如何使用EnvDTE获取类的using语句？

Question

I am working on a T4 template which produces partial classes based on existing partial classes.

Sometimes the generated code will reference types being used from the existing (non-generated) codebase.

The generated code must either fully qualify these types, or mimic the using statements it finds in the non-generated code.

Mimicking using statements seems better since it will support cases where the type is being referenced from a [Attribute(typeof(Something))] , where EnvDTE only returns the string literal "typeof(Something)" .

So: how do I find these using statements? I'm using tangible T4's AutomationHelper, but still can't seem to find a solution :(

Answer 1

You can get the using statements by looking at the FileCodeModel.CodeElements for the ProjectItem.

Each ProjectItem has a FileCodeModel property. The FileCodeModel.CodeElements will contain a CodeImport for each using statement. Note that the FileCodeModel.CodeElements will contain other things not just CodeImportss o you will need to check the type returned or filter the unwanted types.

An example is shown below. Here I am using the NuGet's Package Manager Console and PowerShell.

$p = Get-Project
$fileCodeModel = $p.ProjectItems.Item("Class1.cs").FileCodeModel
$fileCodeModel.CodeElements | % { $_.Namespace }

The code above assumes there is a Class1.cs file in the root of the project. For each using statement it will print the full namespace. Note that in the above code it is trying to print the Namespace for each CodeElement and some of the elements will not have this property so you will need to restrict this so it only looks at CodeImport types. The above will work for the following class file:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ClassLibrary1
{
    public class Class1
    {
    }
}

If you have using statements between the namespace ClassLibrary1 and the public class Class1 part you will need to do more work and look at the CodeNamespace members since the CodeImports will not be available directly from the FileCodeModel.CodeElements, but hopefully the above code should point you in the right direction.