Iterate Over A Collection in C#

I have the following classes created:

[Serializable]
public class AppContext : IXmlSerializable {
    public string reportType = string.Empty;
    public string entityId = string.Empty;

    // OPTIONS
    public IDictionary<string, OPTIONS> dict_Options = new Dictionary<string, OPTIONS>();
    // Advan开发者_开发技巧ced Options
    public List<string> listAdvancedOptions = new List<string>();



    public class OPTIONS {
        public string subjectId = string.Empty;
        public string varNumber = string.Empty;
    }
}

How do I iterate over the OPTIONS to get all the varNumbers?

---

Method 1

foreach (KeyValuePair<string, AppContext.OPTIONS> kvp in appContext.dict_Options)
{
  Console.WriteLine(kvp.Value.varNumber);
}

Method 2

foreach (AppContext.OPTIONS item in appContext.dict_Options.Values)
{
  Console.WriteLine(item.varNumber);
}

Method 3

foreach (string item in appContext.dict_Options.Select(x => x.Value.varNumber))
{
  Console.WriteLine(item);
}

---

A Dictionary<TKey, TVal> implements IEnumerable<KeyValuePair<TKey, TVal>>, so try this:

var varNumbers = dict_Options.Select(kvp=>kvp.Value.varNumber);

You can also access an IEnumerable of the values of the dictionary directly:

var varNumbers = dictOptions.Values.Select(v=>v.varNumber);

---

OPTIONS is a class that doesn't implement any collection interface (say IEnumerable). You can't iterate over it.

You can iterate over your dictionary - dict_Options:

foreach(var item in dict_Options)
{
  // use item - say item.varNumber
}

Note:

Having public fields in your class is bad design - it violates encapsulation and information hiding and will make it difficult to evolve the class. You should be using private fields and public properties to expose them.

---

If you just want to loop over all of the varNumbers I would probably do the following:

        var dict_Options = new Dictionary<string, OPTIONS>();

        foreach (var varNumber in dict_Options.Select(kvp => kvp.Value.varNumber))
        {
            // Your code.
        }