Is there any way to create property dynamically in c#?

Question

public class UserDetails
    {
        public string UserID { get; set; }

        public string UserName { get; set; }
    }

Here i want to add property dynamically. The type and property name would change dynamically, with those value i want to create property.

Check out dynamic: http://msdn.microsoft.com/en-us/library/dd264736.aspx — Bort, Feb 01 '13 at 11:34
And how you are going to use that property later? Without knowing it's type and name.. — Sergey Berezovskiy, Feb 01 '13 at 11:34
Yes, have a look here: http://stackoverflow.com/questions/6196022/adding-properties-dynamically-to-a-class — Artless, Feb 01 '13 at 11:35
http://stackoverflow.com/questions/6329489/dynamically-add-properties-to-a-existing-object — CloudyMarble, Feb 01 '13 at 11:36
What is going to be *consuming* this value? The answer to this matters. — Marc Gravell, Feb 01 '13 at 11:38

score 1 · Answer 1 · answered Feb 01 '13 at 12:10

This seems to work but requires casting to get to the "flexible" properties.

The UserDetails class

public class UserDetails
{
    private dynamic _internal;

    public static implicit operator System.Dynamic.ExpandoObject(UserDetails details)
    {
        return details._internal;
    }

    public UserDetails()
    {
        _internal = new System.Dynamic.ExpandoObject();
    }

    public string UserID 
    { 
        get
        {
            return _internal.UserID;
        }
        set
        {
            _internal.UserID = value;
        }
    }

    public string UserName
    { 
        get
        {
            return _internal.UserName;
        }
        set
        {
            _internal.UserName = value;
        }
    }
}

And using the class

UserDetails user = new UserDetails();
user.UserName = "bill";
user.UserID = "1";

dynamic dynamicUser = (System.Dynamic.ExpandoObject)user;
dynamicUser.newMember = "check this out!";

Console.WriteLine(user.UserName);
Console.WriteLine(user.UserID);
Console.WriteLine(dynamicUser.UserName);
Console.WriteLine(dynamicUser.UserID);
Console.WriteLine(dynamicUser.newMember);

score 0 · Answer 2 · answered Feb 01 '13 at 11:38

Yes, but it's complicated. Check out implementing ICustomTypeDescriptor. If you make your base class implement it, you will be able to add properties dynamically. There are tutorials on the web, search for the interface on the web.

The 2nd thing can be to use the ExpandoObject.
In this way you can not inherit from a base class, but it is much simpler to implement.

score 0 · Answer 3 · answered Feb 01 '13 at 11:57

It seems possible that all you really need is a "Property Bag", i.e. an unordered container into which you can insert name/value pairs where the name is a string and the value is any kind of object.

There are many implementations of PropertyBag available online; here's a quick and dirty one I threw together as an example:

using System;
using System.Collections;
using System.Collections.Generic;
using System.Drawing;

namespace Demo
{
    public static class Program
    {
        private static void Main(string[] args)
        {
            var properties = new PropertyBag();

            properties["Colour"]   = Color.Red;
            properties["π"]        = Math.PI;
            properties["UserId"]   = "My User ID";
            properties["UserName"] = "Matthew";

            // Enumerate all properties.

            foreach (var property in properties)
            {
                Console.WriteLine(property.Key + " = " + property.Value);
            }

            // Check if property exists:

            if (properties["UserName"] != null)
            {
                Console.WriteLine("[UserName] exists.");
            }

            // Get a property:

            double π = (double)properties["π"];
            Console.WriteLine("Pi = " + π);
        }
    }

    public sealed class PropertyBag: IEnumerable<KeyValuePair<string, object>>
    {
        public object this[string propertyName]
        {
            get
            {
                if (propertyName == null)
                {
                    throw new ArgumentNullException("propertyName");
                }

                if (_dict.ContainsKey(propertyName))
                {
                    return _dict[propertyName];
                }
                else
                {
                    return null;
                }
            }

            set
            {
                if (propertyName == null)
                {
                    throw new ArgumentNullException("propertyName");
                }

                _dict[propertyName] = value;
            }
        }

        public IEnumerator<KeyValuePair<string, object>> GetEnumerator()
        {
            return _dict.GetEnumerator();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

        private readonly Dictionary<string, object> _dict = new Dictionary<string, object>();
    }
}

Is there any way to create property dynamically in c#?

3 Answers3