Why is this an issue?
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)
{
// ...
}
