代码笔记 | Echart显示或导出图片

来源：互联网发布：linux强制改语言编辑：程序博客网时间：2024/05/15 23:49

接收Echar生成的Base64数据，转换为图片或生成下载。

 <%@ WebHandler Language="C#" Class="ExportImg" %>using System;using System.Web;using System.Data;public class ExportImg : IHttpHandler{    public void ProcessRequest(HttpContext context)    {        try        {            string req = context.Request["imgdata"].ToString();            base64TOpic(context, req);        }        catch        {            context.Response.ContentType = "text/plain";            context.Response.Write("参数错误,请生成图片后再导出!!");        }    }    public void base64TOpic(HttpContext context, string req)    {        String[] url = req.Split(',');        String u = url[1];        byte[] buffer = Convert.FromBase64String(u);        System.IO.MemoryStream ms = new System.IO.MemoryStream(buffer);        //输出为文件下载        context.Response.ContentType = "application/octet-steam";        context.Response.AddHeader("Content-Disposition", "attachment;   filename=" + HttpUtility.UrlEncode("导出图片.png", System.Text.Encoding.UTF8));        //输出为文件下载        //输出为图片        //context.Response.ContentType = "image/png";        //输出为图片        //二进制流一次性输出        //context.Response.BinaryWrite(buffer);        //二进制流一次性输出        //二进制流分片输出        context.Response.Cache.SetCacheability(HttpCacheability.Public);        context.Response.BufferOutput = false;        const int buffersize = 1024 * 16;        byte[] Buffer = new byte[buffersize];        int count = ms.Read(Buffer, 0, buffersize);        while (count > 0)        {            context.Response.OutputStream.Write(Buffer, 0, count);            count = ms.Read(Buffer, 0, buffersize);        }        //二进制流分片输出        context.Response.Flush();        context.Response.End();    }    public bool IsReusable    {        get        {            return false;        }    }}

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