C# Dictionary Return Type

Question

I've got a problem with some c# code I'm writing, I'm fairly new to c# and I've had a look around and can't find a solution.

I've got a method that returns a Dictionary, I've set the return type to object and it seems ok.

    public object loopThroughNotificationCountQueries()
    {
        var countQuery = new Dictionary<string, string>(); ...


        ... return countQuery;
    }

The problem is in the main method where I'm trying to loop through the elements returned from the dictionary.

                Notification notification = new Notification();

                var countDictionary = notification.loopThroughNotificationCountQueries();


                foreach(KeyValuePair<String, String> entry in countDictionary)
                {
                    ...
                }

I'm getting an error saying "Error 2 foreach statement cannot operate on variables of type 'object' because 'object' does not contain a public definition for 'GetEnumerator'"

Is it because I'm not specifying the correct return type for a dictionary? Or is there another way of iterating through the entries in the returned object?

Thanks for your help, Stephen.

Solution 1

Look at your method declaration:

public object loopThroughNotificationCountQueries()

That means your countDictionary declaration is effectively:

object countDictionary = notification.loopThroughNotificationCountQueries();

... and you can't use foreach with an object like that. The simplest fix is to change the method declaration, e.g. to

// Note case change as well to follow .NET naming conventions
public IDictionary<string, string> LoopThroughNotificationCountQueries()

Solution 2

Use

public Dictionary<string, string> loopThroughNotificationCountQueries() { ... }

or explain why that's not possible.

Solution 3

public IDictionary<string, string> loopThroughNotificationCountQueries()
    {
        var countQuery = new Dictionary<string, string>(); ...


        ... return countQuery;
    }

Solution 4

Is there a reason you can't have your method signature as below? Do you always return a dictionary with a string key type and a string data type?

public Dictionary<string, string> loopThroughNotificationCountQueries() 

Solution 5

your loopThroughNotificationCountQueries returns object. Make it return Dictionary<string, string> by changing its signature.

public Dictionary<string, string> loopThroughNotificationCountQueries()
{
    var countQuery = new Dictionary<string, string>(); ...


    ... return countQuery;
}

View more solutions

Comments

[Oded]

He does specify a return type - object.

[Oded]

@Vlad - What access modifier? Do you mean return type?

[fixagon]

ha ha. like i write in the abstract of a book: "its a book" yes its correct

[Vlad]

@Oded Access Modifiers

[Oded]

If here were not to specify a return type, he would have used void.

[Oded]

@Vlad - I know what access modifiers are. I just don't understand why you think they are relevant to the answer.

[Ron Sijm]

public IDictionary would be better. (instead of Dictionary)

[Vlad]

@Oded Admittedly not very stackoverflowy of me, but I found Henk's typo amusing. The answer is valid too, so I stand by my +1.

[Oded]

@Vlad - Didn't spot the typo. Good thing I could see the edit ;)

[fixagon]

void would mean that the method declaration doesnt have a return type. but this one has one. its just not correct specified. ;-)

[user1035479]

Thanks for your help, as I said I'm new to C# and I wasn't aware that methods could be declared as a dictionary.