Resource File Formats

Before we look into resource managers, let's take a brief look at the possibilities for resource file formats. Four resource file formats are used for resources. The .resx file format that you have already encountered is an XML format. The .resources format that you have also already encountered is a binary format representing a compiled .resx file. The .txt file format is simply a text file with key/value pairs. So Form1Resources.txt would simply be:

 InsufficientFunds=Insufficient funds for the transfer 

The .restext file format (introduced in the .NET Framework 2.0) is the same as the .txt file format; the only difference is the extension. The new extension enables developers to make a clearer distinction between a text file that might contain any freeform text and a text file that is used explicitly for resources. Table 3.1 compares the file formats.

Table 3.1. Resource File Formats

File Extension	Supports String Resources	Supports Other Resources	Supports Comments	Supports File References	Has Direct Support in the .NET Framework	Extension Recognized by ResGen
.resx	Yes	Yes	Yes	Yes	Yes	Yes
.resources	Yes	Yes	No	No	Yes	Yes
.txt	Yes	No	No	No	No	Yes
.restext	Yes	No	No	No	No	In 2.0 only

When choosing a file format, weigh the relative benefits of each. .resx files are recognized by Visual Studio and are human readable. They also have explicit classes for their manipulation (ResourceManager, ResXResourceReader, ResXResourceWriter). .resources files are not human readable and must originate from a .resx, .txt, or .restext file. .txt files are human readable but are not recognized as resource files by Visual Studio, and are not so easily manipulated programmatically as resources.