All other types (graphs, objects, ports, roles and relationships) have properties that specify what information can be attached to them. The Property Tool is a tool for creating and modifying these properties. The Property Tool can be opened by selecting Metamodel | Property Tool in the MetaEdit+ Launcher, by pressing the Property Tool button in the launcher toolbar, or by adding and viewing property definitions in other metamodeling tools.

Figure 2–16 shows a Property Tool. The structure of the window is similar to that in the Object Tool. The main difference between other tools and the Property Tool is that in place of a property list this tool has a Datatype pull-down list, which enables the selection of the type of the contents of the property. The data types are discussed in more detail in the next section. The Widget pull-down list is enabled only for string properties and defines how the string field will appear in property windows. With string and number data types you can enter a default value for the property in the Default Value field. In the Value Regex field you can enter a regular expression against which the property’s value will be matched. Non-matching values entered by modelers will be rejected and a warning about this will be shown. For more information about regular expressions in MetaEdit+, see Appendix A: Regular Expressions.

The Property Tool also has a Set Open Filter toolbar button that allows you to restrict type selection for the Open command to property types with a specific data type or widget. If no filter is given, the type selection list dialog shown by Open includes all property types.