/// <summary>
/// Invokes a web method asynchronously.
/// </summary>
/// <param name="methodName">Web method name.</param>
/// <param name="asyncCallState">Call state handle.
/// Upon return, may be used to cancel the call</param>
/// <param name="parameters">Web method parameters.</param>
/// <param name="callback">Callback method to process the result.</param>
/// <seealso cref="CancelAsync(AsyncCallState)"/>
public void InvokeAsync(
string methodName,
AsyncCallState asyncCallState,
Delegate callback,
params object[] parameters)
{
InvokeAsync(methodName, asyncCallState, null, callback, parameters);
}
/// <summary>
///.Cancel an asynchronous call if it is not completed already.
/// </summary>
/// <param name="asyncCallState">Async call state.</param>
public void CancelAsync(AsyncCallState asyncCallState)
{
if (asyncCallState.PendingCall == null)
{
return;
}
CancelAsync(asyncCallState.PendingCall);
asyncCallState.PendingCall = null;
}
/// <summary>
/// Invokes a web method asynchronously.
/// </summary>
/// <param name="methodName">Web method name.</param>
/// <param name="asyncCallState">Call state handle.
/// Upon return, may be used to cancel the call</param>
/// <param name="parameters">Web method parameters.</param>
/// <param name="callback">Callback method to process the result.</param>
/// <param name="exceptionHandler">Fail handler.</param>
/// <seealso cref="CancelAsync(AsyncCallState)"/>
public void InvokeAsync(
string methodName,
AsyncCallState asyncCallState,
Action <Exception> exceptionHandler,
Delegate callback,
params object[] parameters)
{
#if DEBUG
var sw = Stopwatch.StartNew();
#endif
if (asyncCallState != null)
{
#if DEBUG
Debug.WriteLineIf(TS.TraceVerbose && asyncCallState.PendingCall != null,
string.Format("Cancelling async call {0}/{1}",
Url, methodName), TS.DisplayName);
#endif
CancelAsync(asyncCallState);
}
var exceptionCallback = exceptionHandler ?? delegate(Exception ex)
{
if (ex is WebException)
{
var webException = (WebException)ex;
// Request cancelled.
//
if (webException.Status == WebExceptionStatus.RequestCanceled)
{
OnWebOperationCancelled(methodName, parameters);
return;
}
}
// Check for retry.
//
if (OnWebOperationException(methodName, parameters, ex))
{
InvokeAsync(methodName, asyncCallState, exceptionHandler, callback, parameters);
}
};
System.Threading.SendOrPostCallback sendCallback = delegate(object obj)
{
#if DEBUG
Debug.WriteLineIf(TS.TraceVerbose,
string.Format("Async call {0}/{1} = {2} msec.",
Url, methodName, sw.ElapsedMilliseconds), TS.DisplayName);
#endif
var ea = (InvokeCompletedEventArgs)obj;
if (ea.Error != null)
{
// Internal redirection
//
if (ea.Error is WebException && ((WebException)ea.Error).Status == WebExceptionStatus.ReceiveFailure)
{
InvokeAsync(methodName, asyncCallState, exceptionHandler, callback, parameters);
}
else
{
exceptionCallback(ea.Error);
}
}
else if (ea.Cancelled || (asyncCallState != null && ea.UserState != asyncCallState.PendingCall))
{
exceptionCallback(new WebException(methodName, WebExceptionStatus.RequestCanceled));
}
else
{
callback.DynamicInvoke(AcceptChanges(ea.Results));
}
if (asyncCallState != null && ea.UserState == asyncCallState.PendingCall)
{
asyncCallState.PendingCall = null;
}
};
object cookie = new CompoundValue(methodName, parameters);
if (asyncCallState != null)
{
asyncCallState.PendingCall = cookie;
}
InvokeAsync(methodName, parameters, sendCallback, cookie);
}
