rspec/rules/S2692/csharp/rule.adoc

Most checks against an ``++IndexOf++`` value compare it with -1 because 0 is a valid index. Any checks which look for values ``++> 0++`` ignore the first element, which is likely a bug. If the intent is merely to check inclusion of a value in a ``++string++``, ``++List++``, or an array, consider using the ``++Contains++`` method instead.

This rule raises an issue when an ``++IndexOf++`` value retrieved from a ``++string++``, ``++List++`` or array is tested against ``++> 0++``.
This rule also raises an issue when ``++IndexOfAny++``, ``++LastIndexOf++`` or ``++LastIndexOfAny++`` from a ``++string++`` is tested against ``++> 0++``

== Noncompliant Code Example

----
string color = "blue";
string name = "ishmael";

List<string> strings = new List<string>();
strings.Add(color);
strings.Add(name);
string[] stringArray = strings.ToArray();

if (strings.IndexOf(color) > 0) // Noncompliant
{  
  // ...
}

if (name.IndexOf("ish") > 0) // Noncompliant
{ 
  // ...
}

if (name.IndexOf("ae") > 0) // Noncompliant
{ 
  // ...
}

if (Array.IndexOf(stringArray, color) > 0) // Noncompliant
{  
  // ...
}
----

== Compliant Solution

----
string color = "blue";
string name = "ishmael";

List<string> strings = new List<string> ();
strings.Add(color);
strings.Add(name);
string[] stringArray = strings.ToArray();

if (strings.IndexOf(color) > -1) 
{
  // ...
}

if (name.IndexOf("ish") >= 0) 
{
  // ...
}

if (name.Contains("ae"))
{
  // ...
}

if (Array.IndexOf(stringArray, color) >= 0)
{  
  // ...
}
----