Analysis of if-statements for performance optimization

Does in c# all if statements were analysed before execution, so that in case an if statement can't be true (before proof all conditions) will be canceled?

My problem is, that i want to get rid of multiple if statements, becuase some methods in the if statement needs a long time to execute (which is wasted time if they were executed).

Here is a simple if statement (here it works). But how good is this on complex if statements?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;

namespace IfTest
{
    class Program
    {
        static void Main(string[] args)
        {
            if (true || NeedALongTime())
            {
                Console.WriteLine("!");
            }

            Console.ReadLine();
        }

        private static bool NeedALongTime()
        {
            Thread.Sleep(10000);

            return true;
        }
    }
}