Using ValueInjecter, is there a way to only inject a given property one time - valueinjecter

Question

Given 3 classes,
A, and B which each have an ID property, and then various other properties
and C, which has an ID, and the combined properties of A and B,
I want to
C.InjectFrom(A);
C.InjectFrom(B);
such that the ID from A is preserved and not overwritten by B.
Obviously in this simple case, I could just reverse the order of the two calls, but in my real world example, it is slightly more complicated where I cannot just solve the problem with ordering.
Esentially I want the second injection to ignore anything that the first injection has already handled, and this may be continued down a chain of several injections. Some of these injections may be from the same objects too
C.InjectFrom(A);
C.InjectFrom<SomeInjector>(A);
C.InjectFrom<SomeInjector2>(A);
C.InjectFrom<SomeInjector3>(A);
etc.

Answer 1

here you go:
using System;
using System.Collections.Generic;
using Omu.ValueInjecter;
namespace ConsoleApplication2
{
class Program
{
static void Main(string[] args)
{
var a = new { Id = 1, P1 = "p1" };
var b = new { Id = 2, P2 = "p2" };
var c = new C();
var propList = new List<string>();
c.InjectFrom(new HandlePropOnce(propList), a);
c.InjectFrom(new HandlePropOnce(propList), b);
Console.WriteLine("Id = {0} P1 = {1} P2 = {2}", c.Id, c.P1, c.P2);
}
}
public class C
{
public int Id { get; set; }
public string P1 { get; set; }
public string P2 { get; set; }
}
public class HandlePropOnce : ConventionInjection
{
private readonly IList<string> handledProps;
public HandlePropOnce(IList<string> handledProps)
{
this.handledProps = handledProps;
}
protected override bool Match(ConventionInfo c)
{
if (handledProps.Contains(c.SourceProp.Name)) return false;
var isMatch = c.SourceProp.Name == c.TargetProp.Name && c.SourceProp.Type == c.TargetProp.Type;
if (isMatch) handledProps.Add(c.SourceProp.Name);
return isMatch;
}
}
}