LINQBridgeVs is a Visual Studio Extension compatible with Visual Studio 2012/2013/2015/2017. It is a bridge between a Visual Studio debugging session and LINQPad. It creates, at compile time, a Custom Debugger Visualizer making the magnifier glass available for all of the public classes and structs. By clicking on the magnifier glass on an object instance, this will be transmitted over a bus and 'Dumped' out by LINQPad.

Once the extension is installed, a new menu called "BridgeVs" will be available in the Visual Studio Menu Bar. Such menu is only visible when a solution is loaded. There are two options available:

• Bridge Solution
• Un-Bridge Solution

Bridging a solution will extend the MsBuild process to create a custom debugger visualizer assembly for each project. These assemblies are created or updated when you build your projects. Private and internal classes are not included, hence the magnifier glass will not be available for them.

Run the solution, set a breakpoint and hover the mouse pointer on any object instance then the magnifier glass will appear inside the data tip.

LINQBridgeVs is compatible with any Visual Studio edition from 2012 to 2017. It works only for .NET Framework 4.0 to 4.6.2. There is no support for .NET Framework 3.5 downwards. LINQPad 4 and 5 are both supported.

If after bridging and rebuilding your solution the magnifier glass still does not appear, make sure that in this folder "C:\Users\youruser\Documents\Visual Studio 201x\Visualizers" there is/are assemblies with this name template "AssemblyName.Visualizer.V1x.dll" (where x is the version number of Visual Studio). If the folder does not contain any assembly then please open a new bug.

Do not keep two instances of two different versions of LINQPad running (e.g. LINQPad 4 and LINQPad 5) at the same time. If you do so, the data will be automatically sent to the lower version of LINQPad.

Unfortunately an installer is not available yet, therefore Visual Studio needs to be configured in order to run the extension. This is done only once by the extension itself. Only for the first time, Visual Studio must be run with Administrator privileges. If not, a form will appear asking to restart Visual Studio:

Once Visual Studio is restarted as Administrator, the configuration will complete and the form will never appear again.

During this process two custom MsBuild Targets, Custom.After.Microsoft.Common.targets and Custom.Before.Microsoft.Common.targets, are needed to extend the MsBuild process. They are copied into a specific Visual Studio version and edition's folder:

• Visual Studio 2017 - C:\Program Files (x86)\Microsoft Visual Studio\2017{Edition}\MSBuild\v15.0
• Visual Studio 2015 - C:\Program Files (x86)\MSBuild\v14.0
• Visual Studio 2013 - C:\Program Files (x86)\MSBuild\v12.0
• Visual Studio 2012 - C:\Program Files (x86)\MSBuild\v4.0

You can skip this process but you will not be able to use the extension until you complete the configuration.

LINQBridgeVs uses a technique called Aspect Oriented Programming. AOP is a programming paradigm that aims to increase modularity, by allowing separations of cross-cutting concerns (read behaviors) without modifying the code itself. Usually this is achieved by adding an extra step into the build process after the assembly is created. Specifically, in Visual Studio the Build Engine is called MsBuild and it is to be extended to use AOP. This can be done by either copying a custom Target file to a specific MsBuild folder or by adding Target tags in a project file like the following:

<!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
       Other similar extension points exist, see Microsoft.Common.targets. -->
 <Target Name="BeforeBuild">
  </Target>
  <Target Name="AfterBuild">
  </Target>

This extension uses custom build Targets in order to avoid the modification of each individual project.

When a solution is Bridged, every project in is essentially flagged. Configuration values are stored in the Windows Registry at this location \HKEY_CURRENT_USER\Software\LINQBridgeVs

For each flagged project there are custom tasks that run before and after a project is built:

• Mapper Task - This task creates a Custom Debugger Visualizer assembly for each project.
• SInjection Task - SInjection stands for "Serializable Injection". This task reads the built assembly and marks every public class and struct as Serializable. It also ensures that any type is serializable using the BinaryFormatter.
• Clean Task - This task deletes the Custom Debugger Visualizer assemblies generated by the Mapper task.

From the MSDN documentation:

Visualizers are components of the Visual Studio debugger user interface. A visualizer creates a dialog box or another interface to display a variable or object in a manner that is appropriate to its data type. For example, an HTML visualizer interprets an HTML string and displays the result as it would appear in a browser window; a bitmap visualizer interprets a bitmap structure and displays the graphic it represents. The Visual Studio debugger includes six standard visualizers.

The process of creating custom visualizers to extend the debugger is not too complicated. However, it requires a lot of setup, either for mapping a class to custom visualizer but also to prepare the class for serialization.

The architecture of a debugger visualizer has two parts:

• The debugger side runs within the Visual Studio debugger.
• The debugger-side code creates and displays the user interface for your visualizer.

The debuggee side runs within the process Visual Studio is debugging (the debuggee). The debuggee side has to send that data object to the debugger side, which can then display it using a user interface you create. In order to send that data, the object needs to be serialized. Unless you use a serializer, like JSON.NET, that requires no markup on neither the class itself nor on the properties, the class must be marked as Serialized, or with other specific attributes depending on the serializer.

Below is an example of what it is needed to map a class to a custom debugger visualizer:

using DebuggerVisualizerExample;
using Microsoft.VisualStudio.DebuggerVisualizers;
using Microsoft.Windows.Form;

[assembly: System.Diagnostics.DebuggerVisualizer(
    typeof(DebuggerSide),
    typeof(VisualizerObjectSource),
    Target = typeof(Class1),
    Description = "My First Visualizer")]
[assembly: System.Diagnostics.DebuggerVisualizer(
    typeof(DebuggerSide),
    typeof(VisualizerObjectSource),
    Target = typeof(Class2),
    Description = "My First Visualizer")]
[assembly: System.Diagnostics.DebuggerVisualizer(
    typeof(DebuggerSide),
    typeof(VisualizerObjectSource),
    Target = typeof(Class3),
    Description = "My First Visualizer")]
namespace DebuggerVisualizerExample
{
    [Serializable]
    public class Class1 { }

    [Serializable]
    public class Class2 { }

    [Serializable]
    public class Class3 { }

    public class DebuggerSide : DialogDebuggerVisualizer
    {
        protected override void Show(IDialogVisualizerService windowService, IVisualizerObjectProvider objectProvider)
        {
            MessageBox.Show(objectProvider.GetObject()); //obviously MessageBox can't show any object we pass to it
        }
    }
}

For each class (Class1, Class2, Class3) a global assembly attribute that maps the type to a debugger visualizer is needed. This extension does all of this automatically. Internally it uses the .NET BinaryFormatter to send the data from the debuggee to the debugger. If the BinaryFormatter fails to serialize the data, JSON.NET is used instead.

I have used several community open source projects to make this extension. So if you like LINQBridgeVs I recommend checking out the following:

• LINQPad super useful scratch pad for C#, VB, F# and SQL. Without it this extension would not exist.
• Mono.Cecil very famous and useful AOP library designed, written and maintaned by JB Evain to generate and inspect programs and libraries in the ECMA CIL format.
• JSON.NET is an awesome serializer. It has become part of the .NET Framework and it is used by millions worlwide, now it has become the standard. LINQBridgeVs mainly uses the BinaryFormatter, but should it fail, it uses JSON.NET as a fallback mechanism.
• VsRestart is an extension that restart Visual Studio under Administrator privileges. Unfortunately the project seems abandoned. The extension works only with Visual Studio 2013. However, code proved to be working with any Visual Studio version.
• MahApps which was the first open source project to make WPF truly modern.
• ILMerge is a utility that merges multiple .NET assemblies into a single assembly.