Working around parameter as reference limitation

Question

Using C# 6.0

I need to copy the value of many properties (like 400 properties) from one object to another, however if the default value is the same then it is important that I don't copy it.

So I have code that looks like this

private void Set<T>(T to, T from)

{

if (EqualityComparer<T>.Default.Equals(to, from) == false) to = from;

}

However, since it is properties that I am passing, I can't pass the "to" by reference. I also can't just return the value, as I don't want to set the "to" value if it is the same as the "from" value.

I can't change the object itself, as I am using API for existing software, and the properties are part of the API.

A typical call to Set function currently looks like this

Set(oInvoice.Lines.ItemCode, oDelivery.Lines.ItemCode);

Any changes that could get me this limitation without having to write out for each line would be really appreciated.

Answer 1

@ZEKE ROSS, Welcome to Microsoft Q&A, if you want to copy value from one object to another object without having to write out for each line, I recommend that you could use reflection to do it.

Here is a code example you could refer to.

    internal class Program
    {
        static void Main(string[] args)
        {
            Example ex1 = new Example() { Name = "test1", Id = 1001, Address = "home" };
            Example ex2 = new Example() { Name = "test2", Id = 1001, Address = "home2" };
            Set<Example>(ex1, ex2);
        }
        private static void Set<T>(T to, T from)
        {
            var result1 = to.GetType().GetProperties().ToList();
            var result2 = from.GetType().GetProperties().ToList();
            for (int i = 0; i < result1.Count; i++)
            {
                if(result1[i].GetValue(to,null)!= result2[i].GetValue(from, null))
                {
                    result1[i].SetValue(to, result2[i].GetValue(from, null));
                }
            }
        }
 
    }
    public class Example
    {

        public string Name { get; set; }

        public int Id { get; set; }

        public string Address { get; set; }

    }

As the following result shown. the ex1's property's value all set to be the same as the ex2's property's value.

Hope my solution could be helpful for you.

Best Regards,

Jack

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