| Declare Public numeric constants in a Visual Basic class module As you may know, Visual Basic doesn't allow public constants in a class module. This is really too bad, because often you'll find it necessary to declare constants that you can maintain and transfer along with the class, but that are also available to the projects that use the class. Well, the good news is that Visual Basic does provide a way to declare public constants in a class module. The bad news is that you can only do so with numeric constants. However, if that works for you, then consider including a Public Enum statement in your class. The Enum statement provides for enumeration of variables. Both variables and parameters can be declared with an Enum type. To use an Enum, you declare a type and fill it with elements. If you provide constant values for the elements, then Visual Basic uses those values. If you don't provide values, then Visual Basic starts the list at 0 and increments each element's value by one. For instance, with the following declaration: Public Enum POPConstants POP_CONNECT POP_USER POP_PASS POP_STAT POP_LIST POP_RETRIEVE POP_DELETE POP_QUIT End Enum POP_CONNECT would be equal to 0, POP_USER 1, POP_PASS 2, and so on. However, using the following declaration: Public Enum POPConstants POP_CONNECT = 2000 POP_USER = 3 POP_PASS = 10 POP_STAT = 4.5 POP_LIST = 7 POP_RETRIEVE POP_DELETE POP_QUIT End Enum the constants would equal the indicated values. Those constants without a value would be one more than the previous variable. So, since POP_LIST equals 7, POP_RETRIEVE woule be 8. You can use public Enum constants just as you would any other constants, like so: Private Sub Command1_Click() MsgBox POP_CONNECT & " " & POP_USER End Sub There's no need even to instantiate the class, since technically Visual Basic doesn't consider Public Enum as members of a class, even though they're written to the type library. |
Declare Public numeric constants in a Visual Basic |
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