[英]read image using ashx doesn't work in asp.net
I am trying to use ashx to load an image from database . 我正在尝试使用ashx从数据库加载图像。
when i use this code the image is loaded successfully 当我使用此代码时,图像加载成功
<% <asp:Image ID="Image1" runat="server" ImageUrl='<%# Eval("Id", "~/Handler/CategoryHandler.ashx?catId={0}") %>' />
But when i use this code 但是当我使用这段代码
<%
foreach (ProductCategories VARIABLE in categoriesList)
{
Response.Write("<div class='wrapper-box'>" +
"<a href='product/product.aspx'>" +
"<img src='~/Handler/ProductHandler.ashx?Id="+VARIABLE.Id+"'/>" +
"<p>"+VARIABLE.CategoryName+"</p>" +
"</a>" +
"</div>");
}
%>
The image doesn't load .why the code doesn't work ? 图片未加载。为什么代码不起作用?
The ashx file is like this : ashx文件是这样的:
public void ProcessRequest(HttpContext context)
{
// Set up the response settings
context.Response.ContentType = "image/jpeg";
context.Response.Cache.SetCacheability(HttpCacheability.Public);
context.Response.BufferOutput = false;
// Setup the Size Parameter
ImageSize size;
switch (context.Request.QueryString["Size"])
{
case "S":
size = ImageSize.Small;
break;
case "L":
size = ImageSize.Large;
break;
default:
size = ImageSize.Small;
break;
}
// Setup the PhotoID Parameter
Stream stream;
if (context.Request.QueryString["Id"] != null && context.Request.QueryString["Id"] != "")
{
Int32 id = Convert.ToInt32(context.Request.QueryString["Id"]);
stream = Products.GetImageStream(id, size);
//context.Response.AddHeader("content-disposition", String.Format("attachement;filename=\"{0}\"", );
// Get the photo from the database, if nothing is returned, get the default "placeholder" photo
if (stream == null) return;
// Write image stream to the response stream
const int buffersize = 1024 * 16;
byte[] buffer = new byte[buffersize];
int count = stream.Read(buffer, 0, buffersize);
while (count > 0)
{
context.Response.OutputStream.Write(buffer, 0, count);
count = stream.Read(buffer, 0, buffersize);
}
}
}
The problem is that Response.Write
does not expand the ~
character to the base URL, so the URL of the image that is generated in the HTML of the page is similar to this: 问题是
Response.Write
不会将~
字符扩展为基本URL,因此在页面的HTML中生成的图像的URL与此类似:
<img src='~/Handler/ProductHandler.ashx?Id=123' />
In order to solve this, you have to expand the URL before you use it in Response.Write
: 为了解决这个问题,必须在使用
Response.Write
之前扩展URL:
<%
foreach (ProductCategories VARIABLE in categoriesList)
{
var imgUrl = ResolveUrl("~/Handler/ProductHandler.ashx?Id=" + VARIABLE.Id.ToString());
Response.Write("<div class='wrapper-box'>" +
"<a href='product/product.aspx'>" +
"<img src='" + imgUrl + "'/>" +
"<p>"+VARIABLE.CategoryName+"</p>" +
"</a>" +
"</div>");
}
%>
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