ASP.NET2.0图片格式转换
作者：清清月儿
主页：http://blog.csdn.net/21aspnet/ 时间：2007.4.20
说明：本文实现了 图片格式随意转换（下拉框选择）； 点击FileUpload立即显示图片（Js实现）的技巧；
第一步：打开页面
第二步：选择一副Jpg格式的图片
第三步：转换为GIF格式，明显看出图片画质降低。
后台代码： using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.IO; using System.Drawing; public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void Button1_Click(object sender, EventArgs e) { string filepath = FileUpload1.PostedFile.FileName; string filename = filepath.Substring(filepath.LastIndexOf("//") 1); string serverpath = Server.MapPath("images/") System.DateTime.Now.ToString("yyy-MM-dd-hh-mm-ss") Session.SessionID filename;
if (DropDownList1.SelectedValue == "GIF") { ConvertImage(FileUpload1.PostedFile.FileName, System.Drawing.Imaging.ImageFormat.Gif, serverpath ".gif"); } else if(DropDownList1.SelectedValue == "Jpeg") { ConvertImage(FileUpload1.PostedFile.FileName, System.Drawing.Imaging.ImageFormat.Jpeg, serverpath ".jpg"); } else if(DropDownList1.SelectedValue == "Bmp") { ConvertImage(FileUpload1.PostedFile.FileName, System.Drawing.Imaging.ImageFormat.Bmp, serverpath ".bmp"); } else { //清清月儿留给大家http://blog.csdn.net/21aspnet } }
public void ConvertImage(string Filename, System.Drawing.Imaging.ImageFormat DesiredFormat, string NewFilename) { try { System.Drawing.Image imgFile = System.Drawing.Image.FromFile(Filename); imgFile.Save(NewFilename, DesiredFormat); Image1.ImageUrl = NewFilename; Label1.Text = "转换成功，生成" NewFilename "，如下所示。"; TextBox1.Text = "1";//开始为0，转换后为1 } catch (Exception ex) { Response.Write(ex); } }
}
前台代码： <%@ 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>图片格式转换</title> <script language="javascript"> function show_img()//实现选择图片后立即显示给客户 { if(document.all.TextBox1.value=="0"){//开始为0，转换后为1 document.all.Image1.src=document.all.FileUpload1.value; } else if(document.all.TextBox1.value=="1") { } } </script> </head> <body> <form id="form1" runat="server"> <div> <table> <tr> <td style="width: 124px"> <asp:FileUpload ID="FileUpload1" runat="server" οnmοuseοver="show_img()" Width="349px"/> </td> <td style="width: 100px"> 格式<asp:DropDownList ID="DropDownList1" runat="server"> <asp:ListItem>GIF</asp:ListItem> <asp:ListItem>Jpeg</asp:ListItem> <asp:ListItem>Bmp</asp:ListItem> <asp:ListItem>Png</asp:ListItem> <asp:ListItem>Ico</asp:ListItem> </asp:DropDownList> </td> <td style="width: 100px"> <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="转换" /></td> <td style="width: 100px"> <asp:TextBox ID="TextBox1" runat="server">0</asp:TextBox> </td> </tr> <tr> <td colspan="4"> <asp:Label ID="Label1" runat="server"></asp:Label></td> </tr> <tr> <td style="height: 26px;" colspan="4"> <asp:Image ID="Image1" runat="server" /></td> </tr> </table> </div> </form> </body> </html>
