form1.vb

用vb.net写的基于c/s结构的进销存程序设计源代码

Public Class Form1
    Inherits System.Windows.Forms.Form
    Dim WithEvents cnNorthwind As New SqlClient.SqlConnection()
#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

    '窗体重写处置以清理组件列表。
    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 bnOpen As System.Windows.Forms.Button
    Friend WithEvents bnChangeDatabase As System.Windows.Forms.Button
    Friend WithEvents bnClose As System.Windows.Forms.Button
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.bnOpen = New System.Windows.Forms.Button()
        Me.bnChangeDatabase = New System.Windows.Forms.Button()
        Me.bnClose = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        '
        'bnOpen
        '
        Me.bnOpen.Location = New System.Drawing.Point(72, 32)
        Me.bnOpen.Name = "bnOpen"
        Me.bnOpen.Size = New System.Drawing.Size(136, 24)
        Me.bnOpen.TabIndex = 0
        Me.bnOpen.Text = "连接到NorthWind"
        '
        'bnChangeDatabase
        '
        Me.bnChangeDatabase.Location = New System.Drawing.Point(72, 84)
        Me.bnChangeDatabase.Name = "bnChangeDatabase"
        Me.bnChangeDatabase.Size = New System.Drawing.Size(136, 24)
        Me.bnChangeDatabase.TabIndex = 1
        Me.bnChangeDatabase.Text = "切换到pubs"
        '
        'bnClose
        '
        Me.bnClose.Location = New System.Drawing.Point(72, 136)
        Me.bnClose.Name = "bnClose"
        Me.bnClose.Size = New System.Drawing.Size(136, 24)
        Me.bnClose.TabIndex = 2
        Me.bnClose.Text = "关闭"
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
        Me.ClientSize = New System.Drawing.Size(292, 273)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.bnClose, Me.bnChangeDatabase, Me.bnOpen})
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)

    End Sub

#End Region

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        bnClose.Enabled = False
        bnChangeDatabase.Enabled = False
    End Sub

    Private Sub bnOpen_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnOpen.Click
        cnNorthwind.ConnectionString = _
            "Data Source=localhost;" & _
            "Initial Catalog=NorthWind;" & _
            "Integrated Security=SSPI;"
        cnNorthwind.Open()
    End Sub

    Private Sub bnChangeDatabase_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnChangeDatabase.Click
        cnNorthwind.ChangeDatabase("pubs")
    End Sub

    Private Sub cnNorthwind_StateChange(ByVal sender As Object, ByVal e As System.Data.StateChangeEventArgs) Handles cnNorthwind.StateChange
        bnOpen.Enabled = (cnNorthwind.State = ConnectionState.Closed)
        bnChangeDatabase.Enabled = (cnNorthwind.State = ConnectionState.Open)
        bnClose.Enabled = (cnNorthwind.State = ConnectionState.Open)
    End Sub

    Private Sub cnNorthwind_InfoMessage(ByVal sender As Object, ByVal e As System.Data.SqlClient.SqlInfoMessageEventArgs) Handles cnNorthwind.InfoMessage
        Dim eErr As SqlClient.SqlError
        For Each eErr In e.Errors
            MessageBox.Show(eErr.Message, "错误等级" & eErr.Class, _
                MessageBoxButtons.OK, MessageBoxIcon.Information)
        Next
    End Sub

    Private Sub bnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bnClose.Click
        cnNorthwind.Close()
        cnNorthwind.Dispose()
        cnNorthwind.ConnectionString = Nothing
    End Sub
End Class