best way to project ViewModel back into Model

Question

Consider having ViewModel :

public class ViewModel
{
    public int id {get;set;}
    public int a {get;set;}
    public int b {get;set;}
}

Answer 1

For this purpose we have written a simple mapper. It maps by name and ignores virtual properties (so it works with entity framework). If you want to ignore certain properties add a PropertyCopyIgnoreAttribute.

Usage:

PropertyCopy.Copy(vm, dbmodel);
PropertyCopy.Copy(dbmodel, vm);

Code:

public static class PropertyCopy
{
    public static void Copy(TDest destination, TSource source)
        where TSource : class
        where TDest : class
    {
        var destProperties = destination.GetType().GetProperties()
            .Where(x => !x.CustomAttributes.Any(y => y.AttributeType.Name == PropertyCopyIgnoreAttribute.Name) && x.CanRead && x.CanWrite && !x.GetGetMethod().IsVirtual);
        var sourceProperties = source.GetType().GetProperties()
            .Where(x => !x.CustomAttributes.Any(y => y.AttributeType.Name == PropertyCopyIgnoreAttribute.Name) && x.CanRead && x.CanWrite && !x.GetGetMethod().IsVirtual);
        var copyProperties = sourceProperties.Join(destProperties, x => x.Name, y => y.Name, (x, y) => x);
        foreach (var sourceProperty in copyProperties)
        {
            var prop = destProperties.FirstOrDefault(x => x.Name == sourceProperty.Name);
            prop.SetValue(destination, sourceProperty.GetValue(source));
        }
    }
}