Case-INsensitive Dictionary with string key-type in C#

This seemed related, but I didn't understand it properly: c# Dictionary: making the Key case-insensitive through declarations

It is indeed related. The solution is to tell the dictionary instance not to use the standard string compare method (which is case sensitive) but rather to use a case insensitive one. This is done using the appropriate constructor:

var dict = new Dictionary<string, YourClass>(
        StringComparer.InvariantCultureIgnoreCase);

The constructor expects an IEqualityComparer which tells the dictionary how to compare keys.

StringComparer.InvariantCultureIgnoreCase gives you an IEqualityComparer instance which compares strings in a case-insensitive manner.

var myDic = new Dictionary<string, string>(StringComparer.InvariantCultureIgnoreCase);
myDic.Add("HeLlo", "hi");

if (myDic.ContainsKey("hello"))
    Console.WriteLine(myDic["hello"]);

There are few chances where your deal with dictionary which is pulled from 3rd party or external dll. Using linq

YourDictionary.Any(i => i.KeyName.ToLower().Contains("yourstring")))