Please follow the below article:
In this code, you need to import System.Globalization, System.Resources namespaces and Create a CultureInfo that represents the specific culture which is specified with the specified name as shown below:
culture = CultureInfo.CreateSpecificCulture("ta-IN");
Here ta-IN represents tamil language of india
Create a ResourceManager object, it is a resource manager that provides access to culture specific resources at run time. The GetString method of the resource manager object returns the value of the string resource localized for the specific culture.
ResourceManager resman = new ResourceManager("WindowsFormsApp1.Resource.Res", typeof(Form1).Assembly);
Here WindowsFormsApp1 is the windows forms application name, Form1 is the form name. Mainform_text is the resource string in the resource file for that language(Tamil).
Microsoft Certified Technology Specialist in .Net