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>
