I have Gridview with Template Field.And I Put Dropdownlist at footer row of gridview. but when i insert the value from a database table in dropdownlist , than it generate error.
for filling value ,

i declare variable like in databound event of gridview.
for example:

dim varclass as new dropdownlist
varclass=Gridvi ew1.footerRow.f indcontrol("ddl Class")

it generate error...