Professional Visual Studio® 2008

43.2. Type Proxies

So far, you have seen how you can modify the tooltip to show information that is more relevant to debugging your application. However, the attributes discussed so far have been limited in how they control what information is presented in the expanded tree. The DebuggerBrowsable attribute enables you to hide particular members, but there is no way to add more fields. This is where the DebuggerTypeProxy attribute can be used to provide you with complete control over the layout of the tooltip.

The other scenario where a type proxy is useful is where a property of a class changes values within the class. For example, the following snippet from the Customer class tracks the number of times the OrderCount property has been accessed. Whenever the tooltip is accessed, the CountAccessed property is incremented by one:

public class Customer
{
    private int m_CountAccessed;
    public int OrderCount
    {
        get
        {
            m_CountAccessed++;
            return this.Orders.Count;
        }
    }

    public int CountAccessed
    {
        get
        {
            return this.m_CountAccessed;
        }
    }
}

Figure 43-6 illustrates the tooltip you want to be shown for the Customer class. Instead of showing the full list of orders to navigate through, it provides a summary about the number of orders, the maximum and minimum order quantities, and a list of the items on order.

Figure 43.6. Figure 43-6

The first line in the tooltip is the same as what you created ...