Case Sensitive Dictionary Keys
Solution 1
Dictionaries are case-sensitive by default - you don't need to do anything.
Dictionary<string, string> myDict = new Dictionary<string, string>();
myDict.Add("A", "value1");
myDict.Add("a", "value2");
See your code working online here: ideone.
If you are getting an error with your code then it's because one of those keys already exist in your dictionary.
Solution 2
All Dictionaries
are case-sensisitive. But you can use the case-insensitive string comparers provided by the StringComparer
class to create dictionaries with case-insensitive string keys.
Check it from ideone.
Solution 3
The OP is actually correct if he was using the StringDictionary Class. Microsoft's site states that the key is converted to lower-case before it's stored (https://msdn.microsoft.com/en-us/library/system.collections.specialized.stringdictionary(v=vs.110).aspx). To make the key case sensitive, using the Generic Dictionary as Mark Byers suggested works nicely. If you want a case insensitive key, StringDictionary works well.
spots
Full Stack Developer working at a large corporation. I currently do a lot of work with Oracle, .NET and Angular.
Updated on June 19, 2022Comments
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spots almost 2 years
I've found plenty of info on the web about making dictionaries able to do case insensitive look-ups such that if I added a key/value pair of ("A", "value") calling
MyDict["a"] == MyDict["A"]
will return true.
What I want to know is why I get a "key has already been added" error when I do
MyDict.Add("A", "value1"); MyDict.Add("a", "value2");
if I defined my dictionary to do case sensitive look-ups. Is there no way to define a Dictionary to be able to add different cased keys?
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spots over 11 yearsIt did already exist (means I need coffee), unfortunately I have to manually create a large dictionary with a ton of values and didn't account for the possibility of duplicates coming in. Thank you, also I've never seen ideone before so thank you for that too.
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Joshua K over 5 yearsI seem to be running into this. if I have a Dictionary<string,string> does it automatically make it a StringDictionary and just doesn't make it obvious for me?