Specified argument was out of the range of valid values. Parameter name: childIndex

[Vuyiswa]

Good Day

i am using the telerik Report , i am trying to load the Report on page load in Silverlight. this used to work perfectly in a Silverlight Page, now i am using  the report in a SilverlightChild Window and whenever my code reaches this pl

var layoutRoot = (FrameworkElement)VisualTreeHelper.GetChild(reportViewer, 0);

it fails with the Error

Specified argument was out of the range of valid values. Parameter name: childIndex

so to make sure that it does not find the elements i used the code like this

if (VisualTreeHelper.GetChildrenCount(reportViewer) > 0)
            {
                var layoutRoot = (FrameworkElement)VisualTreeHelper.GetChild(reportViewer, 0);
                var viewerModel = (ReportViewerModel)layoutRoot.DataContext;
                var refreshCommand = viewerModel.RefreshReportCommand;
                if (refreshCommand.CanExecute(null))
                {
                    refreshCommand.Execute(null);
                }
            }

I see it does not find an element.

Thanks

[Steve]

Hello Vuyiswa,

As explained in one of your other threads, this could happen if the report viewer template has not yet been created (e.g. invoking the extension method in the window/user control constructor). To make sure the template is available use OnApplyTemplate e.g.:

Copy Code

public partial class MainPage : UserControl
   {
       public MainPage()
       {
           InitializeComponent();
       }

       public override void OnApplyTemplate()
       {
           base.OnApplyTemplate();
           this.ReportViewer1.RefreshReport();
       }
   }

   static class ReportViewerExtensions
   {
       public static void RefreshReport(this ReportViewer reportViewer)
       {
           var layoutRoot = (FrameworkElement)VisualTreeHelper.GetChild(reportViewer, 0);
           var viewerModel = (ReportViewerModel)layoutRoot.DataContext;
           var refreshCommand = viewerModel.RefreshReportCommand;
           if (refreshCommand.CanExecute(null))
           {
               refreshCommand.Execute(null);
           }
       }
   }

All the best,
Steve
the Telerik team