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How to add interactivity to a report using action event handlers in WPF Report Viewer.

Environment

Product Progress® Telerik® Reporting
Report Viewer WPF Report Viewer

Desciption

The report viewers provide handlers for three types of events that are associated with interactive actions – Executing, Enter and Leave.

In this article we will show how to use these events to add more interactivity and allow further customization for your reports.

We will use the CSharp.NetFramework.WpfIntegrationDemo project that is shipped with your Telerik Reporting installation and is part of the CSharp.ReportExamples.VSxxxx solution that can be found at the following path:

C:\Program Files (x86)\Progress\\Examples\CSharp.

The report we chose for this example is part of our ReportingLibrary and is called PopulationDensity. It displays a choropleth based on the world population by countries. We will show how to change the colors and display an informational tooltip for the country under the mouse cursor, using a Custom action.

Additionally, we will show you how to cancel a NavigateToUrl action before it is executed, depending on a confirmation dialog.

Solution

  • Start Visual Studio, open the solution file and locate the CSharp.ReportLibrary project. Navigate to Choropleth/PopulationDensity.cs file and open it. Add the following code snippet in the report constructor right after the InitializeComponent() call:
textBoxTitle.Action = new NavigateToUrlAction()
{
     Url = "https://en.wikipedia.org/wiki/Population_density" ,
     Target = UrlTarget.NewWindow
};
var customAction = new CustomAction();
customAction.Parameters.Add( new Parameter( "country" , "=Fields.CNTRY_NAME" ));
customAction.Parameters.Add( new Parameter( "area" , "=Fields.SQKM" ));
customAction.Parameters.Add( new Parameter( "population" , "=Fields.POP_CNTRY" ));
customAction.Parameters.Add( new Parameter( "populationDensity" , "=CInt(Fields.POP_CNTRY / Fields.SQKM)" ));
shapeMapSeries1.SeriesGroup.Action = customAction;

This code modifies the report definition, adding NavigateToUrlAction instance to the title text box and CustomAction instance with four parameters to the ShapeMap series group, which means that every data point (every shape in the choropleth) will trigger a custom action.

Please note that modifying the report definition programmatically is not recommended and we use it here for demonstration purpose - otherwise we strongly advise to use the Report Designer for such tasks.

  • Open the CSharp.NetFramework.WpfIntegrationDemo project and locate Window1.xaml.cs file. Add the following two private fields to the Window1 body (we will explain about them later):
System.Windows.Media.Brush fillBrush;
System.Windows.Media.Brush stroke;
  • Add the following code snippet in the report viewer constructor after InitializeComponent() line:
this .ReportViewer1.ReportSource = new Telerik.Reporting.TypeReportSource()
{
     TypeName = typeof (Telerik.Reporting.Examples.CSharp.Choropleth.PopulationDensity).AssemblyQualifiedName
};
this .ReportViewer1.InteractiveActionEnter += Choropleth_ActionEnter;
this .ReportViewer1.InteractiveActionLeave += Choropleth_ActionLeave;
this .ReportViewer1.InteractiveActionExecuting += Choropleth_ActionExecuting;

// This code block sets the report viewer's ReportSource property and creates the handlers to the interactive actions.
  • To create the method for the Choropleth_ActionEnter handler, add the following code snippet to the .cs file:
void Choropleth_ActionEnter( object sender, Telerik.ReportViewer.Wpf.InteractiveActionEventArgs args)
{
     if (args.Action.ReportItemName == "textBoxTitle" )
     {
         var b = args.Element as System.Windows.Controls.Border;
         if ( null != b)
         {
             b.BorderThickness = new Thickness(0, 0, 0, 1.33);
             b.BorderBrush = System.Windows.Media.Brushes.RoyalBlue;
         }
     }
     else
     {
         var p = args.Element as System.Windows.Shapes.Path;
         if (p != null )
         {
             this .fillBrush = p.Fill;
             this .stroke = p.Stroke;
             p.Stroke = System.Windows.Media.Brushes.SaddleBrown;
             p.Fill = System.Windows.Media.Brushes.MediumSeaGreen;
         }
         var action = args.Action as Telerik.Reporting.Processing.CustomAction;               
         if ( null != action)
         {
             p.ToolTip = this .GetCountryInfo(action.Parameters);
         }
     }
}
string GetCountryInfo(System.Collections.Generic.IDictionary< string , object > paramValues)
{
     var strB = new System.Text.StringBuilder();
     strB.AppendFormat( "Country: {0}{1}" , paramValues[ "country" ], Environment.NewLine);
     strB.AppendFormat( "Area: {0} km²{1}" , paramValues[ "area" ], Environment.NewLine);
     strB.AppendFormat( "Population: {0}{1}" , paramValues[ "population" ], Environment.NewLine);
     strB.AppendFormat( "Density: {0} ppl/km²" , paramValues[ "populationDensity" ]);
     return strB.ToString();
}

This code is executed when the mouse enters the interactive action area. Since it is fired for every action, we need to check the ReportItemName value so our code will react accordingly. If we are hovering over the title text box, the action element will be of System.Windows.Controls.Border type and we can setup the bottom border line, underscoring the text.

In any other case, the event should be raised when the cursor is over a map data point, which means that the current element will be of a System.Windows.Shapes.Path type. The current shape fill and stroke is preserved in the fields created earlier so they will be restored when the mouse cursor leaves the current shape. The action in the arguments is cast to CustomAction and the current element’s tooltip is set to the output of the GetCountryInfo() method.

  • To create the method for the Choropleth_ActionLeave handler, add the following code snippet to the .cs file:
void Choropleth_ActionLeave( object sender, Telerik.ReportViewer.Wpf.InteractiveActionEventArgs args)
{
     if (args.Action.ReportItemName == "textBoxTitle" )
     {
         var b = args.Element as System.Windows.Controls.Border;
         if ( null != b)
         {
             b.BorderThickness = new Thickness(0);
             b.BorderBrush = null ;
         }
     }
     else
     {
         var p = args.Element as System.Windows.Shapes.Path;
         if (p != null )
         {
             p.Fill = this .fillBrush;
             p.Stroke = this .stroke;
         }
     }
}

// The code here restores the default state of the framework elements, changed during the Choropleth\_ActionEnter  event.
  • To create the method for the Choropleth_ActionExecuting handler, add the following code snippet to the .cs file:
void Choropleth_ActionExecuting( object sender, Telerik.ReportViewer.Wpf.InteractiveActionCancelEventArgs args)
{
     if (args.Action.ReportItemName == "textBoxTitle" )
     {
         args.Cancel = MessageBox.Show( "Do you want to learn more about the world population density?" , "More information" , MessageBoxButton.YesNo) != MessageBoxResult.Yes;
     }
     else
     {
         var customAction = (Telerik.Reporting.Processing.CustomAction)args.Action;
         string countryName = customAction.Parameters[ "country" ].ToString();
         var msg = string .Format( "{0}{1}{1}Do you want to learn more about {2} ?" ,
             this .GetCountryInfo(customAction.Parameters),
             Environment.NewLine,
             countryName);

         if (MessageBox.Show(msg, "More information" , MessageBoxButton.YesNo) == MessageBoxResult.Yes)
         {
             System.Diagnostics.Process.Start( string .Format( "https://en.wikipedia.org/wiki/{0}" , countryName));
         }
     }
}

Again, we need to check the ReportItemName property to be sure which report item raised the event. If the action is triggered from the title text box, the viewer will display a confirmation box and its result will be assigned to the Cancel property, so the NavigateToUrl action will not be executed if Cancel is set to true. However, when using a CustomAction, the Cancel property doesn’t affect the workflow, so in this case we will display a confirmation box with some details and will open a browser window, navigating to a wiki page of the current country, whose name is obtained through the CustomAction parameters.

When you're done, run the project and hover your mouse over the choropleth. It should look like the one below:

Choropleth

Notes

In this article we demonstrated how to add interactivity and customizations to a report with a few lines of code. This approach can be used in all the current report viewers with slight modifications due to the rendering technology.

See Also

Designing Reports - Actions

Custom Action

How to add interactivity to a report using action event handlers in WinForms report viewer

How to add interactivity to a report using action event handlers in HTML5-based report viewers

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