使用 MySQL 数据库的 VB.NET 登录表单
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VB.NET log in form using MySQL database
提问by user3765415
Can someone help me with the following please.
有人可以帮我解决以下问题吗？
I have created a database called dbhr and a table in it called user with two fields 'username' and 'password' having VARCHAR data type. I have a log in form with two textboxes (tbxUsername,tbxPassword) and an OK button. I have connected my database to authenticate the username and password. But it always give me wrong password message. I don't know where I went wrong. Please help.
我创建了一个名为 dbhr 的数据库和一个名为 user 的表，其中包含两个具有 VARCHAR 数据类型的字段“用户名”和“密码”。我有一个登录表单，其中包含两个文本框（tbxUsername、tbxPassword）和一个 OK 按钮。我已经连接了我的数据库来验证用户名和密码。但它总是给我错误的密码信息。我不知道我哪里错了。请帮忙。
I use MySQL Workbench 6.1
我使用 MySQL Workbench 6.1
Thanks in advance.
提前致谢。
Here is the VB.NET log in button code.
这是 VB.NET 登录按钮代码。
Imports MySql.Data.MySqlClient
Public Class Login
Dim mydbcon As MySqlConnection
Dim COMMAND As MySqlCommand
' TODO: Insert code to perform custom authentication using the provided username and password
' (See http://go.microsoft.com/fwlink/?LinkId=35339).
' The custom principal can then be attached to the current thread's principal as follows:
' My.User.CurrentPrincipal = CustomPrincipal
' where CustomPrincipal is the IPrincipal implementation used to perform authentication.
' Subsequently, My.User will return identity information encapsulated in the CustomPrincipal object
' such as the username, display name, etc.
Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click
mydbcon = New MySqlConnection
mydbcon.ConnectionString = "server=localhost;userid=root;password=rootword;database=hrdb"
Dim reader As MySqlDataReader
Try
mydbcon.Open()
Dim Query As String
Query = "select * from user where username= ' " & tbxUsername.Text & "' and password= ' " & tbxPassword.Text & "' "
COMMAND = New MySqlCommand(Query, mydbcon)
reader = COMMAND.ExecuteReader
Dim count As Integer
count = 0
While reader.Read
count = count + 1
End While
If count = 1 Then
MessageBox.Show("Username and password are correct")
ElseIf count > 1 Then
MessageBox.Show("Username and password are duplicate")
Else
MessageBox.Show("Username and password are wrong")
End If
mydbcon.Close()
Catch ex As MySqlException
MessageBox.Show(ex.Message)
Finally
mydbcon.Dispose()
End Try
End Sub
Please click the following links to see the database table records and data types.
请点击以下链接查看数据库表记录和数据类型。
Click here!
点击这里！
采纳答案by djv
You have some extra spaces in the line
您在该行中有一些额外的空格
Query = "select * from user where username= ' " & tbxUsername.Text & "' and password= ' " & tbxPassword.Text & "' "
which I would change to
我会改为
Query = String.Format("SELECT * FROM user WHERE username = '{0}' AND password = '{1}'", Me.tbxUsername.Text.Trim(), Me.tbxPassword.Text.Trim())
I would use String.Format()to make it clearer, less chance to overlook those extra spaces.
我会String.Format()用来使它更清晰，减少忽略那些额外空间的机会。
