无法通过数据集在gridview上显示来自microsoft sql server的项目

I'm not able to display out the values i have added into my SQL database. Here is my code i have used. The initial idea was when the user entered the particular page , by default it will display out all the values in a form of a gridview. Hence, i put my SQL connection code in the page_load. I have tested my connection at the server explorer and it says ping test succeeded.I'm not able to display out the values i have a