asp.net – 无效的回发或回调参数.单击按钮时

我有一个包含各种控件的网页.其中两个是下拉列表.第一个下拉列表从page_load事件的xml文件中填充.这很好用.在第一个下拉列表中附加了一个级联下拉列表扩展器,每次更改第一个下拉列表中的选择时,都会调用Web服务.这也很好.在我的两个下拉列表下面,我有一个按钮,可以将页面发回.但是,当我在第二个下拉列表中进行选择并单击按钮时,我收到以下错误：

Server Error in ‘/’ Application.
Invalid postback or callback argument. Event validation is enabled using in configuration or <%@ Page EnableEventValidation=”true” %> in a page. For security purposes,this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected,use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ArgumentException: Invalid postback or callback argument. Event validation is enabled using in configuration or <%@ Page EnableEventValidation=”true” %> in a page. For security purposes,use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[ArgumentException: Invalid postback or callback argument. Event validation is enabled using in configuration or <%@ Page EnableEventValidation=”true” %> in a page. For security purposes,use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.]
System.Web.UI.ClientScriptManager.ValidateEvent(String uniqueId,String argument) +10945696
System.Web.UI.WebControls.DropDownList.LoadPostData(String postDataKey,NameValueCollection postCollection) +72
System.Web.UI.Page.ProcessPostData(NameValueCollection postData,Boolean fBeforeLoad) +507
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint,Boolean includeStagesAfterAsyncPoint) +2071

抱歉可怕的格式化.有关为什么抛出此错误以及如何防止它的任何建议？

谢谢,
本