var proc = new Process
{
    StartInfo = new ProcessStartInfo
    {
        FileName = "cmd.exe",
        UseShellExecute = false,
        RedirectStandardOutput = true,
        RedirectStandardInput = true,
        CreateNoWindow = true
    }
};

proc.Start();
proc.StandardInput.WriteLine(delete
    ? "route delete " + ServiceIpAddress + " mask " + GatewayMask + " " + GatewayIpAddress + " -p" : "route add " + ServiceIpAddress + " mask " + GatewayMask + " " +  GatewayIpAddress + " -p");
roc.Close();