Look At T4 Templates In Visual Studio 2015 - Part Three

• Look At T4 Templates In Visual Studio 2015 - Part One
  
• Look At T4 Templates In Visual Studio 2015 - Part Two

In previous articles, we looked into class feature blocks and utility methods. Let’s drill down more and understand runtime\preprocessed templates and passing parameters to it. We can execute a preprocessed template via code, which will create a class and show the output of it. This can be executed outside of Visual Studio and no dependency on Microsoft.VisualStudio.Texttemplating.dll.

Let’s add a sample runtime template to our project and understand it:



Let’s add below code to output “runtime template” at execution:



Let’s look at generated code in Mytemplate.cs:



The code written in template will be called from TransformText() method and same will be executed at run-time via code. Here, our template inherited from MyTemplateBase and have a method TransformText() to process the template.

Let’s write below code in our console application to execute the template and see the results:



Output:



Here, we created an instance of our template and called TransformText() which will execute our template code and return the output.

Let’s extend our template by adding parameters to it:



We added two parameters to provide input to the template by using parameter directive,

(<#@ Parameter type=”System.Int32” Name=”Salary”) #>, for which values will be passed via code at run-time.

This will generate two read-only properties in MyTemplate.cs:



Let’s pass values to these parameters from console application by creating a session:



Here, we created a TextTemplating session to pass parameters than called Intialize() to transfer values and make it available in TransformText(). We need to add reference to Microsoft.VisualStudio.Textemplating.11.0.dll and Microsoft.VisualStudio.TextTemplating.Interface.11.0.dlls to create a session for parameter passing.

Output:



So, Runtime templates are helpful in generating code\documents on the fly, and can be executed outside of Visual Studio.

I am ending things here, in next article will drill down more on T4 Templates and look into reusing template and troubleshooting it. I hope this article will be helpful for all.

Read more articles on Visual Studio 2015: