A C# array is modeled through a Modeler Type Definition.
To model a C# array in a model:
1. In the model, right-click the Model or Package that is to own the array, point to New, point to UML, point to Structure, point to Type Definition, and then click Array.
2. Type the name of the array.
3. Open the Type Definition's Property Pages, and then click the Options tab.
4. Click the Select button, and select the item to use as the type of the array.
5. In the Upper Bounds box, type the dimension of the array.