Pls suggest me how to solve the problem...<< :)

[NannMaw]

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Server Error in '/WebSite1' Application.
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Invalid postback or callback argument. Event validation is enabled using <pages enableEventVali dation="true"/> in configuration or <%@ Page EnableEventVali dation="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 ClientScriptMan ager.RegisterFo rEventValidatio n 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.Argument Exception: Invalid postback or callback argument. Event validation is enabled using <pages enableEventVali dation="true"/> in configuration or <%@ Page EnableEventVali dation="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 ClientScriptMan ager.RegisterFo rEventValidatio n 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:


[ArgumentExcepti on: Invalid postback or callback argument. Event validation is enabled using <pages enableEventVali dation="true"/> in configuration or <%@ Page EnableEventVali dation="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 ClientScriptMan ager.RegisterFo rEventValidatio n method in order to register the postback or callback data for validation.]
System.Web.UI.C lientScriptMana ger.ValidateEve nt(String uniqueId, String argument) +358
System.Web.UI.C ontrol.Validate Event(String uniqueID, String eventArgument) +108
System.Web.UI.W ebControls.Drop DownList.LoadPo stData(String postDataKey, NameValueCollec tion postCollection) +52
System.Web.UI.W ebControls.Drop DownList.System .Web.UI.IPostBa ckDataHandler.L oadPostData(Str ing postDataKey, NameValueCollec tion postCollection) +11
System.Web.UI.P age.ProcessPost Data(NameValueC ollection postData, Boolean fBeforeLoad) +381
System.Web.UI.P age.ProcessRequ estMain(Boolean includeStagesBe foreAsyncPoint, Boolean includeStagesAf terAsyncPoint) +2965


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Hi, I got this error when I run my page on IE browser. I got no errors with FireFox .If there is anything to solve this problem, let me know.
Thanks.

[Plater]

You could turn off event validation like it says?
All it's doing is trying to make sure there are no postbacks that don't come specifically from aspnet controls.

[NannMaw]

You could turn off event validation like it says?
All it's doing is trying to make sure there are no postbacks that don't come specifically from aspnet controls.

Hi,Plater, I add "EnableEventVal idation="true" in Page directive. Then the error changes to :
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Server Error in '/WebSite1' Application.
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Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.
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.Web.Http Exception: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

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I wonder why its is ok when I run on FireFox.I got the errors when running IE browser.

Thanks 4 ur help.