string array.Contains?

Question

.NET 2

string[] myStrings = GetMyStrings();    
string test = "testValue";

How can I verify if myStrings contains test?

Answer 1

In .NET 2.0, you could do the following if you want the index:

int index = Array.FindIndex(
    myStrings,
    delegate(string s) { return s.Equals(test); }
);

index will be -1 if myStrings does not contain test.

If you merely want to check for existence:

bool exists = Array.Exists(
    myStrings,
    delegate(string s) { return s.Equals(test); }
);

Answer 2

I have found an elegant answer at the page here http://www.dotnettoad.com/index.php?/archives/10-Array.Contains.html. What you have to do in .NET 2.0 is to cast to IList and call Contains method.

(IList<string> mystrings).Contains(test);

Answer 3

Here's a .NET 2.0 compliant approach. Using Array.Find will return null if the value isn't found.

C# Approach

string[] myStrings = { "A", "B", "testValue" };
string test = "testValue";
string result = Array.Find(myStrings, delegate(string s) { return s == test; });
Console.WriteLine("Result: " + result);

If you need a case insensitive match use s.Equals(test, StringComparison.InvariantCultureIgnoreCase).

EDIT: with VB.NET 2.0 more effort is required since it doesn't support anonymous delegates. Instead you would need to add a Function and use AddressOf to point to it. You would need to set the testValue as a member or property since it will not be passed in to the predicate method. In the following example I use Array.Exists.

VB.NET Approach

' field or property ' 
Dim test As String = "testValue"

Sub Main
    Dim myStrings As String() = { "A", "B", "testValue" }       
    Dim result As Boolean = Array.Exists(myStrings, AddressOf ContainsValue)
    Console.WriteLine(result)
End Sub

' Predicate method '
Private Function ContainsValue(s As String) As Boolean
    Return s = test
End Function