动态影像使用通用处理器（从DB）

问题描述

我试图使用通用处理器来检索和显示存储在数据库中的图像。

但它只是不工作。香港专业教育学院试图verious低于code，但我似乎无法得到它的工作。

能否anyonne发现我在做什么错了，还是有一些建议？

 ＆LT;％@ WebHandler LANGUAGE =C＃类=IconsDb％GT;使用系统;
使用的System.Web;
使用System.Linq的;
使用System.Data.Entity的;公共类IconsDb：IHttpHandler的{    公共无效的ProcessRequest（HttpContext的背景下）{
        context.Response.ContentType =text / plain的;
        context.Response.Write（的Hello World）;
        INT32 iconId;        如果（context.Request.QueryString [ID]！= NULL）
            iconId = Convert.ToInt32（context.Request.QueryString [ID]）;
        其他
            抛出新的ArgumentException（没有指定的参数）;        context.Response.ContentType =图像/ GIF;
        //System.IO.Stream STRM = ShowEmpImage（iconId）;        变种DB =新UdINaturen.UdINaturenContext（）;        在db.subcategoryicons VAR =调用getIcon（从我
                       其中，i.id == iconId
                       选择i.p​​icture）.FirstOrDefault（）;
        反对IMG =调用getIcon;        System.IO.MemoryStream memStream =新System.IO.MemoryStream（（字节[]）Convert.FromBase64String（调用getIcon））;
        System.Drawing.Bitmap bitImage =新System.Drawing.Bitmap（（System.Drawing.Bitmap）System.Drawing.Image.FromStream（memStream））;
        字节[]缓冲= memStream.ToArray（）;
        context.Response.ContentType =图像/ GIF;
        //context.Response.OutputStream.Write(buffer，0，buffer.Length）;
        //context.Response.WriteFile（）;
        context.Response.BinaryWrite（缓冲液）;
        //context.Response.Flush（）;
    }    公共BOOL IsReusable {
        获得{
            返回true;
        }
    }}
 

解决方案

哇，好不好。不知道有多少是旧的code，什么应该被注释掉或W / E，但尝试这样的：

 公共无效的ProcessRequest（HttpContext的背景下）{
    INT iconId;    如果（string.IsNullOrEmpty（context.Request.QueryString [ID]）||！int.TryParse（context.Request.QueryString [ID]，出iconId））
        抛出新的ArgumentException（没有指定的参数）;    context.Response.ContentType =图像/ GIF;    变种DB =新UdINaturen.UdINaturenContext（）;    在db.subcategoryicons VAR =调用getIcon（从我
                   其中，i.id == iconId
                   选择i.p​​icture）.FirstOrDefault（）;
    字节[]缓冲=（字节[]）Convert.FromBase64String（调用getIcon）;    context.Response.ContentType =图像/ GIF;
    context.Response.BinaryWrite（缓冲液）;
    context.Response.Flush（）;
}
 

I'm trying to using a Generic Handler to retrieve and display images that are stored in a database.

But its just not working. Ive tried verious of the code below, but I cant seem to get it to work.

Can anyonne spot what I am doing wrong, or have some suggestions?

<%@ WebHandler Language="C#" Class="IconsDb" %>

using System;
using System.Web;
using System.Linq;
using System.Data.Entity;

public class IconsDb : IHttpHandler {

    public void ProcessRequest (HttpContext context) {
        context.Response.ContentType = "text/plain";
        context.Response.Write("Hello World");
        Int32 iconId;

        if (context.Request.QueryString["id"] != null)
            iconId = Convert.ToInt32(context.Request.QueryString["id"]);
        else
            throw new ArgumentException("No parameter specified");

        context.Response.ContentType = "image/gif";
        //System.IO.Stream strm = ShowEmpImage(iconId);

        var db = new UdINaturen.UdINaturenContext();

        var GetIcon = (from i in db.subcategoryicons
                       where i.id == iconId
                       select i.picture).FirstOrDefault();
        object img = GetIcon;

        System.IO.MemoryStream memStream= new System.IO.MemoryStream((byte[])Convert.FromBase64String(GetIcon));
        System.Drawing.Bitmap bitImage=new System.Drawing.Bitmap((System.Drawing.Bitmap)System.Drawing.Image.FromStream(memStream));


        byte[] buffer = memStream.ToArray();
        context.Response.ContentType = "image/gif";
        //context.Response.OutputStream.Write(buffer, 0, buffer.Length);
        //context.Response.WriteFile();
        context.Response.BinaryWrite(buffer);
        //context.Response.Flush();


    }





    public bool IsReusable {
        get {
            return true;
        }
    }

}

解决方案

wow, ok. Not sure how much of that is old code, what should be commented out or w/e but try something like this:

public void ProcessRequest (HttpContext context) {
    int iconId;

    if (string.IsNullOrEmpty(context.Request.QueryString["id"]) || !int.TryParse(context.Request.QueryString["id"], out iconId) )
        throw new ArgumentException("No parameter specified");

    context.Response.ContentType = "image/gif";

    var db = new UdINaturen.UdINaturenContext();

    var GetIcon = (from i in db.subcategoryicons
                   where i.id == iconId
                   select i.picture).FirstOrDefault();
    byte[] buffer = (byte[])Convert.FromBase64String(GetIcon);

    context.Response.ContentType = "image/gif";
    context.Response.BinaryWrite(buffer);
    context.Response.Flush();
}

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