确定 ASP.NET AJAX 功能是否可用 AJAX是否安装

Private static readonly object ReflectionLock = new object();
Lock (ReflectionLock)
{
Type scriptManagerType =
Type.GetType(
"System.Web.UI.ScriptManager, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35",
false);
if (scriptManagerType != null)
// ASP.NET AJAX is installed.
else
// ASP.NET AJAX is not installed.

检查是否已为单个页启用 AJAX 功能
ScriptManager sm = ScriptManager.GetCurrent(Page)
if (sm == null)
{
// ASP.NET AJAX functionality is not enabled for the page.
}
else
{
// AJAX functionality is enabled for the page.
}

来自：http://msdn.microsoft.com/zh-cn/library/bb907614.aspx
同样，可以通过此方法，对其它的组件进行判断，如ActiveReport的判断  "DataDynamics.ActiveReports.Web.Handlers.CompiledReportHandler, ActiveReports.Web, Version=5.1.0.158, Culture=neutral, PublicKeyToken=cc4967777c49a3ff",
这个信息是从WebConfig文件中得到的。（不安装时会报错。查看相应的错误语句）
 <add path="Reserved.ReportViewerWebControl.axd" verb="*" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" validate="false" />
      <add verb="*" path="*.rpx" type="DataDynamics.ActiveReports.Web.Handlers.RpxHandler, ActiveReports.Web, Version=5.1.0.158, Culture=neutral, PublicKeyToken=cc4967777c49a3ff" />