Examples

C# classes:

[TypeScriptInterface]
public class MyModel
{
    public int Number { get; set; }
    public string Name { get; set; }
    public ReferencedModel Ref { get; set; }
}

[TypeScriptInterface]
public class ReferencedModel
{
    public double Fraction { get; set; }
    public int[] Digits { get; set; }
}

Resulting T4TS.d.ts:

module T4TS {
    export interface MyModel {
        Number: number;
        Name: string;
        Ref: ReferencedModel;
    }
    export interface ReferencedModel {
        Fraction: number;
        Digits: number[];
    }
}

This interface can now be used in your TypeScript files:

/// <reference path="T4TS.d.ts" />
class Test {
    constructor () {
        // Make an AJAX post and get some data from the server.
        // In the callback, you can specify that the data is of a certain type:
        $.post('./example', {}, (data: T4TS.MyModel) => {
            // Intellisense support for the properties:
            alert(data.Number.toString());
            alert(data.Ref.Digits[0].toString());
        });
    }
}