C# loop through array of objects

Question

I have an array that contains 2 elements and each element can contain one or more object with two properties: Id -> (string) and Names -> (List<string>).

You'll probably understand better by taking a look at the following image:

How can I loop through the elements of the second object and get the Id and Names properties for each of them?

This is how I've tried to implement it, but doesn't work:

foreach (var elem in classArray[1].GetType().GetProperties())
{
    var id = elem.Id;
    var name = elem.Names;
}

This is the Classification class:

public class Classification
{
    public string Id { get; set; }
    public List<string> Names { get; set; }
}

This is my code:

    List<object> classCollection = new List<object>();
    dynamic response = JsonConvert.DeserializeObject(result);
    for (int i = 0; i < response.Count; i++)
    {
        var classObj = response[i].element_classifications;
        var className = new List<string>();
        List<Classification> classList = new List<Classification>();

        for (int k = 0; k < classObj.Count; k++)
        {
            var classification = classObj[k].classifications;
            for (int j = 0; j < classification.Count; j++)
            {
                className.Add(classification[j].name.Value);
            }
            classList.Add(new Classification { Id = classObj[k].id.Value, Names = className });
        }
        classCollection.Add(classList);
    }
    var classArray = classCollection.ToArray();

Do you mean they can be any object, or they are always of type ExcelSDRAddIn.UserControlSDR.Classification? — littlerufe
– littlerufe, Commented Apr 6, 2017 at 19:51
Why are you using object[] then if the items are all of the same type? Using a strongly-typed collection will make life a lot easier. — D Stanley
– D Stanley, Commented Apr 6, 2017 at 20:07
I updated my question with my code ... It would help me a lot if you can tell me how to use a strongly-typed collection in my case. Thank you! — Valip
– Valip, Commented Apr 6, 2017 at 20:11

score 2 · Accepted Answer · 2017-04-06 20:04:11Z

2

You can cast the objects to the appropriate class:

foreach (var elem in ((IEnumerable)classArray[1]).Cast<ExcelSDRAddIn.UserControlSDR.Classification>())
{
    var id = elem.Id;
    var name = elem.Names;
}

edited Apr 6, 2017 at 20:04

answered Apr 6, 2017 at 19:54

user27414

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5 Comments

Valip Over a year ago

This returns me the following errors: cannot convert from 'object' to 'System.Linq.IQueryable' and

'object' does not contain a definition for 'Cast' and the best extension method overload 'System.Linq.Queryable.Cast<TResult>(System.Linq.IQueryable)' has some invalid arguments

user27414 Over a year ago

@Valip - you may need to also cast classArray[1], like so: ((IEnumerable)classArray[1]).Cast<ExcelSDRAddIn.UserControlSDR.Classification>()

Valip Over a year ago

It says that Using the generic type 'System.Collections.Generic.IEnumerable<T>' requires 1 type arguments

Valip Over a year ago

It works if I initialize classCollection as follows:

List<ExcelSDRAddIn.UserControlSDR.Classification[]> classCollection = new List<ExcelSDRAddIn.UserControlSDR.Classification[]>();

user27414 Over a year ago

You would cast it to System.Collections.IEnumerable, not System.Collections.Generic.IEnumerable<T>. But you figured it out so hurray!

Zinov · Accepted Answer · 2017-04-06 19:53:03Z

0

If the object is always the same

foreach(ExcelSDRAddIn.UserControlSDR.Classification variableName in classArray[i])

Or you can use dynamic or var

dynamic v = classArray[i].Id;
dynamic name = classArray[i].Names;

answered Apr 6, 2017 at 19:53

Zinov

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Comments

littlerufe · Accepted Answer · 2017-04-06 20:01:53Z

0

From your image, it looks like this would work:

foreach(var item in classArray[1])
{
    var typedItem = (ExcelSDRAddIn.UserControlSDR.Classification) item;

    Console.WriteLine($"Id {typedItem.Id} has names:");

    for (int i = 0; i < typedItem.Names.Count; i++)
    {
        Console.WriteLine($" - {typedItem.Names[i]}");
    }
}

edited Apr 6, 2017 at 20:01

answered Apr 6, 2017 at 19:57

littlerufe

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4 Comments

Valip Over a year ago

I've tried this too, but it returns

foreach statement cannot operate on variables of type 'object' because 'object' does not contain a public definition for 'GetEnumerator'

littlerufe Over a year ago

sorry, I missed that your array is of type object I updated my answer

littlerufe Over a year ago

@Valip is there some reason your array is not strongly typed to start with? Why is it not defined as: ExcelSDRAddIn.UserControlSDR.Classification[] classArray;

Valip Over a year ago

There is no reason my array is not strongly typed ... I just didn't know how to make it strongly typed. I updated the question with my code.

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