server|数据|数据库4、 声明类级的变量。找到设计期产生的代码部分，把下面的语句加到变量声明后面。什么？不知道变量声明在哪儿?不会吧！

Private fs As FileStream

Private ds As DataSet

Private conn As New SqlConnection("server=localhost;database=northwind;integrated security=true;")

Private currentpos As Integer = 9



5、 开始写代码了。首先是form_load

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load



btnOpen.Enabled = True

btnSave.Enabled = True

btnBack.Enabled = False

btnForward.Enabled = False

End Sub

6、 open按钮的点击事件代码：

Private Sub openbtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOpen.Click

Dim Opendlg As New OpenFileDialog

Opendlg.Title = "Select a picture file"

Opendlg.Filter = "(*.bmp)|*bmp|(*.jpg)|*.jpg"

Opendlg.ShowDialog()

lblPath.Text = Opendlg.FileName.ToString()

fs = New FileStream(Opendlg.FileName.ToString(), FileMode.Open, FileAccess.Read)

PictureBox1.Image = Image.FromFile(Opendlg.FileName.ToString())

End Sub

7、 save按钮的点击事件代码

Private Sub savebtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click

Dim sqlcomm As New SqlCommand

sqlcomm.CommandText = "INSERT INTO employees (lastname,firstname,photo) VALUES (lastname,firstname,photo)"

sqlcomm.Connection = conn

Dim Data(fs.Length) As Byte

fs.Read(Data, 0, Int(fs.Length))

Dim prm1 As New SqlParameter("lastname", txtLN.Text)

Dim prm2 As New SqlParameter("firstname", txtFN.Text)

Dim prm3 As New SqlParameter("photo", SqlDbType.VarBinary, Int(fs.Length), ParameterDirection.Input, False, 0, 0, "", DataRowVersion.Current, Data)

sqlcomm.Parameters.Add(prm1)

sqlcomm.Parameters.Add(prm2)

sqlcomm.Parameters.Add(prm3)

Try

conn.Open()

sqlcomm.ExecuteNonQuery() '执行插入语句

conn.Close()

fs.Close()

Catch ex As Exception

MsgBox(ex.Message)

End Try

End Sub

8、 选择view状态的事件代码

Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged

If CheckBox1.Checked = True Then

btnOpen.Enabled = False

btnSave.Enabled = False

btnBack.Enabled = True

btnForward.Enabled = True

currentpos = 9

Dim sqlcomm As New SqlCommand

sqlcomm.CommandText = "SELECT employeeId, photo FROM employees ORDER BY employeeId"

sqlcomm.Connection = conn

Dim da As New SqlDataAdapter(sqlcomm)

Try

conn.Open()

ds = New DataSet

da.Fill(ds, "employees")

conn.Close()

Catch sqlEx As SqlException

MsgBox(sqlEx.Message)

End Try



Dim data() As Byte = ds.Tables("employees").Rows(9)("photo")

Dim stmphoto As New MemoryStream(data)

PictureBox1.Image = Image.FromStream(stmphoto)

Else

btnOpen.Enabled = True

btnSave.Enabled = True

btnBack.Enabled = False

btnForward.Enabled = False

End If

End Sub

9、 “>>”按钮点击事件代码



Private Sub forward_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnForward.Click

If currentpos = ds.Tables("employees").Rows.Count - 1 Then

Return

Else

currentpos += 1

Dim data() As Byte

data = ds.Tables("employees").Rows(currentpos)("photo")

Dim stmphoto As New MemoryStream(data)

PictureBox1.Image = Image.FromStream(stmphoto)

End If

End Sub

10、 “<<”按钮点击事件代码

Private Sub back_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBack.Click

If currentpos = 9 Then

Return

Else

currentpos -= 1

End If



Dim Data() As Byte

Data = ds.Tables("employees").Rows(currentpos)("photo")

Dim stmPhoto As New MemoryStream(Data)

PictureBox1.Image = Image.FromStream(stmPhoto)

End Sub

11、 好了，可以运行看看了。