form1.vb

这是一个基于.NET平台

Imports System.Data
Imports System.Data.SqlClient

Public Class Form1
    Inherits System.Windows.Forms.Form
     Public myrow As Data.DataRow
    '建立数据行对象
     Dim user As String
    Dim title As String = "工资管理系统"
    Dim time As Integer = 0
   
#Region " Windows 窗体设计器生成的代码 "

    Public Sub New()
        MyBase.New()

        '该调用是 Windows 窗体设计器所必需的。
        InitializeComponent()

        '在 InitializeComponent() 调用之后添加任何初始化

    End Sub

    '窗体重写 dispose 以清理组件列表。
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Windows 窗体设计器所必需的
    Private components As System.ComponentModel.IContainer

    '注意: 以下过程是 Windows 窗体设计器所必需的
    '可以使用 Windows 窗体设计器修改此过程。
    '不要使用代码编辑器修改它。
    Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
    Friend WithEvents TextBox2 As System.Windows.Forms.TextBox
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents Button2 As System.Windows.Forms.Button
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Dim resources As System.Resources.ResourceManager = New System.Resources.ResourceManager(GetType(Form1))
        Me.TextBox1 = New System.Windows.Forms.TextBox
        Me.TextBox2 = New System.Windows.Forms.TextBox
        Me.Button1 = New System.Windows.Forms.Button
        Me.Button2 = New System.Windows.Forms.Button
        Me.SuspendLayout()
        '
        'TextBox1
        '
        Me.TextBox1.Location = New System.Drawing.Point(168, 112)
        Me.TextBox1.Name = "TextBox1"
        Me.TextBox1.TabIndex = 2
        Me.TextBox1.Text = ""
        '
        'TextBox2
        '
        Me.TextBox2.Location = New System.Drawing.Point(168, 144)
        Me.TextBox2.Name = "TextBox2"
        Me.TextBox2.PasswordChar = Microsoft.VisualBasic.ChrW(42)
        Me.TextBox2.TabIndex = 3
        Me.TextBox2.Text = ""
        '
        'Button1
        '
        Me.Button1.BackColor = System.Drawing.SystemColors.ActiveCaptionText
        Me.Button1.Font = New System.Drawing.Font("宋体", 9.0!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(134, Byte))
        Me.Button1.Location = New System.Drawing.Point(72, 192)
        Me.Button1.Name = "Button1"
        Me.Button1.TabIndex = 4
        Me.Button1.Text = "登录"
        '
        'Button2
        '
        Me.Button2.BackColor = System.Drawing.SystemColors.ActiveCaptionText
        Me.Button2.Font = New System.Drawing.Font("宋体", 9.0!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(134, Byte))
        Me.Button2.Location = New System.Drawing.Point(216, 192)
        Me.Button2.Name = "Button2"
        Me.Button2.TabIndex = 5
        Me.Button2.Text = "退出"
        '
        'Form1
        '
        Me.AcceptButton = Me.Button1
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
        Me.BackgroundImage = CType(resources.GetObject("$this.BackgroundImage"), System.Drawing.Image)
        Me.ClientSize = New System.Drawing.Size(392, 245)
        Me.Controls.Add(Me.Button2)
        Me.Controls.Add(Me.Button1)
        Me.Controls.Add(Me.TextBox2)
        Me.Controls.Add(Me.TextBox1)
        Me.Name = "Form1"
        Me.Text = "系统登录"
        Me.ResumeLayout(False)

    End Sub

#End Region


    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim strCon As String
        strCon = "Server=(local); Database=mydb; User Id=sa; Password=;"
        If TextBox1.Text = "" Then
            MsgBox("请输入用户名！")
            TextBox1.Focus()

        ElseIf TextBox2.Text = "" Then
            MsgBox("请输入密码！")
            TextBox2.Focus()
        Else
            time += 1

            Dim tablename As String
            tablename = "users"  '表的名称
            Dim SearchSQL As String
            SearchSQL = "SELECT * FROM users WHERE username = '" & TextBox1.Text & " '"
            Try
                Try
                    Dim ADOcmd As SqlDataAdapter
                    '建立DataSet对象 
                    Dim ds As DataSet = New DataSet '建立ADODataSetCommand对象

                    Dim mytable As DataTable
                    Dim rownumber As Integer '定义一个整型变量来存放当前行数

                    '建立表单对象
                    ADOcmd = New SqlDataAdapter(SearchSQL, strCon)

                    '建立ADODataSetCommand对象
                    ADOcmd.Fill(ds, tablename) '取得表单
                    mytable = ds.Tables.Item(0) '取得名为table的表
                    rownumber = 0 '设置为第一行
                    myrow = mytable.Rows.Item(rownumber)
                    '取得第一行数据
                Catch
                    MsgBox(Err.Description)
                End Try
                Dim s As String
                s = myrow.Item(1)
                s = s.Trim
                If s = TextBox2.Text Then  '比较输入密码和数据库的密码
                    Dim main As New Form2
                    main.Show()
                    Me.Hide()
                ElseIf time >= 3 Then
                    MsgBox("您已经三次进入本系统，均不成功，系统将关闭！")
                    End
                Else
                    MsgBox("密码不正确，请重新输入！")
                    TextBox2.Text = ""
                End If

            Catch
                MsgBox("没有该用户", vbOKOnly + vbExclamation, "警告")

            End Try
        End If

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        '退出系统 Exit Sub
        Dim Actuser As String = user
        If MsgBox("您真的要退出?", MsgBoxStyle.OKCancel, title) = MsgBoxResult.OK Then
            Me.Dispose()
        End If
        'Call bye(Actuser)
    End Sub

    Private Sub Form1_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
        Dim actuser As String = user
        If MsgBox("您真的要退出?", MsgBoxStyle.OKCancel, title) = MsgBoxResult.OK Then
            '退出
            e.Cancel = False
            Application.Exit()
        Else
            '不退出
            e.Cancel = True
        End If
        'Call bye(actuser)
    End Sub
End Class