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T4 Output Directive

In Visual Studio text templates, the output directive is used to define the file name extension and encoding of the transformed file.

For example, if your Visual Studio project includes a template file named MyTemplate.tt which contains the following directive:

<#@output extension=".cs"#>

then Visual Studio will generate a file named MyTemplate.cs

The output directive is not required in a run-time (preprocessed) text template. Instead, your application obtains the generated string by calling TextTransform(). For more information, see Run-Time Text Generation with T4 Text Templates.

Using the Output Directive

<#@ output extension=".fileNameExtension" [encoding="encoding"] #>

There should be no more than one output directive in each text template.

extension attribute

Specifies the file name extension of the generated text output file.

The default value is .cs

  • Examples:
    <#@ output extension=".txt" #>

    <#@ output extension=".htm" #>

    <#@ output extension=".cs" #>

    <#@ output extension=".vb" #>

  • Acceptable Values:
    Any valid file name extension.

encoding attribute

Specifies the encoding to use when the output file is generated. For example:

<#@ output encoding="utf-8"#>

The default value is the encoding used by the text template file.

  • Acceptable Values:
    us-ascii

    utf-16BE

    utf-16

    utf-8

    utf-7

    utf-32

    0 (System default)

    In general, you can use the WebName string or the CodePage number of any of the encodings returned by Encoding.GetEncodings.