C# String.Contains Case Insensitive Extension Method

public static bool ContainsCaseInsensitive(this string source, string value)

{

int results = source.IndexOf(value, StringComparison.CurrentCultureIgnoreCase);

return results == –1 ? false : true;

}

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Tim Clark

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9 thoughts on “C# String.Contains Case Insensitive Extension Method”

  3. Even shorter and more flexible:
    public static bool Contains(this String item, String subString, StringComparison comparison)
    {
    return item.IndexOf(item, comparison) != -1;
    }

    //Ooops, previous was wrong;)

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  4. Even shorter and more flexible:
    public static bool Contains(this String item, String subString, StringComparison comparison)
    {
    return item.IndexOf(item, comparison) == -1;
    }

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  6. Hey Sectoid, whats up with the extra parameter “String subString” its not being used within the method logic? Let us know we are curious.

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  7. Way to get all the examples in the comments wrong guys.

    It shoud be != -1, and subString should be used instead of item as the first parameter of IndexOf

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  8. Best of both worlds (flexibility and terse syntax)

    public static bool Contains(this string source, string value, StringComparison comparisonType)
    {
    return source.IndexOf(value, comparisonType) != -1;
    }

    public static bool Contains(this string source, string value, bool ignoreCase)
    {
    return ignoreCase ? source.Contains(value, StringComparison.InvariantCultureIgnoreCase) : source.Contains(value, StringComparison.InvariantCulture);
    }

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