VB.NET操作 SQL SERVER的 二进制数据

在VB时期, 向SQL SERVER 中插入二进制数据, 是通过 ADODB.STREAM 实现, 在.NET中, 对 “流”格式的操作更加强大而简单,本篇演示向SQL SERVER 中插入数据并读出的功能.






在窗体上添加一个 OPENFILEDIALOG 控件, 两个PICTUREBOX, 代码如下:
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    Imports System.IO
Public Class Form1
    Inherits System.Windows.Forms.Form

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        Me.Dispose(True)
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If ofdPic.ShowDialog = DialogResult.OK Then
            pbPreview.Image = Image.FromFile(ofdPic.FileName)
        End If
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        If pbPreview.Image Is Nothing Then
            MsgBox("请先选择图片", MsgBoxStyle.Exclamation)
            Exit Sub
        End If
        Dim fs As FileStream = New FileStream(ofdPic.FileName, FileMode.Open, FileAccess.Read)
        Dim bt(fs.Length) As Byte
        fs.Read(bt, 0, fs.Length)
        fs.Close()
        fs = Nothing
        Dim sqlConn As SqlClient.SqlConnection = New SqlClient.SqlConnection("Server=(local);User Id=sa;Password=123;Database=pubs")
        sqlConn.Open()
        Dim sqlCmd As New SqlClient.SqlCommand("sp_InsertImage", sqlConn)
        sqlCmd.CommandType = CommandType.StoredProcedure
        sqlCmd.Parameters.Add("@img", SqlDbType.Image).Value = bt
        sqlCmd.ExecuteNonQuery()
        sqlCmd = Nothing
        sqlConn.Close()
        sqlConn = Nothing
        MsgBox("图片插入成功", MsgBoxStyle.Information)
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Dim sqlConn As SqlClient.SqlConnection = New SqlClient.SqlConnection("Server=(local);User Id=sa;Password=123;Database=pubs")
        sqlConn.Open()
        Dim sqlCmd As New SqlClient.SqlCommand("SELECT img FROM test WHERE t_ID=3", sqlConn)
        sqlCmd.CommandType = CommandType.Text

        Dim bt() As Byte = sqlCmd.ExecuteScalar()
        If Not bt Is Nothing Then
            If bt.Length > 0 Then
                Dim fs As MemoryStream = New MemoryStream(bt)
                pbReview.Image = Image.FromStream(fs)
                'fs.Close
                'fs = Nothing
                '可以自己试着将上面两句的注释去掉, 看有什么效果 ^_^
            Else
                MsgBox("无图片")
            End If
        Else
            MsgBox("无数据")
        End If

        sqlCmd = Nothing
        sqlConn.Close()
        sqlConn = Nothing
    End Sub
End Class
-----------------------------------------------------------------------------
数据库部分:
----------------
use pubs
go
Create Table test(t_ID int identity(1,1), img image)
go
Create Procedure sp_InsertImage
@img image
AS
Insert Into test (img) Values (@img)
go

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