T4 templates error: loading the include file ef.utility.cs.ttinclude returned a null or empty string

问题

I have overridden the controller generation T4 templates (ControllerWithContext.tt) as described here.
I would like to take advantage of the code helper utilities found in EF.utility.CS.ttinclude as used in the POCO model generator T4 template. Therefore I copied the following lines from my Model.tt to my ControllerWithContext.tt.

<#@ include file="EF.Utility.CS.ttinclude"#>

However, when I try to add a controller I am getting the error message

Loading the include file 'EF.utility.CS.ttinclude' returned a null or empty string

According to the MSDN documentation, this error is because the included file is blank, which it clearly isn't because it works with Model.tt

The only difference I can see is that the overridden ControllerWithContext.tt does not have a Custom Tool defined, whereas the Model.tt has it set to TextTemplatingFileGenerator.

My workaround is to copy the functions I need from ef.utility.cs.ttinclude into my ControllerWithContext.tt, which in itself threw up more errors but which were easily solved.

How can I include T4 templates without a custom tool defined?

回答1:

Following @DustinDavis' advice, and using the invaluable information found on OlegSych's site, here's what I did:

Created a new project called CodeGenerationTools.
Added project references to
- System.Data.Entity.Design
- EnvDTE
- System.Data.Entity
- Microsoft.VisualStudio.TextTemplating.10.0
For this last reference I had to install the correct version of the Visual Studio SDK
Copied the EF.Utility.CS.ttinclude file into the project.
Renamed it CodeGenerationTools.cs
Edited the file and convert all <#@ import namespace="<name>" #> to using <name>;
Deleted the opening and closing <#+ #>
Added the directive using Microsoft.VisualStudio.TextTemplating;

Extended the class:

public class CodeGenerationTools : TextTransformation

Override the TransformText method

public override string TransformText() {
    throw new NotImplementedException();
}

Added empty constructor

public CodeGenerationTools() {
    _textTransformation = DynamicTextTransformation.Create(this);
    _code = new CSharpCodeProvider();
    _ef = new MetadataTools(_textTransformation);
    FullyQualifySystemTypes = false;
    CamelCaseFields = true;
}

Finally, build this project.

The next steps took place in the main project - Edited the T4 template file. - Changed template directive to

    <#@ template language="C#" HostSpecific="True" debug="false" inherits="CodeGenerationTools"#>

- Added the directives

    <#@ assembly name="C:\Visual Studio 2010\Projects\CodeGenerationTools\CodeGenerationTools\bin\Debug\CodeGenerationTools.dll" #>
    <#@ import namespace="CodeGenerationTools" #>

All of which now means I can use the helper methods found in EF.Utility.CS.ttinclude in my own T4 templates, and I have the means to add my own helper methods which will be available to all projects.

回答2:

If you have Visual Studio 2012 or 2013, install this EF tool to resolve the error.

回答3:

The answer is that the template processor isn't even trying to get the include file (as confirmed using ProcMon). You can reproduce this using any template, not just the EF.Utility.CS.ttinlcude

Not sure why you need the code but you can always build your own base class, just have it inherit from Microsoft.VisualStudio.TextTemplating.TextTransformation and then put in all the code thats is in the EF.Utility file. Then set the inherits directive to point to your new base class and then you can access those methods from your template.

来源：https://stackoverflow.com/questions/8078858/t4-templates-error-loading-the-include-file-ef-utility-cs-ttinclude-returned-a

标签

visual-studio-2010