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Project Items (Visual Studio SDK)

Custom tools let you associate a tool with an item in a project and run that tool whenever the file is saved. Certain custom tools, sometimes referred to as single-file generators, are frequently used to implement translators that generate code from data and vice versa. For example, single-file generators create Visual C# and Visual Basic source code out of the .settings and .resx files. The generated source code provides strongly-typed access to the data in the .settings and .resx files. The Visual C# and Visual Basic project types support custom tools; Visual C++ project types do not. Your own project types can also support custom tools.

Custom tools are registered components that implement the IVsSingleFileGenerator interface.

Custom tools are associated with a ProjectItem interface object, and are like designers and editors. A custom tool takes the file represented by a ProjectItem as input and writes a new file whose file name is provided by the DefaultExtension method.

Implementing Single-File Generators

Describes how to use the IVsSingleFileGenerator interface to implement a custom tool.

Determining the Default Namespace

Describes how to determine the correct namespace based on the language being used.

Registering Single File Generators

Provides descriptions for all the registry entries for a custom tool.

Exposing Types to Visual Designers

Explains how project systems provide support for visual designers to access generated classes and types through temporary portable executable (PE) files.

How to: Persist the Property of a Project Item

Shows how to persist a project item property, such as the author of a source file, in the project file.


Provides details about the IVsSingleFileGenerator, which transforms a single input file into a single output file that can be compiled or added to a project.


Explains the ProjectItem interface, which represents an item in a project.


Provides details about the DefaultExtension method, which retrieves the file name extension that is given to the output file name.

Projects and Solutions

Describes how to use Visual Studio projects and solutions to organize code files and resource files, and how to implement source control.