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Select the Visual Basic language version

  • บทความ

The Visual Basic compiler defaults to the latest major version of the language that has been released. You may choose to compile any project using a new point release of the language. Choosing a newer version of the language enables your project to make use of the latest language features. In other scenarios, you may need to validate that a project compiles cleanly when using an older version of the language.

This capability decouples the decision to install new versions of the SDK and tools in your development environment from the decision to incorporate new language features in a project. You can install the latest SDK and tools on your build machine. Each project can be configured to use a specific version of the language for its build.

There are three ways to set the language version:

Edit the vbproj file

You can set the language version in your .vbproj file. Add the following element:

<PropertyGroup>
   <LangVersion>latest</LangVersion>
</PropertyGroup>

The value latest uses the latest minor version of the Visual Basic language. Valid values are:

Value Meaning
default The compiler accepts all valid language syntax from the latest major version that it can support.
9 The compiler accepts only syntax that is included in Visual Basic 9.0 or lower.
10 The compiler accepts only syntax that is included in Visual Basic 10.0 or lower.
11 The compiler accepts only syntax that is included in Visual Basic 11.0 or lower.
12 The compiler accepts only syntax that is included in Visual Basic 12.0 or lower.
14 The compiler accepts only syntax that is included in Visual Basic 14.0 or lower.
15 The compiler accepts only syntax that is included in Visual Basic 15.0 or lower.
15.3 The compiler accepts only syntax that is included in Visual Basic 15.3 or lower.
15.5 The compiler accepts only syntax that is included in Visual Basic 15.5 or lower.
16 The compiler accepts only syntax that is included in Visual Basic 16 or lower.
16.9 The compiler accepts only syntax that is included in Visual Basic 16.9 or lower.
latest The compiler accepts all valid language syntax that it can support.

The special strings default and latest resolve to the latest major and minor language versions installed on the build machine, respectively.

Configure multiple projects

You can create a Directory.build.props file that contains the <LangVersion> element to configure multiple directories. You typically do that in your solution directory. Add the following to a Directory.build.props file in your solution directory:

<Project>
 <PropertyGroup>
   <LangVersion>15.5</LangVersion>
 </PropertyGroup>
</Project>

Now, builds in every subdirectory of the directory containing that file will use Visual Basic version 15.5 syntax. For more information, see the article on Customize your build.

Set the langversion compiler option

You can use the -langversion command-line option. For more information, see the article on the -langversion compiler option. You can see a list of the valid values by typing vbc -langversion:? .