是登入界面
Imports System.Data.SqlClient.SqlException
Imports System.Data.SqlClient
Public Class login
Inherits System.Windows.Forms.Form
#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 GroupBox1 As System.Windows.Forms.GroupBox
Friend WithEvents Label1 As System.Windows.Forms.Label
Friend WithEvents ComboBox1 As System.Windows.Forms.ComboBox
Friend WithEvents Label2 As System.Windows.Forms.Label
Friend WithEvents TextBox1 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()
Me.GroupBox1 = New System.Windows.Forms.GroupBox
Me.TextBox1 = New System.Windows.Forms.TextBox
Me.Label2 = New System.Windows.Forms.Label
Me.ComboBox1 = New System.Windows.Forms.ComboBox
Me.Label1 = New System.Windows.Forms.Label
Me.Button1 = New System.Windows.Forms.Button
Me.Button2 = New System.Windows.Forms.Button
Me.GroupBox1.SuspendLayout()
Me.SuspendLayout()
'
'GroupBox1
'
Me.GroupBox1.Controls.Add(Me.TextBox1)
Me.GroupBox1.Controls.Add(Me.Label2)
Me.GroupBox1.Controls.Add(Me.ComboBox1)
Me.GroupBox1.Controls.Add(Me.Label1)
Me.GroupBox1.Location = New System.Drawing.Point(40, 32)
Me.GroupBox1.Name = "GroupBox1"
Me.GroupBox1.Size = New System.Drawing.Size(296, 152)
Me.GroupBox1.TabIndex = 0
Me.GroupBox1.TabStop = False
Me.GroupBox1.Text = "管理员登陆"
'
'TextBox1
'
Me.TextBox1.Location = New System.Drawing.Point(128, 88)
Me.TextBox1.Name = "TextBox1"
Me.TextBox1.PasswordChar = Microsoft.VisualBasic.ChrW(42)
Me.TextBox1.Size = New System.Drawing.Size(120, 21)
Me.TextBox1.TabIndex = 3
Me.TextBox1.Text = ""
'
'Label2
'
Me.Label2.Location = New System.Drawing.Point(24, 88)
Me.Label2.Name = "Label2"
Me.Label2.TabIndex = 2
Me.Label2.Text = "密码"
'
'ComboBox1
'
Me.ComboBox1.Location = New System.Drawing.Point(128, 32)
Me.ComboBox1.Name = "ComboBox1"
Me.ComboBox1.Size = New System.Drawing.Size(121, 20)
Me.ComboBox1.TabIndex = 1
'
'Label1
'
Me.Label1.Location = New System.Drawing.Point(24, 32)
Me.Label1.Name = "Label1"
Me.Label1.TabIndex = 0
Me.Label1.Text = "姓名"
'
'Button1
'
Me.Button1.Location = New System.Drawing.Point(80, 224)
Me.Button1.Name = "Button1"
Me.Button1.TabIndex = 1
Me.Button1.Text = "登陆"
'
'Button2
'
Me.Button2.Location = New System.Drawing.Point(216, 224)
Me.Button2.Name = "Button2"
Me.Button2.TabIndex = 2
Me.Button2.Text = "取消"
'
'login
'
Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
Me.BackColor = System.Drawing.SystemColors.ScrollBar
Me.ClientSize = New System.Drawing.Size(394, 287)
Me.ControlBox = False
Me.Controls.Add(Me.Button2)
Me.Controls.Add(Me.Button1)
Me.Controls.Add(Me.GroupBox1)
Me.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog
Me.MaximizeBox = False
Me.MinimizeBox = False
Me.Name = "login"
Me.Text = "欢迎登陆"
Me.GroupBox1.ResumeLayout(False)
Me.ResumeLayout(False)
End Sub
#End Region
Private Sub login_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'将管理员姓名和密码读入到ComboBox1中
' Dim mycon As New SqlConnection(constr)
If mycon.State = ConnectionState.Closed Then
mycon.Open()
End If
Dim myread As SqlDataReader
Dim sqlstr As String = "select Name from Administrator"
Dim mycom As New SqlCommand(sqlstr, mycon)
myread = mycom.ExecuteReader
'从数据阅读器中读数据到ComboBox1中，注意条件的判定
While myread.Read
ComboBox1.Items.Add(myread("Name"))
End While
ComboBox1.SelectedIndex = 0
ad = ComboBox1.Text
ComboBox1.Focus()
mycon.Close()
End Sub
Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
If Asc(e.KeyChar) = System.Windows.Forms.Keys.Enter Then
Button1.PerformClick()
End If
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'登陆按钮的代码
'首先验证输入数据的合法性
If ComboBox1.Text = "" Or TextBox1.Text = "" Then
MessageBox.Show("用户名或密码不能为空", "提醒", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
Exit Sub
End If
If mycon.State = ConnectionState.Closed Then
mycon.Open()
End If
' Dim i As Integer
' Dim t As Integer = 3
' For i = 0 To 2
Dim sqlstr As String = "select Count(*) from Administrator Where Name='" & ComboBox1.SelectedItem & "' and Password='" & TextBox1.Text & "'"
Dim mycom As New SqlCommand(sqlstr, mycon)
If mycom.ExecuteScalar <> 1 Then
' MessageBox.Show("恭喜你登陆成功!", "提醒", MessageBoxButtons.OK, MessageBoxIcon.Information)
' If t <> i + 1 Then
MessageBox.Show("密码错误!请重新输入！", "提醒", MessageBoxButtons.OK, MessageBoxIcon.Warning)
TextBox1.Text = ""
ComboBox1.SelectedIndex = 0
Exit Sub
' ElseIf t = i + 1 Then
' MessageBox.Show("你已经输入错误的密码三次,请下次登陆!", "提醒", MessageBoxButtons.OK, MessageBoxIcon.Warning)
' Me.Close()
' Application.Exit() '这段代码不能执行成功,好好
' End If
' End If
' Next i
Else
MessageBox.Show("恭喜你登陆成功!", "提醒", MessageBoxButtons.OK, MessageBoxIcon.Information)
End If
Me.Close()
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Application.Exit()
End Sub
Private Sub login_Activated(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Activated
End Sub
End Class
运行提示错误：未处理的“System.Data.SqlClient.SqlException”类型的异常出现在 system.data.dll 中。
其他信息: 系统错误。
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