.NET has two different user interface APIs. They are Windows Forms and WPF (Windows Presentation Foundation). Windows Forms is the original .NET user interface API and it stores most resource data including user interface data into .resx files. WPF is a new .NET user interface API that uses .xaml (XAML) files to stores user interface data and .resx files to store other data. The localized and compiled resource data in both cases are stored inside satellite assembly files. The process in both cases is similar: You select either original assembly file (.exe or .dll) or a Visual Studio project file (.csproj, .vbproj) or a Visual Studio solution file (.sln). Sisulizer scan the files and reads resource files/data and finally creates localized satellite assembly files.
Learn more about localization of APIs.
Here are some issues that are common in both Windows Forms and WPF localizations: