Debugging a .NET program using the framework library source

Source code debugging is another technique for .NET library debugging. Let's take a look at how you can use Visual Studio to step into Microsoft Source for the .NET library:

Microsoft actually maintains a number of servers that hold static files. These files are available based on the checksum. Once the symbols are loaded onto your machine, the reference server can be used to download the appropriate source file directly while you are debugging your application and press Step Into to a method that is defined in the .NET class library. As we already know, a program database (PDB) file holds all the information about line numbers, location, and even the checksum of the file. Visual Studio invokes a request to a file by sending this information available in the symbol files and downloads the appropriate file.

Let's start our sample application and place a breakpoint in the first line of the code. Now run the project until the breakpoint is hit. Open Call Stack, right-click on MSCorlib, and select Load Symbols. This will download the symbols of MScorlib, which will take a considerable amount of time. Once the symbols are downloaded, you can start debugging your application.

You can see that when the download is complete, the Call Stack frames turn dark because all the line numbers are now available. Now you can press F11 to step into the library code, say, for instance, Console.WriteLine.

You will be prompted with a license agreement when you choose Call Stack for the first time. You can even use Call Stack to move back and forth to different call statements.