Using the Threads and Call Stack windows

When we want a thread-centric view of our application, the Threads window is the place to start. We can use the Threads window to see the location of all of our threads, see the thread call stack, and more. We can use the Call Stack window to view the stack frames of our application, or the function, or procedure calls that are currently on the stack.

In this recipe, we are going to see how to use the Threads and Call Stack windows in Visual Studio 2012 to view the call stack information for the threads in our application.

Getting ready…

Before we start looking at the debugging features of Visual Studio 2012, we need an application to debug. Let's create a Console application that spins up a few tasks so we can take a look at their call stack information.

  1. Start a new project using the C# Console Application project template and assign LockExample as the Solution name.
  2. Add the following using directives to the top of your Program class.
    using System;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;
  3. Let's start by creating a few static methods on the Program class. Add a method named Method1 that loops three times, creating tasks. The tasks just need to call Method2 with an integer parameter.
    static void Method1()
{
  Console.WriteLine("In Method1.");
  for (int i = 0; i < 3; i++)
  {
    Task.Factory.StartNew(index => Method2((int)index), i);               
  }
}
  4. Now create a method named Method2. Method2 just adds a random number to the parameter, writes the parameter to Console, and calls Method4.
    static void Method2(int number)
{
  Random rnd = new Random();
  var sum = number + rnd.Next(1,10);
  Console.WriteLine("In Method2. Value:{0}", sum);
  Method4(sum);            
}
  5. Next create Method3, which just starts a third task that calls Method2.
    static void Method3()
{
  Console.WriteLine("In Method3.");
  for (int i = 0; i < 3; i++)
  {
    Task.Factory.StartNew(() =>
    {
      Task.Factory.StartNew(index => Method2((int)index), i);
    });
    Thread.Sleep(10);
  }
  
}
  6. Lastly, create Method4 which contains our breakpoint.
    static void Method4(int number)
{
  Console.WriteLine("In Method4.", number);
  Debugger.Break();
}
  7. In the Main method, create a task that calls Method1 and Task that calls Method3. Wait for the user input before exiting.
    static void Main()
{
  var task1 = Task.Factory.StartNew(() => Method1());
  var task2 = Task.Factory.StartNew(() => Method3());
  Console.ReadLine();
}

How to do it…

Let's start a debugging session and take a look at the window.

  1. In Visual Studio 2012, press F5 to run the project.
  2. When the debugger hits the Debug.Break statement, go to the Debug menu of Visual Studio 2012, and click on Windows, and click on Call Stack to view the Threads window.
  3. The active thread is the thread that is currently selected in the Threads window, indicated by the arrow icon. By default, the active thread is the one that hits the breakpoint. Switch the active thread via the Threads window by double-clicking on a different thread in the view.
    How to do it…
  4. Go back to the Debug menu, click on Windows, and click on Threads to show the Call Stack window.
  5. The Call Stack window indicates the top of stack of the active thread with a arrow icon. This is known as the active stack frame. When switching threads, the active stack frame changes. When execution resumes, the execution continues from the active stack frame onwards.
    How to do it…
  6. The current stack frame is the stack frame that drives the rest of the debugger tools and windows. Change the current stack frame by double-clicking on a different entry in the Call Stack window. When changing the current stack frame to be something other than the active stack frame, it shows a tapered arrow.
    How to do it…
  7. You can navigate to the source code for any entry in stack frame. In the Call Stack window, right-click on the function whose source code you want to see and click on Go To Source Code from the shortcut menu.
    How to do it…
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