.NET Resources file (.resx)

.NET Resources (.resx) is a file format commonly utilized by .NET applications for storing localizable resources. It is an XML-based file format that comes with a pre-defined syntax for keeping resources organized and easy to access. The .resx files are monolingual, meaning that each file is designated to hold resources for a single language.

RESX file example

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<root>
    <resheader name="resmimetype">
        <value>text/microsoft-resx</value>
    </resheader>
    <resheader name="version">
        <value>2.0</value>
    </resheader>
    <resheader name="reader">
        <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
    </resheader>
    <resheader name="writer">
        <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
    </resheader>
    <data name="CommonBack">
        <value>&lt; Back</value>
    </data>
    <data name="CommonNext">
        <value>Next &gt;</value>
    </data>
    <data name="PageHomeIntro">
        <value>Welcome to our website,
where technology and innovation meet creativity and design.</value>
        <comment>Multiline intro message</comment>
    </data>
    <data name="PageHomeSubtitle">
        <value>Welcome, {0} {1}!</value>
        <comment>Welcome message that includes the user's first and last name.</comment>
    </data>
    <data name="PageHomeTitle">
        <value>Home</value>
    </data>
</root>

Placeholder

Placeholders in .resx files are represented by curly braces {} and are used to show dynamic content in localized messages. For example, the message below shown uses placeholders {0} and {1} to represent the order number and shipping address, respectively. At runtime, these placeholders are replaced with actual values to create a customized message.

<data name="OrderNotification">
    <value>Your order ("{0}") has been shipped and is on its way to "{1}"</value>
</data>

Comment

Comments in .resx files can be useful for explaining the purpose of a resource, providing context or additional information, or even serving as a reminder for future updates.

<data name="PageHomeTitle">
    <value>Home</value>
    <comment>Home page title. The maximum allowed length is 10 characters.</comment>
</data>

What are the most frequent errors in .resx files?

The most frequent errors in .resx files typically include missing or incorrectly formatted elements, incorrect values for attributes, and failure to properly escape special characters. Other common errors include file corruption or encoding issues, as well as incorrect naming conventions or mismatches between file and code.

What characters need to be escaped in .resx files?

Certain characters such as ampersands (&), less-than signs (<), and greater-than signs (>) need to be escaped in .resx files to prevent issues with parsing and interpretation.