Invoking a method designed to return a string representation of an object which is already a string is a waste of keystrokes. Similarly, explicitly
invoking ToString() when the compiler would do it implicitly is also needless code-bloat.
This rule raises an issue when ToString() is invoked:
- on a
string
- on a non-
string operand to concatenation
- on an argument to
string.Format
Noncompliant code example
var s = "foo";
var t = "fee fie foe " + s.ToString(); // Noncompliant
var someObject = new object();
var u = "" + someObject.ToString(); // Noncompliant
var v = string.Format("{0}", someObject.ToString()); // Noncompliant
Compliant solution
var s = "foo";
var t = "fee fie foe " + s;
var someObject = new object();
var u = "" + someObject;
var v = string.Format("{0}", someObject);
Exceptions
The rule does not report on value types, where leaving off the ToString() call would result in automatic boxing.
var v = string.Format("{0}", 1.ToString());
