1  Public Sub connect()
 2         Dim pass As Boolean
 3         pass = False
 4         Dim conn As New SqlConnection
 5         Dim rs As New SqlCommand
 6         Dim dataread As SqlDataReader
 7         Dim constr As String
 8         'Dim i As Integer
 9         Dim sql As String
10         constr = "server=PC-201105311336\SQLEXPRESS;Uid=sa;Pwd=123456;Database=jiaxiaoai" '无源连接
11         conn = New SqlConnection(constr)
12         conn.Open()
13         sql = "select * from sysname"
14         rs = New SqlCommand(sql, conn)
15         dataread = rs.ExecuteReader()
16 
17         While (dataread.Read)
18             If dataread(0).ToString = usertext.Text And dataread(1).ToString = passwordtext.Text Then
19                 pass = True
20             End If
21         End While
22 
23         If pass = True Then
24             Me.Hide()
25             显示学生信息.Show()
26         Else
27             MsgBox("用户名或密码错误")
28         End If
29 
30     End Sub