To use HTTPHandler with a Cache-based transfer method and a unique image ID to transfer C1WebChart to the client, complete the following steps:

1.   Place a C1WebChart control on a form. A Confirmation dialog box appears.

2.   Click Yes to add the HttpHandler to the web.config file. This configures the application to enable the C1WebChart's built-in HttpHandler.

The following entry is added to the Web.config file:

<configuration>

  <system.web>

    <httpHandlers>

      <add verb="*" path="c1chartimage.aspx"

         type="C1.Web.C1WebChart.ImageHttpHandler,C1.Web.C1WebChart.2"/>

    </httpHandlers>

  </system.web>

<configuration>

3.   Configure the data and appearance elements as desired.

4.   Set C1WebChart's properties to the following:

·      Set the ImageRenderMethod property to HttpHandler.

·      Set the ImageTransferMethod property to Cache.

·      Set the ImageIDGeneration property to Unique.

·      Set the ImageUri property to an empty string.

Run the program and notice the following:

The image tag created should look similar to:

<img id=_c1wc src='c1webchartimage.aspx?CacheID=91…93&Delete=T'/>

Because the ImageIDGeneration property is set to Unique, the CacheID attribute is unique for each rendering of the chart. It provides access to the following Cache entries:

91…93_ImageBytes (image)

91…93_Hash (hash code and image type)

The Delete=T attribute causes the cache entries to be deleted after the data is received by the HTTPHandler. This attribute is always invoked for Unique IDs.