Resx files using a clean user interface, very much like Visual Studio does, hiding the complexity of the XML. I don't want users to be able to.

All files in a Visual Studio project have a build action. The build action controls what happens to the file when the project is compiled.


This topic applies to Visual Studio on Windows. For Visual Studio for Mac, see Build actions in Visual Studio for Mac.

Set a build action

To set the build action for a file, open the file's properties in the Properties window by selecting the file in Solution Explorer and pressing Alt+Enter. Or, right-click on the file in Solution Explorer and choose Properties. In the Properties window, under the Advanced section, use the drop-down list next to Build Action to set a build action for the file.

Build action values

Some of the more common build actions for C# and Visual Basic project files are:

Build ActionProject typesDescription
AdditionalFilesC#, Visual BasicA non-source text file that's passed to the C# or Visual Basic compiler as input. This build action is mainly used to provide inputs to analyzers that are referenced by a project to verify code quality. For more information, see Use additional files.
ApplicationDefinitionWPFThe file that defines your application. When you first create a project, this is App.xaml.
CodeAnalysisDictionary.NETA custom word dictionary, used by Code Analysis for spell checking. See How to: Customize the Code Analysis Dictionary
CompileanyThe file is passed to the compiler as a source file.
Content.NETA file marked as Content can be retrieved as a stream by calling Application.GetContentStream. For ASP.NET projects, these files are included as part of the site when it's deployed.
DesignDataWPFUsed for XAML ViewModel files, to enable user controls to be viewed at design time, with dummy types and sample data.
DesignDataWithDesignTimeCreateableWPFLike DesignData, but with actual types.
Embedded Resource.NETThe file is passed to the compiler as a resource to be embedded in the assembly. You can call System.Reflection.Assembly.GetManifestResourceStream to read the file from the assembly.
EntityDeploy.NETFor Entity Framework (EF) .edmx files that specify deployment of EF artifacts.
Fakes.NETUsed for the Microsoft Fakes testing framework. See Isolate code under test using Microsoft Fakes
NoneanyThe file isn't part of the build in any way. This value can be used for documentation files such as 'ReadMe' files, for example.
PageWPFCompile a XAML file to a binary .baml file for faster loading at run time.
ResourceWPFSpecifies to embed the file in an assembly manifest resource file with the extension .g.resources.
Shadow.NETUsed for an .accessor file that contains a list of built assembly filenames, one per line. For each assembly on the list, generate public classes with the names ClassName_Accessor that are just like the originals, but with public methods instead of private methods. Used for unit testing.
Splash ScreenWPFSpecifies an image file to be displayed at run time when the app is starting up.
XamlAppDefWindows Workflow FoundationInstructs the build to build a workflow XAML file into an assembly with an embedded workflow.


Additional build actions may be defined by for specific project types, so the list of build actions depends on the project type and values might appear that are not in this list.

See also

An resx file extension is associated with the Microsoft Visual Studio .NET development environment. An resx file contains XML resource template. Mac support for ntfs.

There is one other file type using
the RESX file extension!

.resx - Payroll Mate file

Software that open resx file

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RESX file extension- Microsoft Visual Studio .NET XML resource template

What is resx file? How to open resx files?

File type specification:

resx file icon:

The resx file extension is associated with Microsoft Visual Studio.

The resx files are used for developed application resource files or resource template files.
The RESX resource file format consists of XML entries, which specify objects and strings inside XML tags. One advantage of a RESX file is that when opened with a text editor (such as Notepad or Microsoft Word) it can be written to, parsed, and manipulated. When viewing a RESX file, you can actually see the binary form of an embedded object (a picture for example) when this binary information is a part of the resource manifest. Apart from this binary information, a RESX file is completely readable and maintainable.

The resx file contains a standard set of header information, which describes the format of the resource entries and specifies the versioning information for the XML used to parse the data.

The following example shows what a typical set of header statements in a resx file might look like.

Following the header information, each entry is described as a name/value pair, very similar to the way in which strings are specified in a txt file. A name/value pair in the .resx format is wrapped in XML code, which describes string or object values. When a string is added to a .resx file, the name of the string is embedded in a <data> tag, and the value is enclosed in a <value> tag, as in the following example.

When an object is inserted into a .resx file, the same <data> and <value> tags are used to describe the entry, but the <data> tag includes either a type or MIME type specifier. The type specifier holds the data type of the object being saved. The MIME type specifier holds the base type (Base64) of the binary information stored, if the object consists of binary data.

Updated: August 2, 2019

The default software associated to open resx file:


Company or developer:
Microsoft Corporation

Microsoft Visual Studio is an integrated development environment (IDE) used to create applications for Microsoft Windows, Windows Mobile, .NET Framework, Silverlight as well as dynamic websites and web applications. Visual Studio is available for Windows and Mac.

Help how to open:

Use any of the Microsoft Visual Studio suites. You can also view the *.resx files using text editor.

How to convert:

Probably cannot be converted to anything else.

Related links:

List of software applications associated to the .resx file extension

Recommended software programs are sorted by OS platform (Windows, macOS, Linux, iOS, Android etc.)
and possible program actions that can be done with the file: like open resx file, edit resx file, convert resx file, view resx file, play resx file etc. (if exist software for corresponding action in File-Extensions.org's database).

Click on the tab below to simply browse between the application actions, to quickly get a list of recommended software, which is able to perform the specified software action, such as opening, editing or converting resx files.

Software that open resx file - Microsoft Visual Studio .NET XML resource template

Programs supporting the exension resx on the main platforms Windows, Mac, Linux or mobile. Click on the link to get more information about listed programs for open resx file action.

Microsoft Windows:

NotePad++ text editor
Sublime Text
Microsoft Windows NotePad

Apple macOS / Mac OS X:


GNU Emacs
Sublime Text for Linux
Atom for Linux