Integrating Visio with SharePoint - Visio Services Quick Guide - page 86

{
public class VisioDataService : AddonDataHandler, IAsyncResult
{
private object _asyncState;
private bool _completeStatus;
WaitHandle IAsyncResult.AsyncWaitHandle
{
get { return null; }
}
object IAsyncResult.AsyncState
{
get { return _asyncState; }
}
bool IAsyncResult.IsCompleted
{
get { return this._completeStatus; }
}
bool IAsyncResult.CompletedSynchronously
{
get { return false; }
}
public override IAsyncResult BeginGetData(HttpContext
httpContext, AsyncCallback callback, object asyncState)
{
_asyncState = asyncState;
ThreadPool.QueueUserWorkItem(new WaitCallback(GetData),
callback);
return this;
}
public override DataSet EndGetData(IAsyncResult asyncResult)
{
return this.Data;
}
public override void Cancel()
{
// Not implemented
}
private void GetData(object state)
{
AsyncCallback asyncCallback = (AsyncCallback)state;
try
{
ServerStatusClient oServerStatus = new ServerStatusClient();
DataTable dt = oServerStatus.GetServerStatusDetails();
this.Data.Reset();
this.Data.Tables.Add(dt);
this.Data.AcceptChanges();
}