This example illustrates how to add a custom function to the designer and use it in the dashboard template.

First, you need to add the StiMvcDesigner component to the view page. Also you need to pass the StiMvcDesignerOptions object to the constructor and set the all required actions:

@using Stimulsoft.Report.Mvc;

...

@Html.Stimulsoft().StiMvcDesigner(new StiMvcDesignerOptions()
{
    Actions =
    {
        GetReport = "GetReport",
        DesignerEvent = "DesignerEvent"
    }
})

Now you need to open the DesignerController code and add the resulting methods for the specified actions:

public ActionResult GetReport()
{
	// Create the dashboard object
	var report = StiReport.CreateNewDashboard();

	// Load dashboard template
	report.Load(Server.MapPath("~/Dashboards/DashboardChristmas.mrt"));

	// Return template to the Designer
	return StiMvcDesigner.GetReportResult(report);
}

public ActionResult DesignerEvent()
{
	return StiMvcDesigner.DesignerEventResult();
}

Add a custom function in the controller, it must be static. For example, this would be a function MySum() that sums all the values in the list:

public static decimal MySum(object value)
{
	if (!ListExt.IsList(value))
		return Stimulsoft.Base.Helpers.StiValueHelper.TryToDecimal(value);

	return Stimulsoft.Data.Functions.Funcs.SkipNulls(ListExt.ToList(value))
		.TryCastToDecimal()
		.Sum();
}

To add a function to the designer's dictionary, it is enough to call the special StiFunctions.AddFunction() method, this can be done in the static constructor of the controller. In the arguments of this method you should specify all the required parameters - category, function name, description, types of input and return parameters:

static DesignerController()
{
	// How to add my function
	StiFunctions.AddFunction("MyCategory", "MySum",
	"description", typeof(DesignerController),
	typeof(decimal), "Calculates a sum of the specified set of values.",
	new[] { typeof(object) },
	new[] { "values" },
	new[] { "A set of values" }).UseFullPath = false;
}

In the screenshot below you can see the result of the sample code: