写入和读取图片的方法技巧
作者：木子 http://blog.csdn.net/derny/
首先要创建一个表包含自段image 和 type 类型各自为image 和 vnancharWebForm1.aspx
<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false" Inherits="ReadAndWritePicFromDB.WebForm1" %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" > <HTML> <HEAD> <title>WebForm1</title> <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1"> <meta name="CODE_LANGUAGE" Content="C#"> <meta name="vs_defaultClientScript" content="JavaScript"> <meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5"> </HEAD> <body MS_POSITIONING="GridLayout"> <form id="Form1" method="post" runat="server"> <FONT face="宋体"><INPUT id="File1" style="Z-INDEX: 101; LEFT: 112px; POSITION: absolute; TOP: 88px" type="file" name="File1" runat="server"></FONT> <asp:Button id="Button1" style="Z-INDEX: 102; LEFT: 400px; POSITION: absolute; TOP: 88px" runat="server" Text="Write" Width="104px"></asp:Button> <asp:Button id="Button2" style="Z-INDEX: 103; LEFT: 552px; POSITION: absolute; TOP: 88px" runat="server" Text="Read" Width="105px"></asp:Button> </form> </body> </HTML>
WebForm1.aspx.cs
using System;
using System.Collections; using System.ComponentModel; using System.Data; using System.Drawing; using System.Web; using System.Web.SessionState; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.HtmlControls; using System.IO; using System.Data.SqlClient;namespace ReadAndWritePicFromDB
{ /// <summary> /// WebForm1 的摘要说明。 /// </summary> public class WebForm1 : System.Web.UI.Page { protected System.Web.UI.HtmlControls.HtmlInputFile File1; protected System.Web.UI.WebControls.Button Button1; private string fileName = "" ; protected System.Web.UI.WebControls.Button Button2; private static SqlConnection conn = null; private void Page_Load(object sender, System.EventArgs e) { // 在此处放置用户代码以初始化页面 ConnectDB(); }//得到文件名
private string GetFile() { HttpPostedFile file = File1.PostedFile; fileName = file.FileName;return fileName;
}//读取文件内容
private byte[] ReadFile() { FileStream file = File.OpenRead(GetFile()); byte[] content = new byte[file.Length]; file.Read(content,0,content.Length); file.Close(); return content; }//连接数据库
private void ConnectDB() { string connStr = "Initial Catalog=;Data Source=;User ID=;Password=;"; conn = new SqlConnection(connStr); conn.Open(); }//写入图片到数据库中
private void WriteImage() { SqlCommand comm = conn.CreateCommand(); comm.CommandText = "insert into images(image,type) values(@image,@type)"; comm.CommandType = CommandType.Text; SqlParameter param = comm.Parameters.Add("@image",SqlDbType.Image); param.Value = ReadFile(); param = comm.Parameters.Add("@type",SqlDbType.NVarChar); param.Value = GetContentType(new FileInfo(fileName).Extension.Remove(0,1));if(comm.ExecuteNonQuery() == 1)
Response.Write("Successful"); else Response.Write("Fail"); conn.Close(); }//获取图片的后缀名
private string GetContentType(string extension) { string type = "";if(extension.Equals("jpg") || extension.Equals("JPG"))
type = "jpeg"; else type = extension;return "image/"+type;
}//从数据库中读取图片
private void ReadImage() { SqlCommand comm = conn.CreateCommand(); comm.CommandText = "select image,type from images"; comm.CommandType = CommandType.Text;SqlDataReader reader = comm.ExecuteReader();
while(reader.Read()) { Response.ContentType = reader["type"].ToString();//读写类型 一定要设置 否则浏览器会当作文本输出 Response.BinaryWrite((byte[])reader["image"]);//图片数据 }Response.Write("Successful");
Response.End();conn.Close();
} #region Web 窗体设计器生成的代码 override protected void OnInit(EventArgs e) { // // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。 // InitializeComponent(); base.OnInit(e); } /// <summary> /// 设计器支持所需的方法 - 不要使用代码编辑器修改 /// 此方法的内容。 /// </summary> private void InitializeComponent() { this.Button1.Click += new System.EventHandler(this.Button1_Click); this.Button2.Click += new System.EventHandler(this.Button2_Click); this.Load += new System.EventHandler(this.Page_Load);}
#endregionprivate void Button1_Click(object sender, System.EventArgs e)
{ WriteImage(); }private void Button2_Click(object sender, System.EventArgs e)
{ try { ReadImage(); } catch(Exception ep) { conn.Close(); Response.End(); } } } }