C# in Depth

LINQ to SQL317■ I changed the type of the Severity, Status, and UserType properties to theirenum equivalents (having copied those enumerations into the project).■ I renamed the parent and child properties used for the associations betweenDefect and DefectUser—the designer guessed suitable names for the otherassociations, but had trouble here because there were two associations betweenthe same pair of tables.Figure 12.1 shows the designer diagram after all of these changes.As you can see, the model in figure 12.1 is exactly the same as the code modelshown in figure 11.3, except without the enumerations. The public interface is so similarthat we can create instances of our entities with the same sample data code. If youlook in the C# code generated by the designer (DefectModel.designer.cs), you’llfind five partial classes: one for each of the entities, and the DefectModelDataContextclass I mentioned earlier. The fact that they’re partial classes is important when itcomes to making the sample data creation code work seamlessly. I had created a constructorfor User, which took the name and user type as parameters. By creatinganother file containing a partial User class, we can add that constructor to our modelagain, as shown in listing 12.1.Figure 12.1 The LINQ to SQL classes designershowing the rearranged and modified entitiesLicensed to Rhona Hadida