form1.vb

Source code for VB.NET book - Chapter 6

Public Class Form1
    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 OleDbDataAdapter1 As System.Data.OleDb.OleDbDataAdapter
    Friend WithEvents OleDbSelectCommand1 As System.Data.OleDb.OleDbCommand
    Friend WithEvents OleDbInsertCommand1 As System.Data.OleDb.OleDbCommand
    Friend WithEvents OleDbUpdateCommand1 As System.Data.OleDb.OleDbCommand
    Friend WithEvents OleDbDeleteCommand1 As System.Data.OleDb.OleDbCommand
    Friend WithEvents OleDbConnection1 As System.Data.OleDb.OleDbConnection
    Friend WithEvents OleDbCommand1 As System.Data.OleDb.OleDbCommand
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents RichTextBox1 As System.Windows.Forms.RichTextBox
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.OleDbDataAdapter1 = New System.Data.OleDb.OleDbDataAdapter
        Me.OleDbSelectCommand1 = New System.Data.OleDb.OleDbCommand
        Me.OleDbInsertCommand1 = New System.Data.OleDb.OleDbCommand
        Me.OleDbUpdateCommand1 = New System.Data.OleDb.OleDbCommand
        Me.OleDbDeleteCommand1 = New System.Data.OleDb.OleDbCommand
        Me.OleDbConnection1 = New System.Data.OleDb.OleDbConnection
        Me.OleDbCommand1 = New System.Data.OleDb.OleDbCommand
        Me.Button1 = New System.Windows.Forms.Button
        Me.RichTextBox1 = New System.Windows.Forms.RichTextBox
        Me.SuspendLayout()
        '
        'OleDbDataAdapter1
        '
        Me.OleDbDataAdapter1.DeleteCommand = Me.OleDbDeleteCommand1
        Me.OleDbDataAdapter1.InsertCommand = Me.OleDbInsertCommand1
        Me.OleDbDataAdapter1.SelectCommand = Me.OleDbSelectCommand1
        Me.OleDbDataAdapter1.TableMappings.AddRange(New System.Data.Common.DataTableMapping() {New System.Data.Common.DataTableMapping("Table", "Employees", New System.Data.Common.DataColumnMapping() {New System.Data.Common.DataColumnMapping("EmployeeID", "EmployeeID"), New System.Data.Common.DataColumnMapping("LastName", "LastName"), New System.Data.Common.DataColumnMapping("FirstName", "FirstName")})})
        Me.OleDbDataAdapter1.UpdateCommand = Me.OleDbUpdateCommand1
        '
        'OleDbSelectCommand1
        '
        Me.OleDbSelectCommand1.CommandText = "SELECT EmployeeID, LastName, FirstName FROM Employees"
        Me.OleDbSelectCommand1.Connection = Me.OleDbConnection1
        '
        'OleDbInsertCommand1
        '
        Me.OleDbInsertCommand1.CommandText = "INSERT INTO Employees(LastName, FirstName) VALUES (?, ?); SELECT EmployeeID, Last" & _
        "Name, FirstName FROM Employees WHERE (EmployeeID = @@IDENTITY)"
        Me.OleDbInsertCommand1.Connection = Me.OleDbConnection1
        Me.OleDbInsertCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("LastName", System.Data.OleDb.OleDbType.VarWChar, 20, "LastName"))
        Me.OleDbInsertCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("FirstName", System.Data.OleDb.OleDbType.VarWChar, 10, "FirstName"))
        '
        'OleDbUpdateCommand1
        '
        Me.OleDbUpdateCommand1.CommandText = "UPDATE Employees SET LastName = ?, FirstName = ? WHERE (EmployeeID = ?) AND (Firs" & _
        "tName = ?) AND (LastName = ?); SELECT EmployeeID, LastName, FirstName FROM Emplo" & _
        "yees WHERE (EmployeeID = ?)"
        Me.OleDbUpdateCommand1.Connection = Me.OleDbConnection1
        Me.OleDbUpdateCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("LastName", System.Data.OleDb.OleDbType.VarWChar, 20, "LastName"))
        Me.OleDbUpdateCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("FirstName", System.Data.OleDb.OleDbType.VarWChar, 10, "FirstName"))
        Me.OleDbUpdateCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("Original_EmployeeID", System.Data.OleDb.OleDbType.Integer, 4, System.Data.ParameterDirection.Input, False, CType(0, Byte), CType(0, Byte), "EmployeeID", System.Data.DataRowVersion.Original, Nothing))
        Me.OleDbUpdateCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("Original_FirstName", System.Data.OleDb.OleDbType.VarWChar, 10, System.Data.ParameterDirection.Input, False, CType(0, Byte), CType(0, Byte), "FirstName", System.Data.DataRowVersion.Original, Nothing))
        Me.OleDbUpdateCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("Original_LastName", System.Data.OleDb.OleDbType.VarWChar, 20, System.Data.ParameterDirection.Input, False, CType(0, Byte), CType(0, Byte), "LastName", System.Data.DataRowVersion.Original, Nothing))
        Me.OleDbUpdateCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("Select_EmployeeID", System.Data.OleDb.OleDbType.Integer, 4, "EmployeeID"))
        '
        'OleDbDeleteCommand1
        '
        Me.OleDbDeleteCommand1.CommandText = "DELETE FROM Employees WHERE (EmployeeID = ?) AND (FirstName = ?) AND (LastName = " & _
        "?)"
        Me.OleDbDeleteCommand1.Connection = Me.OleDbConnection1
        Me.OleDbDeleteCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("Original_EmployeeID", System.Data.OleDb.OleDbType.Integer, 4, System.Data.ParameterDirection.Input, False, CType(0, Byte), CType(0, Byte), "EmployeeID", System.Data.DataRowVersion.Original, Nothing))
        Me.OleDbDeleteCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("Original_FirstName", System.Data.OleDb.OleDbType.VarWChar, 10, System.Data.ParameterDirection.Input, False, CType(0, Byte), CType(0, Byte), "FirstName", System.Data.DataRowVersion.Original, Nothing))
        Me.OleDbDeleteCommand1.Parameters.Add(New System.Data.OleDb.OleDbParameter("Original_LastName", System.Data.OleDb.OleDbType.VarWChar, 20, System.Data.ParameterDirection.Input, False, CType(0, Byte), CType(0, Byte), "LastName", System.Data.DataRowVersion.Original, Nothing))
        '
        'OleDbConnection1
        '
        Me.OleDbConnection1.ConnectionString = "Integrated Security=SSPI;Packet Size=4096;Data Source=""LEETSCHA-PD3ZUL\LEE"";Tag w" & _
        "ith column collation when possible=False;Initial Catalog=Northwind;Use Procedure" & _
        " for Prepare=1;Auto Translate=True;Persist Security Info=False;Provider=""SQLOLED" & _
        "B.1"";Workstation ID=""LEETSCHA-PD3ZUL"";Use Encryption for Data=False"
        '
        'OleDbCommand1
        '
        Me.OleDbCommand1.CommandText = "SELECT EmployeeID, LastName, FirstName FROM Employees"
        Me.OleDbCommand1.Connection = Me.OleDbConnection1
        '
        'Button1
        '
        Me.Button1.Location = New System.Drawing.Point(96, 208)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(104, 32)
        Me.Button1.TabIndex = 1
        Me.Button1.Text = "显示读取的数据"
        '
        'RichTextBox1
        '
        Me.RichTextBox1.Font = New System.Drawing.Font("Microsoft Sans Serif", 9.75!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.RichTextBox1.Location = New System.Drawing.Point(8, 16)
        Me.RichTextBox1.Name = "RichTextBox1"
        Me.RichTextBox1.Size = New System.Drawing.Size(272, 176)
        Me.RichTextBox1.TabIndex = 2
        Me.RichTextBox1.Text = ""
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 266)
        Me.Controls.Add(Me.RichTextBox1)
        Me.Controls.Add(Me.Button1)
        Me.Name = "Form1"
        Me.Text = "Command和DataReader类的使用"
        Me.ResumeLayout(False)

    End Sub

#End Region

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        OleDbCommand1.Connection.Open()
        Dim str As System.Data.OleDb.OleDbDataReader = OleDbCommand1.ExecuteReader
        While str.Read
            RichTextBox1.Text = RichTextBox1.Text & str.Item("EmployeeID") & "号雇工的姓名是" & str.Item("Firstname") & " " & str.Item("LastName") + Chr(13) + Chr(10)
        End While
        str.Close()
        OleDbCommand1.Connection.Close()
    End Sub
End Class