using System.Runtime.InteropServices; [DllImport("dnsapi.dll",EntryPoint="DnsFlushResolverCache")] private static extern UInt32 DnsFlushResolverCache (); public static void FlushMyCache() //This can be named whatever name you want and is the function you will call { UInt32 result = DnsFlushResolverCache(); } How To Implement this in Program.cs file Window Application. Can u please me in This :)