GPIO Just blink once

Hi,

I'm trying to light up a led for 10 seconds with this code
But the led only blink once very fast.

Is there a way to keep the GPIO on for several seconds

This is my code

UInt32 err = EAPI.EApiLibInitialize();
                    if (err != EAPI.EAPI_STATUS_INITIALIZED)
                    {
                        Console.WriteLine("Can't initialize the application: " + err.ToString());
                        Environment.Exit(0);
                    }
                    UInt32 nPinCount = 0;
                    UInt32 bDioDisable = 0;

                    EAPI.EApiGPIOGetCaps(EAPI.EAPI_GPIO_GPIO_ID((UInt32)relayNumber), ref nPinCount, ref bDioDisable);
                    if (bDioDisable != 0x01)
                    {
                        err = EAPI.EApiGPIOSetDirection(EAPI.EAPI_GPIO_GPIO_ID((UInt32)relayNumber), 0xFFFFFFFF, EAPI.EAPI_GPIO_OUTPUT);
                        err = EAPI.EApiGPIOSetLevel(EAPI.EAPI_GPIO_GPIO_ID((UInt32)relayNumber), 0xFFFFFFFF, EAPI.EAPI_GPIO_HIGH);
                        Console.WriteLine("Pull relay for {0} seconds.", 10);
                        System.Threading.Thread.Sleep(10000);
                        err = EAPI.EApiGPIOSetDirection(EAPI.EAPI_GPIO_GPIO_ID((UInt32)relayNumber), 0xFFFFFFFF, EAPI.EAPI_GPIO_OUTPUT);
                        err = EAPI.EApiGPIOSetLevel(EAPI.EAPI_GPIO_GPIO_ID((UInt32)relayNumber), 0xFFFFFFFF, EAPI.EAPI_GPIO_LOW);
                        Console.WriteLine("###############  COMPLETED  ##################");
                    } else
                    {
                        Console.WriteLine("###############  GPIO Disabled  ##################");
                    }