使用SWFUpload实现无刷新上传图片_实用技巧_

 /// 
 /// 缩略图 /// 
 public class Thumbnail { public Thumbnail(string id, byte[] data) { this.ID = id; this.Data = data; } private string id; /// 
 /// 图片id /// 
 public string ID { get { return this.id; } set { this.id = value; } } private byte[] thumbnail_data; /// 
 /// 图片的二进制数据 /// 
 public byte[] Data { get { return this.thumbnail_data; } set { this.thumbnail_data = value; } } private string contentType; /// 
 /// 图片对应的MIME类型 /// 
 public string ContentType { get { return contentType; } set { contentType = value; } } } 

Upload Images Demo

 /// 
 /// 图片上传处理 /// 
 public class ImageUploadHandler : IHttpHandler, IRequiresSessionState { /// 
 /// 记录日志 logger /// 
 private static Common.LogHelper logger = new Common.LogHelper(typeof(ImageUploadHandler)); public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; System.Drawing.Image thumbnail_image = null; System.Drawing.Image original_image = null; System.Drawing.Bitmap final_image = null; System.Drawing.Graphics graphic = null; MemoryStream ms = null; try { //验证用户是否登录，是否有权限上传 if (context.Session["User"]==null) { context.Response.Write("没有上传图片的权限！"); context.Response.End(); return; } //获取上传文件 HttpPostedFile image_upload = context.Request.Files["Filedata"]; //获取文件扩展名 string fileExt = System.IO.Path.GetExtension(image_upload.FileName).ToLower(); //验证文件扩展名是否符合要求，是否是允许的图片格式 if (fileExt!=".jpg"&&fileExt!=".png") { return; } //当前时间字符串 string timeString = DateTime.Now.ToString("yyyyMMddHHmmssfff"); //图片保存虚拟路径构建 string path = "/Upload/"+timeString + fileExt; //保存到Session 变量中 context.Session["imgPath"] = path; //获取、构建要上传文件的物理路径 string serverPath = context.Server.MapPath("~/"+path); //保存图片到服务器 image_upload.SaveAs(serverPath); //记录日志 logger.Debug("图片上传成功！"); #region 生成缩略图 // 获取上传图片的文件流 original_image = System.Drawing.Image.FromStream(image_upload.InputStream); // 根据原图计算缩略图的宽度和高度，及缩放比例等~~ int width = original_image.Width; int height = original_image.Height; int target_width = 100; int target_height = 100; int new_width, new_height; float target_ratio = (float)target_width / (float)target_height; float image_ratio = (float)width / (float)height; if (target_ratio > image_ratio) { new_height = target_height; new_width = (int)Math.Floor(image_ratio * (float)target_height); } else { new_height = (int)Math.Floor((float)target_width / image_ratio); new_width = target_width; } new_width = new_width > target_width ? target_width : new_width; new_height = new_height > target_height ? target_height : new_height; //创建缩略图 final_image = new System.Drawing.Bitmap(target_width, target_height); graphic = System.Drawing.Graphics.FromImage(final_image); graphic.FillRectangle(new System.Drawing.SolidBrush(System.Drawing.Color.Black), new System.Drawing.Rectangle(0, 0, target_width, target_height)); int paste_x = (target_width - new_width) / 2; int paste_y = (target_height - new_height) / 2; graphic.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic; /* new way */ //graphic.DrawImage(thumbnail_image, paste_x, paste_y, new_width, new_height); graphic.DrawImage(original_image, paste_x, paste_y, new_width, new_height); // Store the thumbnail in the session (Note: this is bad, it will take a lot of memory, but this is just a demo) ms = new MemoryStream(); //将缩略图保存到内存流中 final_image.Save(ms, System.Drawing.Imaging.ImageFormat.Png); #endregion //建立 Thumbnail对象 Thumbnail thumb = new Thumbnail(timeString, ms.GetBuffer()); //保存缩略图到Session 中，也可以保存成文件，保存为图片 context.Session["file_info"] = thumb; //操作成功，返回HTTP状态码设置为 200 context.Response.StatusCode = 200; //输出缩略图的id，在生成缩略图时要用到 context.Response.Write(thumb.ID); } catch(Exception ex) { // 出现异常，返回 500，服务器内部错误 context.Response.StatusCode = 500; //记录错误日志 logger.Error(ex); } finally { // 释放资源 if (final_image != null) final_image.Dispose(); if (graphic != null) graphic.Dispose(); if (original_image != null) original_image.Dispose(); if (thumbnail_image != null) thumbnail_image.Dispose(); if (ms != null) ms.Close(); context.Response.End(); } } public bool IsReusable { get { return false; } } } 

 /// 
 /// 获取缩略图 /// 
 public class GetThumbHandler : IHttpHandler, IRequiresSessionState { public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; //获取缩略图id string id = context.Request.QueryString["id"]; //id为空则返回错误 if (String.IsNullOrEmpty(id)) { context.Response.StatusCode = 404; context.Response.Write("Not Found"); context.Response.End(); return; } //从Session中获取缩略图文件 Thumbnail thumb= context.Session["file_info"] as Thumbnail; //判断id是否一致 if (thumb.ID == id) { //重新设置响应MIME 类型 context.Response.ContentType = "image/png"; //输出二进制流信息 context.Response.BinaryWrite(thumb.Data); //截止输出 context.Response.End(); return; } //没有找到相应图片，返回404 context.Response.StatusCode = 404; context.Response.Write("Not Found"); context.Response.End(); } public bool IsReusable { get { return false; } } } 

 function fileQueueError(file, errorCode, message) { try { var imageName = "error.gif"; var errorName = ""; if (errorCode == SWFUpload.errorCode_QUEUE_LIMIT_EXCEEDED) { errorName = "上传文件过多！"; } if (errorName != "") { alert(errorName); return; } switch (errorCode) { case SWFUpload.QUEUE_ERROR.ZERO_BYTE_FILE: imageName = "zerobyte.gif"; break; case SWFUpload.QUEUE_ERROR.FILE_EXCEEDS_SIZE_LIMIT: imageName = "toobig.gif"; break; case SWFUpload.QUEUE_ERROR.ZERO_BYTE_FILE: case SWFUpload.QUEUE_ERROR.INVALID_FILETYPE: default: alert(message); break; } //添加图片，注意路径 addI
                
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