How to output namespace in T4 templates?

Question

I have a T4 template for a class set up with TextTemplatingFileGenerator Custom Tool in Visual Studio:

<#@ template language="C#v3.5" hostspecific="True" debug="True" #>
<#
  var className = System.IO.Path.GetFileNameWithoutExtension(Host.TemplateFile);
  var namespaceName = "MyNamespace";
#>

namespace <#= namespaceName #>
{
    public static class <#= className #>
    {
        // some generated code
    }
}

How can I get the value of the "Custom Tool Namespace" property in Visual Studio, so I don't have to hardcode the namespace?

I would even be happy with the default namespace for the C# project.

Answer 1

If you're using Visual Studio 2010, you can retrieve the namespace by checking the CallContext's "NamespaceHint" property.

System.Runtime.Remoting.Messaging.CallContext.LogicalGetData("NamespaceHint"); 

Answer 2

Here is what you can do with T4 Toolbox:

<#@ template language="C#v3.5" hostspecific="True" debug="True" #>  <#@ include file="T4Toolbox.tt" #> <#    var namespaceName = TransformationContext.DefaultNamespace;  #>  

DefaultNamespace property of TransformationContext class returns a string with namespace based on the root namespace of your project and the location of your .tt file in it (i.e. it treats folders as namespaces). This way you don't have to specify Custom Tool Namespace property for every instance of your .tt file.

If you prefer to use the Custom Tool Namespace property, you can pass Host.TemplateFile to the GetCustomToolNamespace method posted by @sixlettervariables.

Answer 3

Damien Guard includes some code in a blog posting which retrieves the Custom Tool Namespace for a given file:

public override String GetCustomToolNamespace(string fileName)
{
    return dte.Solution.FindProjectItem(fileName).Properties.Item("CustomToolNamespace").Value.ToString();
}

Answer 4

How I've done this:

<#@ assembly name="EnvDTE" #>
<#@ import namespace="EnvDTE" #>

<# 
    // Get value of 'Custom Tool Namespace'
    var serviceProvider = (IServiceProvider)this.Host;
    var dte = (DTE)serviceProvider.GetService(typeof(DTE));    
    var Namespace = dte.Solution.FindProjectItem(this.Host.TemplateFile).Properties.Item("CustomToolNamespace").Value;
 #>

namespace <#= Namespace #> {

}