Get fields from any class (based on type)

Question

I have a class Class1

public class Class1
{
    public string ABC { get; set; }
    public string DEF { get; set; }
    public string GHI { get; set; }
    public string JLK { get; set; }
}

How can I get a list of, in this case 'ABC', 'DEF', ... I want to get the name of all public fields.

I tried the following:

Dictionary<string, string> props = new Dictionary<string, string>();

foreach (var prop in classType.GetType().GetProperties().Where(x => x.CanWrite == true).ToList())
{
    //Console.WriteLine("{0}={1}", prop.Name, prop.GetValue(classitem, null));
    //objectItem.SetValue("ABC", "Test");
    props.Add(prop.Name, "");
}

And:

var bindingFlags = BindingFlags.Instance |
BindingFlags.NonPublic |
BindingFlags.Public;
var fieldValues = classType.GetType()
                            .GetFields(bindingFlags)
                            .Select(field => field.GetValue(classType))
                            .ToList();

But neither gave me the wanted results.

Thanks in advance

What, specifically, wasn't working about your attempted solutions? — Servy, Apr 01 '15 at 16:44
Take a look: [What is the difference between a Field and a Property in C#?](http://stackoverflow.com/questions/295104/what-is-the-difference-between-a-field-and-a-property-in-c) — Rubens Farias, Apr 01 '15 at 16:46
Classtype here defines, in this case "Class1", I want to make the same code work for multiple classes. What is not working that in none of both lists, I get the values that I want, which are "ABC", "DEF", ... — Dieter B, Apr 01 '15 at 16:49

score 1 · Accepted Answer · answered Apr 01 '15 at 16:48

1

Try something like this:

using System;
using System.Linq;

public class Class1
{
    public string ABC { get; set; }
    public string DEF { get; set; }
    public string GHI { get; set; }
    public string JLK { get; set; }
}

class Program
{
    static void Main()
    {
        // Do this if you know the type at compilation time
        var propertyNames 
            = typeof(Class1).GetProperties().Select(x => x.Name);

        // Do this if you have an instance of the type
        var instance = new Class1();
        var propertyNamesFromInstance 
            = instance.GetType().GetProperties().Select(x => x.Name);
    }
}

answered Apr 01 '15 at 16:48

Andrew Hare

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Clean and easy, Modified it to var instance = Activator.CreateInstance(classType); to make it work across several classes. – Dieter B Apr 01 '15 at 16:53
@Devcon2 will that only work for classes with a parameterless constructor? – Mike Apr 01 '15 at 17:10
@Mike: No, I used this for classes with overloaded constructors. – Dieter B Apr 01 '15 at 21:29

Rubens Farias · Answer 2 · 2015-04-01T17:02:47.820

Isn't clear what classType means in your original code.

If it's a instance of Class1 that should work; if you already got a System.Type, your classType.GetType() will not return your properties.

Also, you should be aware of properties and fields difference, as it matters to reflection. The code below lists your original properties, skips a property without setter and also a field, just to demonstrate how that conceptual difference affects your code.

class Program
{
    static void Main(string[] args)
    {
        var classType = typeof (Class1);
        foreach (var prop in classType.GetProperties().Where(p => p.CanWrite))
        {
            Console.WriteLine(prop.Name);
        }

        foreach (var field in classType.GetFields())
        {
            Console.WriteLine(field.Name);
        }
    }
}

public class Class1
{
    public string ABC { get; set; }
    public string DEF { get; set; }
    public string GHI { get; set; }
    public string JLK { get; set; }

    public string CantWrite { get { return ""; } }
    public string Field = "";
}

I didn't downvote, but an explanation is usually a good idea. — Heretic Monkey, Apr 01 '15 at 16:57

Get fields from any class (based on type)

2 Answers2