ref (C# reference)

You use the ref keyword in the following contexts:

• In a method signature and in a method call, to pass an argument to a method by reference.
• In a method signature, to return a value to the caller by reference. For more information, see ref return.
• In a declaration of a local variable, to declare a reference variable.
• As the part of a conditional ref expression or a ref assignment operator.
• In a struct declaration, to declare a ref struct. For more information, see the ref structure types article.
• In a ref struct definition, to declare a ref field. For more information, see the ref fields section of the ref structure types article.
• In a generic type declaration to specify that a type parameter allows ref struct types.