WinForms Spreadsheet Control – Custom Functions

In the recent release v2013.1 of the DevExpress WinForms Subscription, we introduced a brand new Spreadsheet Control. We are hard at work adding features to it and in v13.1.5 we’ve added support for Custom Functions

To register a Custom Function, we simply need to implement a CustomFunction interface and add the object to workbook’s CustomFunctions collection.

Here is a sample implementation a custom function SPHEREMASS(radius, density). The function calculates the mass of a sphere given it’s radius and density. If parameter density is not specified, the density of water (1000 kg/m3) is assumed.

if (!workbook.CustomFunctions.Contains(customFunction.Name))

    workbook.CustomFunctions.Add(customFunction);

publicclassSphereMassFunction : ICustomFunction

{

    conststring functionName = "SPHEREMASS";

    readonlyParameterInfo[] functionParameters;

    public SphereMassFunction()

    {  

        // Missing optional parameters do not result in error message.

        this.functionParameters = newParameterInfo[] { newParameterInfo(ParameterType.Value, ParameterAttributes.Required),

            newParameterInfo(ParameterType.Value, ParameterAttributes.Optional)};

    }

    publicstring Name { get { return functionName; } }

    ParameterInfo[] CustomFunction.Parameters { get { return functionParameters; } }

    ParameterTypeCustomFunction.ReturnType { get { returnParameterType.Value; } }

    // Reevaluate cells on every recalculation.

    boolCustomFunction.Volatile { get { returnfalse; } }

    ParameterValueCustomFunction.Evaluate(IList<ParameterValue> parameters, EvaluationContext context)

    {

        double radius;

        double density = 1000;

        ParameterValue radiusParameter;

        ParameterValue densityParameter;

        if (parameters.Count == 2)

        {

            densityParameter = parameters[1];

            if (densityParameter.IsError)

                return densityParameter;

            else

                density = densityParameter.NumericValue;               

        }

        radiusParameter = parameters[0];

        if (radiusParameter.IsError)

            return radiusParameter;

        else

            radius = radiusParameter.NumericValue;

        return (4 * Math.PI) / 3 * Math.Pow(radius,3) * density;

    }

    stringCustomFunction.GetName(CultureInfo culture)

    {

        return functionName;

    }

Build v13.1.5 is available for immediate download from the Download Manager.

Cheers,

Azret