Extension method to copy all instance parameters with same names/types from once class to another. First one is implementation second is usage.

gistfile1.cs

public static class MyExtensions {
  public static U CopyTo<U>(this Object obj){
		var objType = obj.GetType();
		var newType = typeof(U);
		var newInstance = Activator.CreateInstance<U>();
		
		var objProperties = objType.GetProperties(BindingFlags.Instance | BindingFlags.Public);
		var newProperties = newType.GetProperties(BindingFlags.Instance | BindingFlags.Public);
		
		foreach(var prop in objProperties){
			var value = prop.GetValue(obj);
			var newProp = newProperties.SingleOrDefault(x => x.Name == prop.Name && x.PropertyType == prop.PropertyType);
			if(newProp != null){
				newProp.SetValue(newInstance,value,null);
			}
		}
		return newInstance;
	}
}

gistfile2.txt

public class ParentClass{
	public int Number {get;set;}
	public string Text {get;set;}
}

public class ChildClass : ParentClass{
	public decimal AnotherNumber {get;set;}
	public string MoreText {get;set;}
}

void Main()
{
  var parent = new ParentClass{
  	Number = 4,
		Text = "SOME TEXT"
	};
	
	var child = parent.CopyTo<ChildClass>();
}