I am doing a project entitled "Automation of Student admission process".I am having a datafield UGPercent of datatype(18,3) NULL in my database.When i tried to insert it using the following code
Insert into Markdetail(UGPe rcent)values(" & txtperc2.Text & ")..
It shows me the error:conversio n from string to double is not valid.

what is wrong in my code?

here: Markdetail is my...