How to: Refactor Code with Extract Method

The following procedure describes how to create a new method from a code fragment of an existing member. Use this procedure to perform the Extract Method refactoring operation.

To use Extract Method

1. Create a console application.

   For more information, see Creating Console Applications (Visual C#).

2. In the Code Editor, select the code fragment you want to extract:

   double area = PI * radius * radius.
   

3. On the Refactor menu, click Extract Method.

   The Extract Method dialog box appears.

   Alternatively, you can also type the keyboard shortcut CTRL+R, M to display the Extract Method dialog box.

   You can also right-click the selected code, point to Refactor, and then click Extract Method to display the Extract Method dialog box.

4. Specify a name for the new method, such as CircleArea, in the New Method Name box.

   A preview of the new method signature displays under Preview Method Signature.

5. Click OK.

Example

To set up this example, create a console application named ExtractMethod, and then replace Program with the following code. For more information, see Creating Console Applications (Visual C#).

    class A
    {
        const double PI = 3.141592;

        double CalculatePaintNeeded(double paintPerUnit, double radius)
        {
            // Select any of the following:
            // 1. The entire next line of code.
            // 2. The right-hand side of the next line of code.
            // 3. Just "PI *" of the right-hand side of the next line
            //    of code (to see the prompt for selection expansion).
            // 4.  All code within the method body.
            // ...Then invoke Extract Method.

            double area = PI * radius * radius;

            return area / paintPerUnit;
        }
    }

See Also

Concepts

Refactoring

Reference

Extract Method