CustomFunctions.Register(ICustomFunctionOperator[]) Method

Registers the specified custom functions in the Expression Editor in the End-User Report Designer.

Namespace: DevExpress.XtraReports.Expressions

Assembly: DevExpress.XtraReports.v20.2.dll

NuGet Packages: DevExpress.Reporting.Core, DevExpress.WindowsDesktop.Reporting.Core

Declaration

C#

public static void Register(
    params ICustomFunctionOperator[] functionOperators
)

VB.NET

Public Shared Sub Register(
    ParamArray functionOperators As ICustomFunctionOperator()
)

Parameters

Name	Type	Description
functionOperators	ICustomFunctionOperator[]	A collection of ICustomFunctionOperator objects specifying custom functions to register.

Remarks

The Register method registers a custom function in the Expression Editor to use for specifying control expression bindings and calculated fields expressions along with built-in functions.

You can declare a custom function by implementing an ICustomFunctionOperator interface that provides the base functionality. Implement an ICustomFunctionOperatorBrowsable interface if you want to specify additional function information such as a category, description or parameter count.

The following example demonstrates how to create a simple custom function and register it in the End-User Designer by calling the static Register method.

C#

using DevExpress.XtraReports.UI;
using DevExpress.XtraReports.Expressions;
// ...

public class MyCustomFunction : ICustomFunctionOperator {

    object ICustomFunctionOperator.Evaluate(params object[] operands) {
        // Insert your custom logic here.
        // For demonstration purposes, multiply an operand value to 10.
        return (Convert.ToDouble(operands[0]) * 10);
    }

    string ICustomFunctionOperator.Name {
        get { return "MyFunction"; }
    }

    Type ICustomFunctionOperator.ResultType(params Type[] operands) {
        return typeof(double);
    }
}

public Form1() {
    // ...
    CustomFunctions.Register(new MyCustomFunction());        
    reportDesigner1.OpenReport(new XtraReport());            
}

VB.NET

Imports DevExpress.XtraReports.UI
Imports DevExpress.XtraReports.Expressions
'...

Public Class MyCustomFunction
    Implements ICustomFunctionOperator

    Private Function Evaluate(ParamArray operands As Object()) As Object Implements ICustomFunctionOperator.Evaluate
        ' Insert your custom logic here.
        ' For demonstration purposes, multiply an operand value to 10.
        Return(Convert.ToDouble(operands(0)) * 10)
    End Function

    Private Property Name As String Implements ICustomFunctionOperator.Name
        Get
            Return "MyFunction"
        End Get
    End Property

    Private Function ResultType(ParamArray operands As Type()) As Type Implements ICustomFunctionOperator.ResultType
        Return GetType(Double)
    End Function
End Class

Public Sub Form1()
    '...
    CustomFunctions.Register(New MyCustomFunction())
    reportDesigner1.OpenReport(New XtraReport())
End Sub