public async Task DescribeAsync() { try { if (this.ImageUrl != null) { this.AnalysisResult = await VisionServiceHelper.DescribeAsync(this.ImageUrl); } else if (this.GetImageStreamCallback != null) { this.AnalysisResult = await VisionServiceHelper.DescribeAsync(this.GetImageStreamCallback); } } catch (Exception e) { this.AnalysisResult = new Microsoft.ProjectOxford.Vision.Contract.AnalysisResult(); if (this.ShowDialogOnFaceApiErrors) { await ErrorTrackingHelper.GenericApiCallExceptionHandler(e, "Vision API failed."); } } }