Transform Parameters refactoring

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

tip

JetBrains Rider lets you change method signature in other ways (add, remove, rename, reorder parameters, change return type) with the Change Signature refactoring.

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.

note

In projects targeting .NET Framework 3.5 or lower this refactoring will not suggest transforming parameters or return method to tuple objects.

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:

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; }
}