图片在xml和数据库的存储和在web页的显示

一种是用字节数组表示二进制数据

<% @ Page Language = " C# "   %>
<% @ Import Namespace = " System.Xml "   %>
<% @ Import Namespace = " System.IO "   %>
<% @ Import Namespace = " System.Xml.XPath "   %>

< script runat = " server " >
     void  Page_Load( object  sender, EventArgs e)
     {        
        
        string xmlFilePath = @"C:\Employees.xml";
        string imageFileName = @"C:\Employee.jpg";
        try
        {
            using (XmlWriter writer = XmlWriter.Create(xmlFilePath))
            {
                //Start writing the XML document
                writer.WriteStartDocument(false);
                writer.WriteStartElement("employee");
                writer.WriteAttributeString("id", "1");
                writer.WriteStartElement("image");
                writer.WriteAttributeString("fileName", imageFileName);
                //Get the size of the file
                FileInfo fi = new FileInfo(imageFileName);
                int size = (int)fi.Length;
                //Read the JPEG file
                byte[] imgBytes = new byte[size];
                FileStream stream = new FileStream(imageFileName, FileMode.Open);
                BinaryReader reader = new BinaryReader(stream);
                imgBytes = reader.ReadBytes(size);
                reader.Close();
                //Write the JPEG data
                writer.WriteBinHex(imgBytes, 0, size);
                writer.WriteEndElement();
                writer.WriteEndElement();
                writer.WriteEndDocument();
                //flush the object and write the XML data to the file
                writer.Flush();
                lblResult.Text = "File is written successfully";
            }  
        }       
        catch (Exception ex)
        {
            lblResult.Text = "An Exception occurred: " + ex.Message;
        }        
    }

</ script >

< html xmlns = " http://www.w3.org/1999/xhtml "   >
< head runat = " server " >
     < title > Writing Images  using  XmlWriter </ title >
</ head >
< body >
     < form id = " form1 "  runat = " server " >
     < div >
         < asp:label id = " lblResult "  runat = " server "   />
     </ div >
     </ form >
</ body >
</ html >

读取显示

System.Xml.XPath.XPathDocument xdoc  =   new  XPathDocument(xmlFilePath);
            XPathNavigator xNav  =  xdoc.CreateNavigator();  
            XPathNodeIterator nodes  =  xNav.Select( " employee/image " );
             string  file  =   string .Empty;
             while (nodes.MoveNext())
             {
                file = nodes.Current.Value;
            }
             int  size  =  System.Text.Encoding.Default.GetByteCount(file);
            
            XmlReader xmlRead  =  XmlReader.Create(xmlFilePath);
             while (xmlRead.Read())
             {
                if(xmlRead.NodeType == XmlNodeType.Element && xmlRead.Name == "image")
                {
                    
                    byte[] bb = new byte[size];
                    xmlRead.ReadElementContentAsBinHex(bb, 0, size);
                    Response.BinaryWrite(bb);
                }
            }

第二种是 FileUpload上传图片

<% @ Page Language = " C# "   %>

<% @ Import Namespace = " System.Data.SqlClient "   %>

< script runat = " server " >
   string  CanUploadExt  =   " |.jpg|.gif|.bmp|.png|.jpeg| " ;
   protected   void  Page_Load( object  sender, EventArgs e)
   {
    if (!Page.IsPostBack)
    {
      string ConnectionString = "Data Source=.;Initial Catalog=pubs;User Id=sa;Password=;";
      SqlConnection cn = new SqlConnection(ConnectionString);
      string sql = "select id,Title from UserList Order By id DESC";
      cn.Open();
      SqlCommand cmd = new SqlCommand(sql, cn);
      GridView1.DataSource = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
      GridView1.DataBind();
      cn.Close();
      cn.Dispose();
    }
  }

   protected   void  Button1_Click( object  sender, EventArgs e)
   {
    if (FileUpload1.HasFile)
    {
      string FileExt = System.IO.Path.GetExtension(FileUpload1.FileName);
      if (FileExt.Length < 1)
      {
        return;
      }
      FileExt = FileExt.ToLower();
      if (CanUploadExt.IndexOf("|" + FileExt + "|") == -1)
      {
        return;
      }
      string ContentType = FileUpload1.PostedFile.ContentType;
      byte[] fileData = FileUpload1.FileBytes;
      string sql;
      sql = "INSERT INTO UserList (Title,ContentType,Photo) Values(@Title,@ContentType,@Photo)";
      string ConnectionString = "Data Source=.;Initial Catalog=pubs;User Id=sa;Password=;";
      SqlConnection cn = new SqlConnection(ConnectionString);
      cn.Open();
      SqlCommand cmd = new SqlCommand(sql, cn);
      cmd.Parameters.Add("@Title", System.Data.SqlDbType.NVarChar);
      cmd.Parameters.Add("@ContentType", System.Data.SqlDbType.VarChar);
      cmd.Parameters.Add("@Photo", System.Data.SqlDbType.Image);
      cmd.Parameters["@Title"].Value = TextBox1.Text;
      cmd.Parameters["@ContentType"].Value = ContentType;
      cmd.Parameters["@Photo"].Value = fileData;
      cmd.ExecuteNonQuery();
      cn.Close();
      cn.Dispose();
    }
    Response.Redirect(Request.UrlReferrer.ToString());
  }
</ script >

< html xmlns = " http://www.w3.org/1999/xhtml " >
< head runat = " server " >
   < title > FileUpload 服务器控件 </ title >

   < script type = " text/javascript "  language = " javascript " >
  var CanUploadExt  =   " <%=CanUploadExt %> "
  function CheckExt()
   {
    var oFile = document.getElementById('<%=FileUpload1.ClientID %>')
    var ext = oFile.value.substr(oFile.value.lastIndexOf("."))
    if(ext.length < 1)
    {
      alert("请选择图像文件。")
      return false
    }
    else
    {
      ext = ext.toLowerCase();
      if(CanUploadExt.indexOf("|" + ext + "|") == -1)
      {
        alert("请选择图像文件:" + CanUploadExt)
        return false
      }
    }
    return true
  }
   </ script >

</ head >
< body >
   < form id = " form1 "  runat = " server " >
     < asp:GridView ID = " GridView1 "  runat = " server "  AutoGenerateColumns = " false " >
       < Columns >
         < asp:BoundField HeaderText = " 姓名 "  NullDisplayText = " 未输入 "  DataField = " Title "   />
         < asp:ImageField HeaderText = " 照片 "  DataImageUrlField = " id "
         DataImageUrlFormatString = " ShowImageCS.aspx?id={0} "  NullImageUrl = " ~/images/none.gif " >
         </ asp:ImageField >
       </ Columns >
     </ asp:GridView >
    姓名： < asp:TextBox ID = " TextBox1 "  runat = " server " ></ asp:TextBox >
     < asp:FileUpload ID = " FileUpload1 "  runat = " server "   />
     < asp:Button ID = " Button1 "  runat = " server "  OnClick = " Button1_Click "  OnClientClick = " return CheckExt() "
      Text = " 上传 "   />
   </ form >
</ body >
</ html >

显示

<% @ Page Language = " C# "   %>
<% @ Import Namespace = " System.Data.SqlClient "   %>
< script runat = " server " >
   protected   void  Page_Load( object  sender, EventArgs e)
   {
    Response.Clear();
    int IsOkID;
    bool strImageID = Int32.TryParse(Request.QueryString["id"], out IsOkID);
    if (!strImageID)
    {
      Response.ContentType = "image/gif";
      Response.WriteFile("~/images/none.gif");
      return;
    }
    string ConnectionString = "Data Source=.;Initial Catalog=pubs;User Id=sa;Password=;";
    SqlConnection cn = new SqlConnection(ConnectionString);
    string sql = "select ContentType,Photo from UserList Where id=@id";
    cn.Open();
    SqlCommand cmd = new SqlCommand(sql, cn);
    cmd.Parameters.Add("@id", System.Data.SqlDbType.Int, 4);
    cmd.Parameters["@id"].Value = IsOkID;
    SqlDataReader myDataReader;
    myDataReader = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
    if (myDataReader.Read())
    {
      Response.ContentType = myDataReader["ContentType"].ToString();
      Response.BinaryWrite((byte[])myDataReader["Photo"]);
    }
    else
    {
      Response.ContentType = "image/gif";
      Response.WriteFile("~/images/none.gif");
    }
    cn.Close();
    cn.Dispose();
    Response.End();
  }
</ script >