ReSharper 2017.2 Help

Transform Parameters refactoring

ReSharper | Refactor | Convert | Transform parameters…
ReSharper_TransformParameters

This refactoring helps you quickly change method signature by transforming parameters — e.g. get rid of out parameters, wrap parameters in a tuple or in a new class, etc. — and automatically update all usages of the method in your solution.

The refactoring lets you perform the following transformations:

  • Create a new class with public fields or auto-properties for types corresponding to the selected parameters, and use the newly created class instead of parameters.
  • Replace parameters with a tuple object.
  • For a method returning void, transform a selected out parameter to method return.
  • For a method returning void, wrap multiple selected out parameters to a tuple object and use it as method return.
  • For a method returning void, create a new class with public fields or auto-properties for types corresponding to the selected out parameters, and use the newly created class as method return.
  • For non-void methods with out parameters, combine out parameters with return type in a tuple object or in a newly created class.

The example below demonstrates a mix of transformations - we replace out parameter with method return, and we wrap two other parameters with a new class:

Before refactoringAfter refactoring
class TestClass { public void DrawCircle(Point ctr, float rad, out bool res) { // draw... res = true; } }
class TestClass { public bool DrawCircle(Circle circle) { // draw... . var res = true; return res; } } internal class Circle { public Circle(Point ctr, float rad) { Ctr = ctr; Rad = rad; } public Point Ctr { get; private set; } public float Rad { get; private set; } }

To transform method parameters

  1. Place the caret at the declaration or a usage of method in the editor, or select the method in the File Structure window. Or, alternatively set the caret at any of method parameters.
  2. Do one of the following:
    • Press Ctrl+Shift+R and then choose Transform Parameters
    • Right-click and choose Refactor | Transform Parameters in the context menu.
    • Choose ReSharper | Refactor | Convert | Transform parameters… in the main menu.
    The Transform Parameters dialog will open.
  3. Select parameters you want to transform.
  4. Depending on selected in/out parameters, ReSharper enables Method receives and/or Method returns selectors. Use these selectors to choose how in/out parameters should be transformed. If you choose to create a new class for parameters, you will be able to specify its name in a text box to the right of it.
  5. To apply the refactoring, click Next.
  6. If no conflicts are found, ReSharper performs the refactoring immediately. Otherwise, it prompts you to resolve conflicts.
ReSharper. Transforming method's parameters

This feature is supported in the following languages and technologies:

Language: C#
Language: VB.NET
Language: C++
Language: HTML
Language: ASP.NET
Language: Razor
Language: JavaScript
Language: TypeScript
Language: CSS
Language: XML
Language: XAML
Language: Resx
Language: Build Scripts
Language: Protobuf
Language: JSON
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The instructions and examples given here address the use of the feature in C#. For details specific to other languages, see corresponding topics in the ReSharper by Language section.

Last modified: 20 October 2017

See Also