登录.vb

一个自己开发的学生信息管理系统哦

Public Class 登录
    mports System
Imports System.Date
Imports System.Date.SqlClient
  Dim i AsInteger=3
    Dim strsql As String
    Dim strconn As String
    Dim objcommand As SqlClient.SqlCommand
    Dim objdr As SqlClient.SqlDataReader
    Dim str1, str2 As String

    Private Sub 登录_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub Label1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click

    End Sub
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        TextBox1.Text = ""
        TextBox2.Text = ""
        TextBox1.Focus()
    End Sub
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        strconn = "date source=cheng;initial catalog=学生成绩管理系统；use id=sa;password=;"
        strsql = "select 用户名，密码from用户表"
        objcommand = New SqlClient.SqlCommand(strsql, New SqlClient.SqlConnection(strconn))
        objcommand.Connection.Open()
        objdr=objcommand.ExecuteReader(CommandBehavior.CloseConnection(strconn)
        With objdr
            Do While .Read = Ture
                str1 = .GetString(0)
                str2 = .GetString(1)
                If Trim(TextBox1.Text) = Trim(str1) And Trim(TextBox2.Text) = Trim(str2) Then
                    MessageBox.Show("恭喜登录成功", "系统提示", MessageBoxButtons.OK, MessageBoxIcon.Information)
                    主窗体.Show()
                    Me.Visible = False
                    Exit Sub
                End If
            Loop
        End With
        i = i - 1
        If i = 0 Then
            MessageBox.Show("你已经没有登陆机会了，Bye！", "系统提示", MessageBoxButtons.OK, MessageBoxIcon.Hand)
            Me.Close()
        Else
            MessageBox.Show("登录失败" + "你还有" + Str(i) + "次登录机会", "系统提示", MessageBoxButtons.OK, MessageBoxIcon.Error)
            TextBox1.Text = ""
            TextBox2.Text = ""
            TextBox1.Focus()




        End If

    End Sub
End Class