As it seems to come up often enough I figured I'd throw together a quick snippet outlining basic methods for data manipulation in SQL Server using C#.
In all examples the coder will need to substitute their own connection string details and variables.
I utilised parameters for 3 of the examples but they can just as easily be replaced by direct references to dynamic controls in your application if desired. The benefit of parameters, however, is that they set the 'type' of the variable being passed and add an additional level of type checking to the app.
I'm hoping I didn't bugger any of the code samples when throwing them together.