Support for T4ParameterValues

[ltrzesniewski]

Would it be possible to get external parameter values using T4ParameterValues items and <#@ parameter #> directives? I'm looking to get a value from a MSBuild property.

Maybe I'm wrong, but as far as I can tell, properties are generated for declared parameters, but they're always null.

If I want to declare a RefAsmPath parameter, the generated Initialize method looks like this (decompiled):

public virtual void Initialize()
{
	if (((TextTransformation)this).Errors.HasErrors)
		return;
	bool RefAsmPathValueAcquired = false;
	if (((TextTransformation)this).Session.ContainsKey("RefAsmPath"))
	{
		_RefAsmPathField = (string)((TextTransformation)this).Session["RefAsmPath"];
		RefAsmPathValueAcquired = true;
	}
	if (!RefAsmPathValueAcquired)
	{
		string parameterValue = Host.ResolveParameterValue("Property", "PropertyDirectiveProcessor", "RefAsmPath");
		if (!string.IsNullOrEmpty(parameterValue))
		{
			TypeConverter tc = TypeDescriptor.GetConverter(typeof(string));
			if (tc != null && tc.CanConvertFrom(typeof(string)))
			{
				_RefAsmPathField = (string)tc.ConvertFrom(parameterValue);
				RefAsmPathValueAcquired = true;
			}
			else
				((TextTransformation)this).Error("The type 'System.String' of the parameter 'RefAsmPath' did not match the type of the data passed to the template.");
		}
	}
	if (!RefAsmPathValueAcquired)
	{
		object data = CallContext.LogicalGetData("RefAsmPath");
		if (data != null)
			_RefAsmPathField = (string)data;
	}
}

Except...

• Initialize is never called
• Session is null, so Initialize would throw anyway
• Host.ResolveParameterValue always returns string.Empty
• CallContext.LogicalGetData("RefAsmPath") returns null...

So I guess there's a lot to do in order to add support 😬