CustomFunctions Class

Enables you to register custom functions in the End-User Report Designer‘s Expression Editor.

Namespace: DevExpress.XtraReports.Expressions

Assembly: DevExpress.XtraReports.v18.2.dll

Declaration

C#

public static class CustomFunctions

VB.NET

Public Module CustomFunctions

Remarks

The CustomFunctions class allows you to register custom functions 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.

After creating a custom function, register it in the End-User Report Designer by calling the static CustomFunctions.Register method with the corresponding class instance passed as a parameter.

To unregister a specific function, use the static CustomFunctions.Unregister method.

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

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
    Inherits ICustomFunctionOperator

    Private Function Evaluate(ParamArray operands As Object()) As Object
        ' 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
        Get
            Return "MyFunction"
        End Get
    End Property

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

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

Inheritance

Object

CustomFunctions