How the Visual Studio debugger infer Value inside watch window?

Question

In the watch window for example I see:

Name : task
Value : Id = 11, Status = WaitingToRun, Method = "Void < RetreiveFromCache > b__0()"
Type : System.Threading.Tasks.Task

So the task variable is of Type Task and I want to access to the same Value the debugger prints, particularly I am interested in the Method value ( RetreiveFromCache )

However on the task variable I have only access to .Id, .Status, etc... but not .Method

Where does the Method value come from?

How can the debugger "infer" the Method value?

Answer 1

Yo can override the ToString() method. This is the easy way But what you are looking for are these classes:

• DebuggerDisplayAttribute
• DebuggerBrowsableAttribute

See https://msdn.microsoft.com/es-es/library/ms228992(v=vs.110).aspx for more information

Answer 2

The Action variable of the Task object is not accessible. What you can do, is create your own class that extends the functionality of Task , while exposing the Action (which holds the information about the method to run).

A quick example:

public class CustomTask : Task
{
    private Action m_action;

    public Action Action
    {
        get { return m_action; }
    }

    public CustomTask(Action action) : base(action)
    {
        m_action = action;
    }
}

Then in your code, you can use it like this:

CustomTask ct = new CustomTask(MyMethod);

Console.WriteLine("ID: {0}, Method: {1}, Status: {2}", ct.Id, ct.Action.Method, ct.Status);
//Prints: "ID: 1, Method: Void MyMethod(), Status: Created"

ct.Start();
Console.WriteLine("ID: {0}, Method: {1}, Status: {2}", ct.Id, ct.Action.Method, ct.Status);
//Prints: "ID: 1, Method: Void MyMethod(), Status: WaitingToRun"

ct.Wait();
Console.WriteLine("ID: {0}, Method: {1}, Status: {2}", ct.Id, ct.Action.Method, ct.Status);
//Prints: "ID: 1, Method: Void MyMethod(), Status: RanToCompletion"

Note that to access information about the method, you have to access ct.Action.Method .