The Invalid Combo Box Widget error is issued in the following situations:

Edit this Combo Box widget and, depending on your requirements, define one of the following properties: Source Entity/Struct if you want to display all the rows of an entity or structure; Source Record List if you want to filter some of the entity rows to display; or Special List if you want to display generic values.

Edit this Combo Box widget and do one of the following operations: if you are using a special list for generic values, you have to use the Special Variable property to gather end-user input and, therefore, unset the Variable property. If you want to use entities or structures, set the Variable property accordingly with, respectively, the Identifier of the entity or the Source Identifier Attribute property.

Edit this Combo Box widget and set the Variable property to a variable whose data type is compatible with the data type of the Identifier of the entity.

Edit this Combo Box widget and set the Variable property with a variable whose data type is compatible with the data type of the Source Identifier Attribute property.

Edit this Combo Box widget and properly specify the Source Attribute property, i.e. if you are displaying the content of an entity, you have to select an entity attribute; if you are displaying the content of a structure, you have to select a structure attribute. This property is not mandatory if you are displaying generic values, through the Special List property.

Edit this Combo Box widget and specify the following properties: Source Entity/Struct and Source Attribute that indicate the attribute name displayed for each row of the entity.

Edit this Combo Box widget and specify the property Source Record List that contains the structure rows to be displayed in the widget.

Edit this Combo Box widget and specify the Source Identifier Attribute property as the structure attribute to be displayed.

Edit this Combo Box widget and change the Source Identifier Attribute property to a valid data type.

Edit the entity and define one of its attributes or a new attribute as an Identifier. How?

Clicking the symbol will take you directly to the widget mismatched property.

See Also

Combo Box Widget | About Error Messages