using System;
using System.Collections.Generic;
using System.Reflection;
using System.Linq;

public class Test
{
	
	public void Delete<T>(T obj) where T : class {}
    public void Delete<T>(ICollection<T> obj) where T : class {}
	
	public static MethodInfo GetMethod(Type type) {
        var res = type
            .GetRuntimeMethods()
            .Where(x => x.Name.Equals("Delete"))
            .Select(m => new {Method = m, Parameters = m.GetParameters()})
            .FirstOrDefault(p =>
                p.Parameters.Length == 1
            &&  p.Parameters[0].ParameterType.IsGenericType
            &&  p.Parameters[0].ParameterType.GetGenericTypeDefinition() == typeof(ICollection<>)
            );
        return res != null ? res.Method : null;
    }
	
	public static void Main()
	{
		Console.WriteLine(GetMethod(typeof(Test)));
	}
}