/// <summary>
/// Initializes a new instance of the <see cref="RelayCommand<PingUIOperations>"/> class.
/// </summary>
/// <param name="operationId">The operation id.</param>
/// <param name="canExecute">The can execute method. use <c>null</c> to skip the check.</param>
/// <param name="beginExecute">The begin execute method. Method that should be called when execution
/// completed should be specified in the <see cref="IAsyncCallContext.EndCall"/> inside the <c>beginExecute</c>.</param>
public RelayCommand(UIOperations operationId, BeginAsyncOperationAction beginExecute, Predicate <object> canExecute)
{
this._operationId = operationId;
this._canExecute = canExecute;
this._execute = (prm) => {
this.IsExecuting = null !=
beginExecute(this._asyncContext = new WinAsyncCallContext(this.OperationId, prm), EndAsyncOperation);
};
}
/// <summary>
/// Aborts the execution.
/// </summary>
public virtual bool Abort()
{
WinAsyncCallContext asyncCtx = this._asyncContext;
if (this.IsExecuting && (asyncCtx != null) && this._asyncContext.AbortCall != null)
{
return(asyncCtx.AbortCall(asyncCtx));
}
return(false);
}
void EndAsyncOperation(IAsyncResult asyncResult)
{
this._asyncContext = null; // Clear the cached reference
WinAsyncCallContext asyncCallContext = ((WinAsyncCallContext)(asyncResult.AsyncState));
asyncCallContext.RestoreThreadContext();
if (asyncCallContext.Dispatcher.CheckAccess())
{
this.IsExecuting = false;
asyncCallContext.EndCall(asyncResult);
}
else
{
asyncCallContext.Dispatcher.BeginInvoke(new Action(() => {
this.IsExecuting = false;
asyncCallContext.EndCall(asyncResult);
}));
}
}
