https://learn.microsoft.com/pl-pl/dotnet/api/system.collections.specialized.collectionsutil.createcaseinsensitivehashtable?view=netframework-4.8.1
CollectionsUtil.CreateCaseInsensitiveHashtable Method (System.Collections.Specialized) | Microsoft...
Creates a new instance of the Hashtable class that ignores the case of strings.
methodsystemcollectionsspecializedmicrosoft