In the forum, I often see some friends in the vb version asking questions about login. This article provides some help for beginners. Of course, I hope that experts with better methods can give advice.
First file → new → project select windows application and add two label controls, two textbox controls, and two buton controls on the form, such as (1-1 ):
After the interface is designed, write the following code in the button click event:
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(Reference imports system. Data. oledb at the top of the Program) Private sub bok_click (byval sender as system. Object, byval e as system. eventargs) handles Bok. Click
'Definition
Dim olecn as new oledbconnection ("provider = Microsoft. Jet. oledb.4.0; Data Source = data. mdb ")
Dim olecm as new oledbcommand ("select * from login", olecn)
Dim olead as new oledbdataadapter
Dim olerd as oledbdatareader
Dim PD as Boolean = false' is defined as Boolean for subsequent error handling.
Dim I as integer
Olecm = new oledbcommand ("select * from login", olecn)
'Establish a connection with the database
Olecn. open ()
Olerd = olecm. executereader
'Cyclically determine whether the data in the database is the same
Do While olerd. Read ()
For I = 0 to olerd. fieldcount-1
If trim (Tuser. Text) = (olerd. Item ("account") and trim (tpassword. Text) = (olerd. Item ("password") then
Msgbox ("successfully logged on ")
Pd = true
Exit sub
End if
Next
Loop
Tuser. Text = ""
Tpassword. Text = ""
Tuser. Focus ()
Olerd. Close ()
Olecn. Close ()
End sub |
The whole process is complete.
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