBytesToReceive;
        _ProgressPercentage = BytesReceived * 100 / (TotalBytesToReceive);
    }

    public long BytesReceived { get { return _BytesReceived; } set { _BytesReceived = value; } }
    public long ProgressPercentage { get { return _ProgressPercentage; } set { _ProgressPercentage = value; } }
    public long TotalBytesToReceive { get { return _TotalBytesToReceive; } set { _TotalBytesToReceive = value; } }
}

public delegate void DownloadProgressChangedEventHandler(Api.GetSong.GetObject.Object Sender, DownloadProgressChangedEventArg e);
public event DownloadProgressChangedEventHandler DownloadProgressChangedEvent;

public class DownloadCompletedEventArg
{
    private bool _Cancelled;
    private Exception _Error;

    public DownloadCompletedEventArg(Exception Error, bool Cancelled)
    {
        _Cancelled = Cancelled;
        _Error = Error;
    }

    public bool Cancelled { get { return _Cancelled; } set { _Cancelled = value; } }
    public Exception Error { get { return _Error; } set { _Error = value; } }

}

public delegate void DownloadCompletedEventHandler(Api.GetSong.GetObject.Object Sender, DownloadCompletedEventArg e);
public event DownloadCompletedEventHandler DownloadCompletedEvent;

#endregion

WebClient wb;
public void DownloadFileAsync(Api.GetSong.GetObject.Object Object, String FileLocation)
{
    String DownloadLink = GetStreamUri(Object);
    String FileTitle = Object.Title + "." + Object.Type;
    String FileLocations = Path.Combine(FileLocation,FileTitle);

    if (!DownloadLink.StartsWith("rtmp"))
    {
        if (wb == null)
        {
            wb = new WebClient();
            wb.DownloadFileCompleted += delegate(object sender, AsyncCompletedEventArgs e) { DownloadCompletedEvent(Object, new DownloadCompletedEventArg(e.Error, e.Cancelled)); };
            wb.DownloadProgressChanged += delegate(object sender, DownloadProgressChangedEventArgs e) { DownloadProgressChangedEvent(Object, new DownloadProgressChangedEventArg(e.BytesReceived, e.TotalBytesToReceive)); };
        }
        wb.DownloadFileAsync(new Uri(DownloadLink), FileLocations);

        //throw:
        //WebClient does not support concurrent I/O operations.

    }
    else
    {
        //Düzenlencek
    }
}

public void DownloadFileCancel()
{
    if (wb.IsBusy && wb != null)
    {
        wb.CancelAsync();
    }
}

解决方案

When calling DownloadFileAsync method you have to make sure it completes before trying to download again.

This answer will help you.

这篇关于wb.DownloadFileAsync扔" Web客户端不支持并发I / O操作&QUOT。例外的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！