登录窗体Form1：I
mports System.Data
Imports System.Data.SqlClient
Public Class Form1
Private Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim myconn As New SqlConnection("UID=sa;password=sa;database=图书管理系统;server=(Local)")
Dim str1 As String = "select 工号,密码from 管理员where 工号='" & TextBox1.Text & "'and 密码='" & TextBox2.Text & "'"
Dim str2 As String = "select 读者ID,密码from 读者where 读者ID='" & TextBox1.Text & "'and 密码='" & TextBox2.Text & "'"
用户名= TextBox1.Text
If RadioButton1.Checked Then
Dim mycmd As New SqlCommand(str1, myconn)
myconn.Open()
Dim myReader As SqlDataReader
myReader = mycmd.ExecuteReader()
If myReader.HasRows = False Then
MsgBox("用户名或密码错误!请确认后再登录!")
TextBox1.Text = ""
TextBox2.Text = ""
TextBox1.Focus()
Else
Form2.Show()
Me.Hide()
End If
ElseIf RadioButton2.Checked Then
Dim mycmd As New SqlCommand(str2, myconn)
myconn.Open()
Dim myReader As SqlDataReader
myReader = mycmd.ExecuteReader()
If myReader.HasRows = False Then
MsgBox("用户名或密码错误!请确认后在登录!")
TextBox1.Text = ""
TextBox2.Text = ""
TextBox1.Focus()
Else
Form3.Show()
Me.Hide()
End If
End If
myconn.Close()
End Sub
