or
var reportViewerModel = reportViewer.DataContext as ReportViewerModel;var layoutRoot = (FrameworkElement)VisualTreeHelper.GetChild(this.reportViewer, 0);var rvm = (ReportViewerModel)(layoutRoot.DataContext);this.Filters.Add("=Fields.column1", Telerik.Reporting.Data.FilterOperator.Like, "%GRP:**All Admins**,%");this.textBox6.Value = "{Fields.UserName}\r\nCLIENT SIGN-IN SHEET";