Dictionary.ContainsKey(entry) returns false

Question

I have a string List that contains some numbers . I have some string in mybuylist that matches in Dictionary list. But this if condition always returns False. Ok mybuylist like [34,45,58] and mcollection(key,value) like this {[565,5]},{[34,1]},{[78,9]}....

public static Dictionary<string, int> mcollection = new Dictionary<string, int>();
public static List<string> mybuylist = new List<string>();

foreach (string entry in mybuylist) {

 if (mcollection.ContainsKey(entry))
    {
     //dosomething                     

    }

}

Hope someone help me about this

Obviously, `mcollection` has different keys than what's in `mylist`. — David S., Nov 16 '13 at 14:58
That means `mcollection` doesn't contain any keys as far as the [used string comparer](http://msdn.microsoft.com/en-us/library/ms132072(v=vs.110).aspx) is concerned. — GSerg, Nov 16 '13 at 15:01
sory for question is not clear. my list contains some dictionary keys but this always returns false — Erdem Alkan, Nov 16 '13 at 15:04
@ErdemAlkan The key words were *as far as the [used string comparer](http://msdn.microsoft.com/en-us/library/ms132072(v=vs.110).aspx) is concerned*. Are you expecting the strings to match case-insensitively? — GSerg, Nov 16 '13 at 15:08
@ErdemAlkan Why don't you show the contents of "mybuylist" and "mcollection" in your question so it would be clear enough ?? — T-D, Nov 16 '13 at 15:17
Ok mybuylist like [34,45,58] and mcollection key,value like this {[565,5]},{[34,1]},{[78,9]}.... — Erdem Alkan, Nov 16 '13 at 15:32
Your code working fine. where the issue is? See my Edit post. — Prasad Kanaparthi, Nov 16 '13 at 15:38

score 0 · Accepted Answer · edited May 23 '17 at 12:19

0

It might be the the problem of case-sensitive comparison or Keys are not matching. All Dictionaries are case-sensitive by default. A and a are different. Verify whether the values in mybuylist and mcollection are same or not.

Declare mcollection like below.

public static Dictionary<string, int> mcollection = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);

This will ignorecase and A & a are same.

See this.

EDIT 1:

class Program
{
    public static Dictionary<string, int> mcollection = new Dictionary<string, int>() { { "565", 5 }, { "34", 1 }, { "78", 9 } };
    public static List<string> mybuylist = new List<string>() { "34", "45", "58" };

    static void Main(string[] args)
    {
        foreach (string entry in mybuylist)
        {
            if (mcollection.ContainsKey(entry))
            {
                Console.WriteLine(entry);
                //dosomething                     
            }
        }
    }
}

O/P: 34

EDIT 2: Use below code to remove the spaces

mybuylist = mybuylist.ConvertAll(s => s.Trim());

edited May 23 '17 at 12:19

Community

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answered Nov 16 '13 at 15:14

Prasad Kanaparthi

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You don't know that is the reason. – Yosi Dahari Nov 16 '13 at 15:17
actualy all the items in mybuylist contains numeric chars. – Erdem Alkan Nov 16 '13 at 15:18
@Yosi what you mean? can you explain. – Prasad Kanaparthi Nov 16 '13 at 15:22
1

@PrasadKanaparthi - Sure, if you seen the contents of "mybuylist" and "mcollection" then you could realize if that's a problem of case-sensitive comparison, have you seen it? – Yosi Dahari Nov 16 '13 at 15:24
@ErdemAlkan update your question and give an example of an item that is contained in "mcollection" and also in "mybuylist" – T-D Nov 16 '13 at 15:24
i updated question with my list and dictionary values – Erdem Alkan Nov 16 '13 at 15:35
Yes i checked your code in different app you right yourr code runs perfect . But something wrong in my code. I initialized mybuylist with sql query that query returns string values. I also initialized my Dictionary list with parsing some text in my code. Both lists they have contains some strings matches. But if condition always return false. this makes me mad. – Erdem Alkan Nov 16 '13 at 16:00
1

Thank you. i found my mistake my sqlquery returns list items like "34 " i didnt realized there was a space char in list items. Gratz – Erdem Alkan Nov 16 '13 at 16:22
@ErdemAlkan, Please see my EDIT 2 response. – Prasad Kanaparthi Nov 16 '13 at 16:38
Thank you it also helped me. I am sory for the mess. – Erdem Alkan Nov 17 '13 at 10:32

Dictionary.ContainsKey(entry) returns false

1 Answers1