AjaxControlToolkit Multiple Files Upload

Web Page:

 <ajaxToolkit:ToolkitScriptManager ID="ToolkitScriptManager_Settlement" runat="server">  
    </ajaxToolkit:ToolkitScriptManager>  
  <ajaxToolkit:AjaxFileUpload ID="AjaxFileUpload_Settlement"
    ThrobberID="myThrobber"
    ContextKeys="fred"
    AllowedFileTypes="xls,xlsx"
    MaximumNumberOfFiles="10"
    OnUploadComplete="OnClientUploadComplete"
    runat="server" />

Reference

Web.config

 <system.web>

  <httpHandlers>
      <!-- Using CombineCriptsHandler.axd as path of handler -->

      <add verb="*" path="CombineScriptsHandler.axd"

              type="AjaxControlToolkit.CombineScriptsHandler,

               AjaxControlToolkit" />
      <add verb="*" path="AjaxFileUploadHandler.axd"
        type="AjaxControlToolkit.AjaxFileUploadHandler,
          AjaxControlToolkit"/>
    </httpHandlers>

 </system.web>

system.webServer>
     <modules runAllManagedModulesForAllRequests="true" />
    <validation validateIntegratedModeConfiguration="false" />

    <handlers>

      <!-- Using CombineCriptsHandler as name of handler -->

      <add name="CombineScriptsHandler" verb="*"

                path="CombineScriptsHandler.axd"

          type="AjaxControlToolkit.CombineScriptsHandler,

         AjaxControlToolkit" />

    </handlers>
  </system.webServer>