. net extension methods

The extension method is actually adding an extension method to an existing type, which can be either an int, a string, a DateTime, or a custom type.

An extension class can be added with the premise that the extended class must be a static class.

In addition, the extension method must be a static method. So calling an extension method is called directly with the class name of the extension class.

For example, add an extension method to the String class: ToInt

public static Class Extendsstring

{

public static int ToInt (this string str)

{

int id;

Int. TryParse (t,out ID);

return ID;

}

}

As is visible from the above code, the extension method accepts a self parameter, this, type string, and this string must be placed at the first position of the method parameter.

. net extension methods