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copied!<p>Async Await keywords are one way to solve your situation. However your actual problem is you dont understand how the <code>GetAsync</code> call works. When you say:</p> <pre><code>public static long CheckIfUserExist() { long UserID = -1; client.GetAsync("me"); client.GetCompleted += (o, e) => { // some code if (Convert.ToInt64(eargs.Result) == 0) { UserID = Convert.ToInt64(eargs.Result); } return UserID; } } </code></pre> <p>It is equivalent to:</p> <pre><code> public static long CheckIfUserExist() { long UserID = -1; client.GetAsync("me"); client.GetCompleted += MyEventHandler; } void MyEventHandler(object sender, SomeEventArgs e) { // some code if (Convert.ToInt64(eargs.Result) == 0) { UserID = Convert.ToInt64(eargs.Result); } return UserID; // <-- WHAT IS POINT OF RETURNING UserID FROM HERE?? // method maybe running on some other thread asynchronously to UI thread } </code></pre> <p>There are two possibilities for you: If your <code>client</code> object's <code>GetCompleted</code> event occurs on the UI thread you can do this:</p> <pre><code> client.GetCompleted += (o, e) => { // some code if (Convert.ToInt64(eargs.Result) == 0) { UserID = Convert.ToInt64(eargs.Result); } // your logic here if (UserID == -1) // WRONG RESULT <--- else // RIGHT RESULT <--- } </code></pre> <p>If <code>GetCompleted</code> event does not occur on UI thread:</p> <pre><code>client.GetCompleted += (o, e) => { // some code if (Convert.ToInt64(eargs.Result) == 0) { UserID = Convert.ToInt64(eargs.Result); } // let UI thread know we've got the result Dispatcher.Invoke( (Action)(() => { NotifyUIThread(UserID) } )); } ... void NotifyUIThread(long UserId) //This runs on UI thread { if (UserID == -1) // WRONG RESULT <--- else // RIGHT RESULT <--- } </code></pre> <p>Also, take care there you subscribe to event before you call <code>GetAsync</code></p> <pre><code>client.GetCompleted += (o, e) => { ... } //subscribe first client.GetAsync("me"); // call GetAsync later </code></pre> <p>If on WP7 - you may have problem with <code>Dispatcher.Invoke</code> see this: <a href="https://stackoverflow.com/questions/4247729/cant-use-dispatcher-on-wp7">Can't use dispatcher on WP7</a></p>

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