Let's start with defining our client-side interfaces to handle questions, answers, and results; from Solution Explorer, right-click on the /ClientApp/app/interfaces/ folder and create the TypeScript files with the appropriate names and contents described here:

• question.ts: Here's the code for the question.ts file:

interface Question {
    Id: number;
    QuizId: number;
    Text: string;
}

• answer.ts: Here's the answer.ts file:

interface Answer {
    Id: number;
    QuestionId: number;
    Text: string;
    Value: number;
}

• result.ts: Here's the result.ts file:

interface Result {
    Id: number;
    QuizId: number;
    Text: string;
    MinValue?: number;
    MaxValue?: number;
}

Note how we also included the foreign-key properties to retrieve the Quiz or Question parent, as we'll use them in our client app soon enough.