Entering all students marks at a time based on their regd no's. in C# using ASP

hi friends ,

  please help me in solving the below  issue in  C# using ASP..


I want to enter marks of all the students at a time . so after clicking upload button all the marks has to be uploaded in the corresponding fields in the database .

  for this i need REGDNO and NAME should be displayed automatically when I select the branch in dropdown. For MARKS  there should be a  TEXTBOX such that all the marks can be entered  at a time.

  SO marks has to be stored in the database according to their rollno.

DATABASE
REGDNO	NAME	MARKS
04331A1201	CHIRANJEEVI
04331A1202	VENUKUMAR
04331A1203	NAVEENKUMAR
04331A1204	HARISH
04331A1205	SATISH
04331A1206	GUPTA

  design page:
 

INTERNAL MARKS(20)
REGDNO	NAME	MARKS
04331A1201	CHIRANJEEVI	18
04331A1202	VENUKUMAR	15
04331A1203	NAVEENKUMAR	17
04331A1204	HARISH	19
04331A1205	SATISH	18
04331A1206	GUPTA	14
	upload marks