We can start and stop a service programmatically using C#. Basically, we need a service name and service startup type that we have to provide to start or stop. Here i will give an example to start a service.

private void StartService()
{
System.ServiceProcess.ServiceController[] allService = System.ServiceProcess.ServiceController.GetServices();
  foreach (System.ServiceProcess.ServiceController s in allService)
 {
if (s.ServiceName.Equals("Alerter"))
  {
if (s.Status.Equals(System.ServiceProcess.ServiceControllerStatus.Stopped))//check service staus
   {
bool status = ServiceStartModeUpdate("Alerter", "Manual", "Can't start service");//provide service name here and startup Type that must be automatic or manual
if (status == true)
    {
     s.Start();
    }
   }
  }
 }
}
 
private bool ServiceStartModeUpdate(string serviceName, string startMode,string errorMsg)
{
uint successReturn = 1;
errorMsg = string.Empty;
string filterService =
String.Format("SELECT * FROM Win32_Service WHERE Name = '{0}'", serviceName);
ManagementObjectSearcher querySearch = new ManagementObjectSearcher(filterService);
// No match = failed condition
if (querySearch == null)
 {
  return false;
 }
 else
 {
  try
  {
   ManagementObjectCollection services = querySearch.Get();//get that service
   foreach (ManagementObject service in services)
    {
if (Convert.ToString(service.GetPropertyValue("StartMode")) == "Disabled")//if startup type is Diasabled then change it
      {
       ManagementBaseObject inParams = service.GetMethodParameters("ChangeStartMode")  ;
       inParams["startmode"] = startMode;
       ManagementBaseObject outParams =
       service.InvokeMethod("ChangeStartMode", inParams, null);
       successReturn = Convert.ToUInt16(outParams.Properties["ReturnValue"].Value);
      }
    }
  }
   catch (Exception ex)
   {
    errorMsg = ex.Message;
    throw;
   }
  }
return (successReturn == 0);
 }
)

Just make some changes to stop a service as well.
NOTE:References to be added

1.System.Management
2.System.ServiceProcess
Namespace to be added:
using System.Management;