ASP.NET2.0 图片格式转换
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")
{