frm_main.vb

图书管理系统 VB加SQL 数据库在文件里的DATA里 进到SQL里附加进去就可以使用了

        Me.ToolBar1.Buttons.AddRange(New System.Windows.Forms.ToolBarButton() {Me.ToolBarButton1, Me.ToolBarButton2, Me.ToolBarButton3, Me.ToolBarButton4})
        Me.ToolBar1.ButtonSize = New System.Drawing.Size(60, 50)
        Me.ToolBar1.DropDownArrows = True
        Me.ToolBar1.Location = New System.Drawing.Point(0, 0)
        Me.ToolBar1.Name = "ToolBar1"
        Me.ToolBar1.ShowToolTips = True
        Me.ToolBar1.Size = New System.Drawing.Size(584, 56)
        Me.ToolBar1.TabIndex = 0
        '
        'ToolBarButton1
        '
        Me.ToolBarButton1.Text = "借出图书"
        '
        'ToolBarButton2
        '
        Me.ToolBarButton2.Text = "归还图书"
        '
        'ToolBarButton3
        '
        Me.ToolBarButton3.Text = "续借图书"
        '
        'ToolBarButton4
        '
        Me.ToolBarButton4.Text = "退出系统"
        '
        'ImageList1
        '
        Me.ImageList1.ImageSize = New System.Drawing.Size(16, 16)
        Me.ImageList1.TransparentColor = System.Drawing.Color.Transparent
        '
        'Frm_Main
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
        Me.ClientSize = New System.Drawing.Size(584, 377)
        Me.Controls.Add(Me.ToolBar1)
        Me.IsMdiContainer = True
        Me.Menu = Me.MainMenu1
        Me.Name = "Frm_Main"
        Me.Text = "图书管理系统"
        Me.WindowState = System.Windows.Forms.FormWindowState.Maximized
        Me.ResumeLayout(False)

    End Sub

#End Region
    '加载
    Private Sub Frm_Main_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        If userSF <> "超级管理员" Then
            MenuS1.Enabled = False
            MenuS2.Enabled = False
            MenuS5.Enabled = False
        End If
        MenuW0.MdiList = True
    End Sub
    '用户管理
    Private Sub MenuS1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuS1.Click
        If GetInstanceState("Frm_User") Then
            Exit Sub
        End If
        Dim ChildFrm As Frm_User = New Frm_User
        ChildFrm.MdiParent = Me
        ChildFrm.Show()
    End Sub
    '罚款设置
    Private Sub MenuS2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuS2.Click
        Dim ChildFrm As Frm_Find = New Frm_Find
        ChildFrm.ShowDialog()
    End Sub
    '修改密码
    Private Sub MenuS3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuS3.Click
        Dim ChildFrm As Frm_PasswordChange = New Frm_PasswordChange
        ChildFrm.ShowDialog()
    End Sub
    '备份数据
    Private Sub MenuS4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuS4.Click
        Dim ChildFrm As Frm_BackupData = New Frm_BackupData
        ChildFrm.ShowDialog()
    End Sub
    '恢复数据
    Private Sub MenuS5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuS5.Click
        Dim ChildFrm As Frm_ResumeData = New Frm_ResumeData
        ChildFrm.ShowDialog()
    End Sub
    '退出系统
    Private Sub MenuS6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuS6.Click
        Application.Exit()
    End Sub
    '图书管理
    Private Sub MenuI1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuI1.Click
        If GetInstanceState("Frm_BookManage") Then
            Exit Sub
        End If
        Dim ChildFrm As Frm_BookManage = New Frm_BookManage
        ChildFrm.MdiParent = Me
        ChildFrm.Show()
    End Sub
    '学生管理
    Private Sub MenuI2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuI2.Click
        If GetInstanceState("Frm_StudentManage") Then
            Exit Sub
        End If
        Dim ChildFrm As Frm_StudentManage = New Frm_StudentManage
        ChildFrm.MdiParent = Me
        ChildFrm.Show()
    End Sub
    '图书类别管理
    Private Sub MenuI3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuI3.Click
        If GetInstanceState("Frm_CategoryManage") Then
            Exit Sub
        End If
        Dim ChildFrm As Frm_CategoryManage = New Frm_CategoryManage
        ChildFrm.MdiParent = Me
        ChildFrm.Show()
    End Sub
    '借出图书
    Private Sub MenuD1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuD1.Click
        If GetInstanceState("Frm_LendingBook") Then
            Exit Sub
        End If
        Dim ChildFrm As Frm_LendingBook = New Frm_LendingBook
        ChildFrm.MdiParent = Me
        ChildFrm.Show()
    End Sub
    '归还图书
    Private Sub MenuD2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuD2.Click
        If GetInstanceState("Frm_RestitutionBook") Then
            Exit Sub
        End If
        Dim ChildFrm As Frm_RestitutionBook = New Frm_RestitutionBook
        ChildFrm.MdiParent = Me
        ChildFrm.Show()
    End Sub
    '续借图书
    Private Sub MenuD3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuD3.Click
        If GetInstanceState("Frm_Continue") Then
            Exit Sub
        End If
        Dim ChildFrm As Frm_Continue = New Frm_Continue
        ChildFrm.MdiParent = Me
        ChildFrm.Show()
    End Sub

    '逾期管理
    Private Sub MenuD4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuD4.Click
        If GetInstanceState("Frm_Overdue") Then
            Exit Sub
        End If
        Dim ChildFrm As Frm_Overdue = New Frm_Overdue
        ChildFrm.MdiParent = Me
        ChildFrm.Show()
    End Sub
    ''图书统计
    'Private Sub MenuD5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)

    'End Sub

    '关于图书管理系统
    Private Sub MenuH1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuH1.Click
        If GetInstanceState("Frm_Help") Then
            Exit Sub
        End If
        Dim ChildFrm As Frm_Help = New Frm_Help
        ChildFrm.MdiParent = Me
        ChildFrm.Show()
    End Sub

    '判断子窗体实例状态函数，如果要打开的窗体已经处于打开状态，则把焦点定位于该窗体
    Public Function GetInstanceState(ByVal name As String) As Boolean
        '获得FrmMain窗口的子窗口的数量
        Dim i As Integer = Me.MdiChildren.Length
        '循环判断是否有名为name(形参接收的实参)的子窗口
        For i = 0 To Me.MdiChildren.Length - 1
            If Me.MdiChildren(i).Name = name Then
                '存在名为name 的子窗口，是子窗口获得焦点并返回True
                Me.MdiChildren(i).Focus()
                Return True
            End If
        Next
        '不存在名为name 的子窗口返回False
        Return False
    End Function
    '窗口层叠
    Private Sub MenuW1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuW1.Click
        Me.LayoutMdi(MdiLayout.Cascade)
    End Sub
    '水平平铺
    Private Sub MenuW2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuW2.Click
        Me.LayoutMdi(MdiLayout.TileHorizontal)
    End Sub
    '垂直平铺
    Private Sub MenuW3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuW3.Click
        Me.LayoutMdi(MdiLayout.TileVertical)
    End Sub

    '排列图标
    Private Sub MenuW4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuW4.Click
        Me.LayoutMdi(MdiLayout.ArrangeIcons)
    End Sub
    '窗体的Closed事件
    Private Sub Frm_Main_Closed(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Closed
        Application.Exit()
    End Sub
    '工具栏的单击事件
    Private Sub ToolBar1_ButtonClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.ToolBarButtonClickEventArgs) Handles ToolBar1.ButtonClick
        If e.Button.Text = "借出图书" Then
            If GetInstanceState("Frm_LendingBook") Then
                Exit Sub
            End If
            Dim ChildFrm As Frm_LendingBook = New Frm_LendingBook
            ChildFrm.MdiParent = Me
            ChildFrm.Show()
        ElseIf e.Button.Text = "归还图书" Then
            If GetInstanceState("Frm_RestitutionBook") Then
                Exit Sub
            End If
            Dim ChildFrm As Frm_RestitutionBook = New Frm_RestitutionBook
            ChildFrm.MdiParent = Me
            ChildFrm.Show()
        ElseIf e.Button.Text = "续借图书" Then
            If GetInstanceState("Frm_Continue") Then
                Exit Sub
            End If
            Dim ChildFrm As Frm_Continue = New Frm_Continue
            ChildFrm.MdiParent = Me
            ChildFrm.Show()
        ElseIf e.Button.Text = "退出系统" Then
            Application.Exit()
        End If
    End Sub

End Class