C#

using System.Runtime.InteropServices;

namespace PutYourNamespaceHere {
    /// <summary>
    /// Utility class for manipulating working set.
    /// </summary>
    internal class WorkingSet {
        /// <summary>
        /// Removes as many pages as possible from the working set of the
        /// current process.
        /// </summary>
        internal static void Empty() {
            SetProcessWorkingSetSize( -1, -1, -1 );
        }

        [ DllImport( "Kernel32", 
              CharSet=System.Runtime.InteropServices.CharSet.Auto, 
              SetLastError=true)]
        private static extern bool SetProcessWorkingSetSize(
            int handle, int min, int max);
    }
}

MyObject = new MyClass();

MyObject.SomeProperty = "XYZ";

//Start some thread passing my object instance

while(<here I need something to suspend this thread until
      the "SomeProperty"  of the class instance changes">);
{
     // Do some processing here
}