ASP.NET Web Forms support model binding and Value Providers are a part of the overall model binding feature. It grabs values from request and bind those values with method parameters. ASP.NET has inbuilt value providers and you can also create your own.
With this binding model, it is possible to have custom methods to perform select, insert, delete, and update operations. To create your own method, you need to create a class that implements IValue Provider interface.
Value Providers are classes that bind values from request to select method parameters. To learn more on how to use it, read the tutorial in this blog post: