Dynamic object property populator (without reflection)

Question

I want to populate an object\'s properties without using reflection in a manner similar to the DynamicBuilder on CodeProject. The CodeProject example is tailored for populat

Answer 1

Yeah,you can use code like this:

 for (int i = 0; i < dataRecord.FieldCount; i++)
                {

                    PropertyInfo propertyInfo = t.GetProperty(dataRecord.GetName(i));
                    LocalBuilder il_P = generator.DeclareLocal(typeof(PropertyInfo));

                    Label endIfLabel = generator.DefineLabel();

.... ...

Answer 2

Edit: all of this is basically what dapper does - but dapper is much more optimized. If I was writing this answer today, it would read simply: "use dapper".

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If you aren't hugely "up" on IL, there are alternatives that get you the speed of IL and the convenience of reflection.

First example:

HyperDescriptor - uses a custom PropertyDescriptor model that deals with the IL for you, so all you have is code like (plus the one-liner to enable HyperDescriptor):

public static IEnumerable<T> Read<T>(IDataReader reader) where T : class, new() 
{
    PropertyDescriptorCollection props =
        TypeDescriptor.GetProperties(typeof(T));

    PropertyDescriptor[] propArray = new PropertyDescriptor[reader.FieldCount];
    for (int i = 0; i < propArray.Length; i++)
    {
        propArray[i] = props[reader.GetName(i)];
    }
    while(reader.Read()) {
        T item = new T();
        for (int i = 0; i < propArray.Length; i++)
        {
            object value = reader.IsDBNull(i) ? null : reader[i];
            propArray[i].SetValue(item, value);
        }
        yield return item;
    }
}

Second example:

LINQ expressions - quite lengthy, but I've discussed this (and the above, it turns out) on usenet - see this archive.