Question

Let us say I have this code

string seachKeyword = "";
List<string> sl = new List<string>();
sl.Add("store");
sl.Add("State");
sl.Add("STAMP");
sl.Add("Crawl");
sl.Add("Crow");
List<string> searchResults = sl.FindAll(s => s.Contains(seachKeyword));

How can I ignore the letter case in Contains search?

Thanks,

Answer 1

The best option would be using the ordinal case-insensitive comparison, however the Contains method does not support it.

You can use the following to do this:

sl.FindAll(s => s.IndexOf(searchKeyword, StringComparison.OrdinalIgnoreCase) >= 0);

It would be better to wrap this in an extension method, such as:

public static bool Contains(this string target, string value, StringComparison comparison)
{
    return target.IndexOf(value, comparison) >= 0;
}

So you could use:

sl.FindAll(s => s.Contains(searchKeyword, StringComparison.OrdinalIgnoreCase));