combit List & Label 29 - .NET Help
combit.Reporting Namespace / ListLabel Class / Evaluate Event

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    Evaluate Event
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    The Designer function External$ allows offering of external functions in the List & Label formula assistant. Whenever the user uses this function, the Evaluate event is called, which evaluates the formula and returns the result or an error message. Usually it is preferable to use the DesignerFunction Class for custom functions.

    Public Event Evaluate As EvaluateHandler
    public event EvaluateHandler Evaluate
    event EvaluateHandler^ Evaluate
    Event Data

    The event handler receives an argument of type EvaluateEventArgs containing data related to this event. The following EvaluateEventArgs properties provide information specific to this event.


    Internal Callback data.


    User-defined parameters.


    Used for error description.


    Indicates whether the function is to be evaluated or checked only for syntax.


    Indicates that an error was encountered at the time of evaluation.


    Return value of the External$ function.

    private void LL_Evaluate(object sender, EvaluateEventArgs e)
         if(e.Contents == "greeting")
              e.NewValue = "Hello World";
              e.HasError = true;
              e.ErrorText = "You must enter \"greeting\".";

    Platforms: Windows 10 (Version 21H2 - 23H2), Windows 11 (21H2 - 22H2), Windows Server 2016 - 2022
    .NET: .NET Framework 4.8, .NET 6, .NET 7, .NET 8

    See Also