vb.net - Click on a button to dispaly the next record in Ms Access Database -


i have records in dsatabase in access, table called "add form". have created form in vb delete selected record record table show in respective textboxes , user click delete delete record , either click next\previous navigate record. code next button: 

if inc <> maxrows - 1     inc = maxrows - 1     navigaterecords() elseif inc = -1     msgbox("this first record") end if

the navigate function here :

private sub navigaterecords()     student_idtextbox.text = ds.tables("add form").rows(inc).item(0)     student_nametextbox.text = ds.tables("add form").rows(inc).item(1)     date_of_birthdatetimepicker.text = ds.tables("add form").rows(inc).item(2)     addresstextbox.text = ds.tables("add form").rows(inc).item(3)     e_mailtextbox.text = ds.tables("add form").rows(inc).item(4)     allergiestextbox.text = ds.tables("add form").rows(inc).item(5)     emergency_contact_numbertextbox.text = ds.tables("add form").rows(inc).item(6) end sub

but giving me error:

object reference not set instance of object.

for first line of code under navigate sub.

please me program button go next record in database.


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