In this guide, I’ll be showing you how to create a login application in visual studio using the language vb.net and the database mysql.
Be sure you already know how to connect your vb.net application to your mysql database before proceeding.
First thing that you’ll gonna need to do is to create a subroutine in which you will put these lines of code:
cmd.CommandText = "SELECT * FROM testdb WHERE Name='" & name & "' AND Password='" & course & "'" Try Dim uname As String Dim pword As String rdr = cmd.ExecuteReader If rdr.HasRows Then rdr.Read() uname = rdr("Name") pword = rdr("Password") If (name = uname And password = pword) Then form2.show() Else MsgBox("Incorrect Admin Information, please try again", MsgBoxStyle.Information) End If Catch MsgBox("Something went wrong..") End Try
Breaking it down:
First we declared the command or the query to be used to get information from the database:
cmd.CommandText = "SELECT * FROM testdb WHERE Name='" & name & "' AND Password='" & course & "'"
Then we placed a try catch statement to catch whatever errors we might get so that it won’t make the program crash like IE.
Try Catch ex As Exception End Try
Then inside the try-catch, declare the variables that we will use to store the value that were going to read from the database.
Dim uname as String Dim pword as String
Then go outside the subroutine block. And declare the data reader
Dim rdr as odbcDataReader
Go inside the subroutine block again. And set the data reader that you have just declared to use a command.
rdr = cmd.ExecuteReader
If you haven’t declared a command yet. Then declare it outside the subroutine.
Dim cmd as odbcCommand
All you have to do now is to read the data from the specific fields in the database. Set it to a variable. Then compare the values that the user inputted. In this case the public string name and password.
If rdr.HasRows Then rdr.Read() uname = rdr("Name") pword = rdr("Password") If (name = uname And password = pword) Then Form2.show Else MsgBox("Incorrect Admin Information, please try again", MsgBoxStyle.Information) End If
Then go to your login form designer view. And create an object for the class where you have made a subroutine.
Dim x as new NameOfClass
Then use this object to call the subroutines from the button click event.
x.name=textbox1.text x.password=textbox2.text x.loginsub()
That’s it, now you have created a vb.net login application that connects to the mysql database.