I'm running through Instructions as described in the course. I have created the site and when launching the site I get this error "Error Evaluating UI Expression Expression evaluation error in rule 'vfm_addvehicleform' at function a!dropdownField [line 18]: A null parameter has been passed." but I haven't created an expression rule 'vfm_addvehicleform', thus where should i look for this?. 'a!dropdownField [line 18]' I have also checked this in the contents interface and the line 18 is a boolean value. Thus I request to provide help to solve this.
The below is the code for form interface
=a!formLayout( label: "Add Vehicle to Fleet", instructions: "", contents: { a!columnsLayout( columns: { a!columnLayout( contents: { a!dropdownField( label: "Category", labelPosition: "ABOVE", placeholderLabel: "--- Select a category ---", choiceLabels: {"Small", "Economy", "Large", "Luxury"}, choiceValues: {"small", "Economy", "Large", "Luxury"}, value: ri!category, saveinto: ri!category, showwhen: true, required: true, validations: {} ), a!textField( label: "Make", labelPosition: "ABOVE", placeholder: "Make of the Vehicle", value: ri!Make, saveInto: ri!Make, refreshAfter: "UNFOCUS", required: true, validations: {} ), a!textField( label: "Model ", labelPosition: "ABOVE", placeholder: "Model of the Vehicle", value: ri!Model, saveInto: ri!Model, refreshAfter: "UNFOCUS", required: true, validations: { null } ), a!textField( label: "License Plate", labelPosition: "ABOVE", placeholder: "License plate no.", value: ri!VehicleLicensePlate, saveInto: ri!VehicleLicensePlate, refreshAfter: "UNFOCUS", required: ri!VehicleLicensePlate=7, validations: {} ), a!fileUploadField( label: "Picture", labelPosition: "ABOVE", target: cons!VFM_VEHICLES_IMAGES_FOLDER, value: ri!Image, saveInto: ri!Image, validations: {} ) } ), a!columnLayout( contents: { a!integerField( label: "Mileage", labelPosition: "ABOVE", placeholder: "Mileage of a Vehicle", value: ri!Mileage, saveInto: ri!Mileage, refreshAfter: "UNFOCUS", required: ri!Mileage> 100000, validations: {} ), a!paragraphField( label: "Condition", labelPosition: "ABOVE", placeholder: "Condition of the Vehicle", value: ri!VehicleCondition, saveInto: ri!VehicleCondition, refreshAfter: "UNFOCUS", required: true, height: "MEDIUM", validations: {} ) } ) } ) }, buttons: a!buttonLayout( primaryButtons: { a!buttonWidgetSubmit( label: "Submit", saveInto: {}, style: "PRIMARY" ) }, secondaryButtons: { a!buttonWidgetSubmit( label: "Cancel", value: true, saveInto: ri!cancel, style: "NORMAL", skipValidation: true ) } ), validations: {})
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The reason would have been that the rule input is of type CDT so when not populated, the dropdown has not recognised it as null (and therefore populated the value with the placeholder), but an empty CDT that is not a valid choiceValue.
To cater for this I would recommend choiceValues of a simple datatype.