上传图片到数据库，读取数据库中图片并显示(C#)

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from:http://blog.csdn.net/bfcady/article/details/2622701

思路：建立流对象，将上传图片临时保存到byte数组中，再用SQL语句将其保存到数据库中

说明：以下程序一切从简，实际用应用中应注意使用try等语句

创建表ImageStore，表结构如下图

主页面HTML如下

[html] view plain copy

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>图片上传</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:FileUpload ID="fuImage" runat="server" />
</div>
<div>
<asp:Button ID="btnUpload" runat="server" Text="上传图片" OnClick="btnUpload_Click" />
</div>
<div>
输入图片的ID：<asp:TextBox ID="txtImageID" runat="server"></asp:TextBox>
</div>
<div>
<asp:Button ID="btnSubmit" runat="server" Text="显示图片"
onclick="btnSubmit_Click" />
</div>
<div>
<asp:Image ID="Image1" runat="server" />
</div>
</form>
</body>
</html>

主页面后台代码

[csharp] view plain copy

using System;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.IO;
using System.Data.SqlClient;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btnUpload_Click(object sender, EventArgs e)
{
int imageLength = fuImage.PostedFile.ContentLength;//取得图片大小，以字节为单位
byte[] imageByteArray = new byte[imageLength]; //图片将临时存储在Byte(二进制)数组
Stream imageStream = fuImage.PostedFile.InputStream;//建立流对象
imageStream.Read(imageByteArray, 0, imageLength);//将图片读取到imageByteArray数组中，其中0为起始位置，imageLength为要读取的长度
//以下为数据库连接
SqlConnection sqlconn = new SqlConnection("server=(local);database=a0522183734;uid=a0522183734;pwd=bfcady");
string sql = "insert imageStore(ImageData,ImageContentType,ImageDescription,ImageSize) values(@Image,@ContentType,@ImageDescription, @ImageSize)";
SqlCommand sqlcom = new SqlCommand(sql, sqlconn);
sqlcom.Parameters.AddWithValue("@Image", imageByteArray);
sqlcom.Parameters.AddWithValue("@ContentType", Path.GetExtension(fuImage.PostedFile.FileName));//取得文件扩展名
//取得文件名，不包含扩展名，实际应用中作为图片描述用
sqlcom.Parameters.AddWithValue("@ImageDescription", Path.GetFileNameWithoutExtension(fuImage.PostedFile.FileName));
sqlcom.Parameters.AddWithValue("@ImageSize", imageLength);
sqlconn.Open();
sqlcom.ExecuteNonQuery();
sqlconn.Close();
}
protected void btnSubmit_Click(object sender, EventArgs e)
{
//改变图片的URL
Image1.ImageUrl = "ReadImage.ashx?imgID=" + txtImageID.Text;
}
}

创建一般处理程序ReadImage.ashx，读取图片

[csharp] view plain copy
1. <%@ WebHandler Language="C#" Class="ReadImage" %>
5. using System;
7. using System.Web;
9. using System.Data.SqlClient;
13. public class ReadImage : IHttpHandler {
17. public void ProcessRequest (HttpContext context) {
19. string imgID = context.Request.QueryString["imgID"].ToString();
21. SqlConnection sqlconn = new SqlConnection("server=(local);database=a0522183734;uid=a0522183734;pwd=bfcady");
23. string sql = "select * from ImageStore where ImageID=" + imgID;
25. SqlCommand sqlcom = new SqlCommand(sql, sqlconn);
27. sqlconn.Open();
29. SqlDataReader sqldr = sqlcom.ExecuteReader();
31. if (sqldr.Read())//移到第一条记录,如果第一条记录不为空
33. {
35. context.Response.ContentType = (string)sqldr["ImageContentType"];//设置输出类型
37. context.Response.OutputStream.Write((byte[])sqldr["ImageData"], 0, (int)sqldr["ImageSize"]);
39. context.Response.End();
41. }
43. sqlconn.Close();
45. }
49. public bool IsReusable {
51. get {
53. return false;
55. }
57. }
59. }