If you work with web sites in a complex/multi server environment you might be familiar with this error and as the error message itself suggest, the first thing to check if the machineKey value which must be the same across all of the involved server.
Anyway every now and then it happens that you might get this same error even if you are not in a NBL/Cluter environment (Tess and Tom have blogged about this here, here and here) or if you are absolutely sure you have properly configured the machineKey value. So what else can lease you to this state?
If you want some quick background you have a look at my post here; basically we have the following (very raw) steps:
-
- Begin processing the new request
- Load the “old” state (ViewState and ControlState) received with the posted values
- Process the posted data (the actual form values) and raise the “change” events to change control state and do the real page work
- Save the new state (again, ViewState and ControlState)
- Send the result back to the client
It is important to note that if you dynamically add controls at runtime on your page (i.e. you do not only rely on the page markup to create your layout) it is vital that the controls are added always in the same order or the viewstate validation will fail and you’ll get the error.
Some debugging
We got a dump of the problem; unfortunately in SOS for .NET 2.0 we miss some commands we have in SOS for .NET 1.1, but even if with a bit more typing and digging we can get the same results. The next logical step is to have a look at the exceptions on the managed heap:
0:033> !dumpheap -type Exception -stat
------------------------------
Heap 0
total 2 objects
------------------------------
Heap 1
total 4 objects
------------------------------
Heap 2
total 0 objects
------------------------------
Heap 3
total 7 objects
------------------------------
Heap 4
total 9 objects
------------------------------
Heap 5
total 0 objects
------------------------------
Heap 6
total 0 objects
------------------------------
Heap 7
total 4 objects
------------------------------
total 26 objects
Statistics:
MT Count TotalSize Class Name
79103ca4 2 24 System.Text.DecoderExceptionFallback
79103c58 2 24 System.Text.EncoderExceptionFallback
502254bc 2 40 System.ServiceModel.Diagnostics.ExceptionUtility
790fe17c 1 72 System.ExecutionEngineException
790fe0e0 1 72 System.StackOverflowException
790fe044 1 72 System.OutOfMemoryException
6640ab48 1 104 System.Web.UI.ViewStateException
20f199b4 1 112 Microsoft.ReportingServices.Diagnostics.Utilities.InternalCatalogException
790fe284 2 144 System.Threading.ThreadAbortException
663dc0d4 2 168 System.Web.HttpException
79118794 11 352 System.UnhandledExceptionEventHandler
We have a ViewStateException so for sure it worth digging into it using the MetodTable:
0:033> !dumpheap -mt 6640ab48 ------------------------------ Heap 0 Address MT Size total 0 objects ------------------------------ Heap 1 Address MT Size 042c74dc 6640ab48 104 total 1 objects ------------------------------ Heap 2 Address MT Size total 0 objects ------------------------------ Heap 3 Address MT Size total 0 objects ------------------------------ Heap 4 Address MT Size total 0 objects ------------------------------ Heap 5 Address MT Size total 0 objects ------------------------------ Heap 6 Address MT Size total 0 objects ------------------------------ Heap 7 Address MT Size total 0 objects ------------------------------ total 1 objects Statistics: MT Count TotalSize Class Name 6640ab48 1 104 System.Web.UI.ViewStateException Total 1 objects 0:033> !do 042c74dc Name: System.Web.UI.ViewStateException MethodTable: 6640ab48 EEClass: 6640aad0 Size: 104(0x68) bytes (C:\WINDOWS\assembly\GAC_32\System.Web\2.0.0.0__b03f5f7f11d50a3a\System.Web.dll) Fields: MT Field Offset Type VT Attr Value Name 790fd8c4 40000b5 4 System.String 0 instance 042cbd04 _className 7910ebc8 40000b6 8 ...ection.MethodBase 0 instance 00000000 _exceptionMethod 790fd8c4 40000b7 c System.String 0 instance 00000000 _exceptionMethodString 790fd8c4 40000b8 10 System.String 0 instance 00000000 _message 79116114 40000b9 14 ...tions.IDictionary 0 instance 00000000 _data 790fdf04 40000ba 18 System.Exception 0 instance 042c73c8 _innerException 790fd8c4 40000bb 1c System.String 0 instance 00000000 _helpURL 790fd0f0 40000bc 20 System.Object 0 instance 00000000 _stackTrace 790fd8c4 40000bd 24 System.String 0 instance 00000000 _stackTraceString 790fd8c4 40000be 28 System.String 0 instance 00000000 _remoteStackTraceString 79102290 40000bf 34 System.Int32 1 instance 0 _remoteStackIndex 790fd0f0 40000c0 2c System.Object 0 instance 00000000 _dynamicMethods 79102290 40000c1 38 System.Int32 1 instance -2146233088 _HResult 790fd8c4 40000c2 30 System.String 0 instance 00000000 _source 791016bc 40000c3 3c System.IntPtr 1 instance 0 _xptrs 79102290 40000c4 40 System.Int32 1 instance -532459699 _xcode 7910be50 4002542 60 System.Boolean 1 instance 1 _isConnected 790fd8c4 4002543 44 System.String 0 instance 042ca6b4 _remoteAddr 790fd8c4 4002544 48 System.String 0 instance 042ca8cc _remotePort 790fd8c4 4002545 4c System.String 0 instance 042bd764 _userAgent 790fd8c4 4002546 50 System.String 0 instance 042c16ec _persistedState 790fd8c4 4002547 54 System.String 0 instance 042bd62c _referer 790fd8c4 4002548 58 System.String 0 instance 042bbe48 _path 790fd8c4 4002549 5c System.String 0 instance 042cb178 _message 7910be50 400254a 61 System.Boolean 1 instance 1 _macValidationError
The _message field is as follows:
0:033> !do 042cb178 Name: System.String MethodTable: 790fd8c4 EEClass: 790fd824 Size: 2104(0x838) bytes (C:\WINDOWS\assembly\GAC_32\mscorlib\2.0.0.0__b77a5c561934e089\mscorlib.dll) String: Invalid viewstate. Client IP: <ip_address> Port: 1449 User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727; .NET CLR 1.1.4322; .NET CLR 3.0.04506.30) ViewState: /wEPDwUJNDY5NzIzNzI1D2QWAgIDD2QWAgIBDxQrAAQPFg4eDkFzeW5jUmVuZGVyaW5nZx4UU2hvd1Byb21wdEFyZWFCdXR0b25nHgtab29tUGVyY2VudAJkHghab29t TW9kZQsphgFNaWNyb3NvZnQuUmVwb3J0aW5nLldlYkZvcm1zLlpvb21Nb2RlLCBSZXBvcnRpbmdTZXJ2aWNlc1dlYlNlcnZlciwgVmVyc2lvbj05LjAuMjQyLjAsIEN1bHR1cmU9bmV1 dHJhbCwgUHVibGljS2V5VG9rZW49ODk4NDVkY2Q4MDgwY2M5MQIeFERvY3VtZW50TWFwQ29sbGFwc2VkaB4OUmVuZGVyaW5nU3RhdGULKZIBTWljcm9zb2Z0LlJlcG9ydGluZy5XZWJGb 3Jtcy5SZXBvcnRSZW5kZXJpbmdTdGF0ZSwgUmVwb3J0aW5nU2VydmljZXNXZWJTZXJ2ZXIsIFZlcnNpb249OS4wLjI0Mi4wLCBDdWx0dXJlPW5ldXRyYWwsIFB1YmxpY0tleVRva2Vu PTg5ODQ1ZGNkODA4MGNjOTECHhBWMVN0eWxlU2hlZXROYW1lZGQoKVhTeXN0ZW0uR3VpZCwgbXNjb3JsaWIsIFZlcnNpb249Mi4wLjAuMCwgQ3VsdHVyZT1uZXV0cmFsLCBQdWJsaWNL ZXlUb2tlbj1iNzdhNWM1NjE5MzRlMDg5JGI2MzVjZjFkLTg4MGYtNDEyMC05Y2RjLTk2ZTE0ZGViYzRiMQIBFCsAARQrAAICARQrAAIFGGx3Y2d4MGIzZGI1MzB4NTVsY2F2eXA1NQIB FgpmDw8WAh4LSG... Fields: MT Field Offset Type VT Attr Value Name 79102290 4000096 4 System.Int32 1 instance 1044 m_arrayLength 79102290 4000097 8 System.Int32 1 instance 1043 m_stringLength 790ff328 4000098 c System.Char 1 instance 49 m_firstChar 790fd8c4 4000099 10 System.String 0 shared static Empty >> Domain:Value 000d49f0:790d884c 00101438:790d884c 1f7865b8:790d884c << 7912dd40 400009a 14 System.Char[] 0 shared static WhitespaceChars >> Domain:Value 000d49f0:0a2203f4 00101438:0a2244e8 1f7865b8:0226db3c <<
The ViewState in this error message is truncated, but we can get the entire string from _persistedState:
0:033> !do 042c16ec Name: System.String MethodTable: 790fd8c4 EEClass: 790fd824 Size: 10162(0x27b2) bytes (C:\WINDOWS\assembly\GAC_32\mscorlib\2.0.0.0__b77a5c561934e089\mscorlib.dll) String: /wEPDwUJNDY5NzIzNzI1D2QWAgIDD2QWAgIBDxQrAAQPFg4eDkFzeW5jUmVuZGVyaW5nZx4UU2hvd1Byb21wdEFyZWFCdXR0b25nHgtab29tUGVyY2VudAJkHghab29tTW9kZ QsphgFNaWNyb3NvZnQuUmVwb3J0aW5nLldlYkZvcm1zLlpvb21Nb2RlLCBSZXBvcnRpbmdTZXJ2aWNlc1dlYlNlcnZlciwgVmVyc2lvbj05LjAuMjQyLjAsIEN1bHR1cmU9bmV1dHJhbC wgUHVibGljS2V5VG9rZW49ODk4NDVkY2Q4MDgwY2M5MQIeFERvY3VtZW50TWFwQ29sbGFwc2VkaB4OUmVuZGVyaW5nU3RhdGULKZIBTWljcm9zb2Z0LlJlcG9ydGluZy5XZWJGb3Jtcy5 SZXBvcnRSZW5kZXJpbmdTdGF0ZSwgUmVwb3J0aW5nU2VydmljZXNXZWJTZXJ2ZXIsIFZlcnNpb249OS4wLjI0Mi4wLCBDdWx0dXJlPW5ldXRyYWwsIFB1YmxpY0tleVRva2VuPTg5ODQ 1ZGNkODA4MGNjOTECHhBWMVN0eWxlU2hlZXROYW1lZGQoKVhTeXN0ZW0uR3VpZCwgbXNjb3JsaWIsIFZlcnNpb249Mi4wLjAuMCwgQ3VsdHVyZT1uZXV0cmFsLCBQdWJsaWNLZXlUb2t lbj1iNzdhNWM1NjE5MzRlMDg5JGI2MzVjZjFkLTg4MGYtNDEyMC05Y2RjLTk2ZTE0ZGViYzRiMQIBFCsAARQrAAICARQrAAIFGGx3Y2d4MGIzZGI1MzB4NTVsY2F2eXA1NQIBFgpmDw8 WAh4LSGFzQ29udHJvbHNnZBYEZg8PFgIeDU9uQ2xpZW50Q2xpY2sF/wFyZXR1cm4gZG9jdW1lbnQuZ2V0RWxlbWVudEJ5SWQoJ1JlcG9ydFZpZXdlckNvbnRyb2xfY3RsMDAnKS5QYXJ hbWV0ZXJzQ29udHJvbGxlci5WYWxpZGF0ZUhhc1ZhbHVlKCdSZXBvcnRWaWV3ZXJDb250cm9sX2N0bDAwX2N0bDAzX3R4dFZhbHVlJywgJycsICdQbGVhc2UgZW50ZXIgYSB2YWx1ZSBm b3IgdGhlIHBhcmFtZXRlciBcJ86az4nOtM65zrrPjM+CIM6Rzq/PhM63z4POt8+CXCcuICBUaGUgcGFyYW1ldGVyIGNhbm5vdCBiZSBibGFuay4nKTtkZAIDD2QWAgIBDw8WAh4EVGV4d AUPNjQ4MTAxMTA4MDI0MTY1ZGQCAQ9kFg5mD2QWAmYPD2QWAh4Hb25jbGljawWoAWRvY3VtZW50LmdldEVsZW1lbnRCeUlkKCdSZXBvcnRWaWV3ZXJDb250cm9sJykuQ2xpZW50Q29udH JvbGxlci5TZXREb2NNYXBWaXNpYmlsaXR5KCFkb2N1bWVudC5nZXRFbGVtZW50QnlJZCgnUmVwb3J0Vmlld2VyQ29udHJvbCcpLkNsaWVudENvbnRyb2xsZXIuSXNEb2NNYXBWaXNpYmx lKCkpOxYCZg8PFgYeBVdpZHRoGwAAAAAAADBAAQAAAB4GSGVpZ2h0GwAAAAAAADBAAQAAAB4EXyFTQgKAAxYCHgVzdHlsZQUMcGFkZGluZzoycHg7ZAIBD2QWCmYPZBYCAgEPZBYCZg8P FgYfCxsAAAAAAAAwQAEAAAAfDBsAAAAAAAAwQAEAAAAfDQKAAxYCHw4FDHBhZGRpbmc6MnB4O2QCAQ9kFgICAQ9kFgJmDw8WBh8LGwAAAAAAADBAAQAAAB8MGwAAAAAAADBAAQAAAB8NA oADFgIfDgUMcGFkZGluZzoycHg7ZAICDw8WBB8JZR4HRW5hYmxlZGgWAh4Kb25rZXlwcmVzcwWNA2lmIChldmVudC5rZXlDb2RlID09IDEwIHx8IGV2ZW50LmtleUNvZGUgPT0gMTMpI HsNCnZhciBwYWdlTnVtYmVyID0gcGFyc2VJbnQodGhpcy52YWx1ZSwgMTApOw0KaWYgKGlzTmFOKHBhZ2VOdW1iZXIpIHx8IHBhZ2VOdW1iZXIgPCAxIHx8IHBhZ2VOdW1iZXIgPiBkb 2N1bWVudC5nZXRFbGVtZW50QnlJZCgnUmVwb3J0Vmlld2VyQ29udHJvbCcpLkNsaWVudENvbnRyb2xsZXIuVG90YWxQYWdlcykNCiAgICBhbGVydCgnRW50ZXIgYSB2YWxpZCBwYWdlI G51bWJlcicpOw0KZWxzZQ0KICAgIGRvY3VtZW50LmdldEVsZW1lbnRCeUlkKCdSZXBvcnRWaWV3ZXJDb250cm9sJykuQ2xpZW50Q29udHJvbGxlci5BY3Rpb25IYW5kbGVyKCdQYWdlT mF2JywgcGFnZU51bWJlcik7OzsgcmV0dXJuIGZhbHNlO31kAgUPZBYCAgEPZBYCZg8PFgYfCxsAAAAAAAAwQAEAAAAfDBsAAAAAAAAwQAEAAAAfDQKAAxYCHw4FDHBhZGRpbmc6MnB4O 2QCBg9kFgICAQ9kFgJmDw8WBh8LGwAAAAAAADBAAQAAAB8MGwAAAAAAADBAAQAAAB8NAoADFgIfDgUMcGFkZGluZzoycHg7ZAICD2QWAmYPZBYCAgEPZBYCZg8PFgYfCxsAAAAAAAAwQ AEAAAAfDBsAAAAAAAAwQAEAAAAfDQKAAxYCHw4FDHBhZGRpbmc6MnB4O2QCAw9kFgJmDxAPZBYEHghvbmNoYW5nZQVgZG9jdW1lbnQuZ2V0RWxlbWVudEJ5SWQoJ1JlcG9ydFZpZXdlc kNvbnRyb2wnKS5DbGllbnRDb250cm9sbGVyLlNldFpvb20oZXZlbnQuc3JjRWxlbWVudC52YWx1ZSk7HghkaXNhYmxlZAUIZGlzYWJsZWRkFgECBWQCBA9kFgJmDw8WAh8PaBYEHhBvb nByb3BlcnR5Y2hhbmdlBaMCaWYgKGV2ZW50LnByb3BlcnR5TmFtZSA9PSAndmFsdWUnKQ0Kew0KICAgIGRvY3VtZW50LmdldEVsZW1lbnRCeUlkKCdSZXBvcnRWaWV3ZXJDb250cm9sX 2N0bDAxX2N0bDA0X2N0bDAxJykuQ29udHJvbGxlci5TZXRWaWV3ZXJMaW5rQWN0aXZlKHRoaXMudmFsdWUgIT0gbnVsbCAmJiB0aGlzLnZhbHVlICE9ICcnKTsNCiAgICBkb2N1bWVud C5nZXRFbGVtZW50QnlJZCgnUmVwb3J0Vmlld2VyQ29udHJvbF9jdGwwMV9jdGwwNF9jdGwwMycpLkNvbnRyb2xsZXIuU2V0Vmlld2VyTGlua0FjdGl2ZShmYWxzZSk7DQp9HxAF4QFpZ iAoZXZlbnQua2V5Q29kZSA9PSAxMCB8fCBldmVudC5rZXlDb2RlID09IDEzKSB7ZG9jdW1lbnQuZ2V0RWxlbWVudEJ5SWQoJ1JlcG9ydFZpZXdlckNvbnRyb2wnKS5DbGllbnRDb250c m9sbGVyLkFjdGlvbkhhbmRsZXIoJ1NlYXJjaCcsIGRvY3VtZW50LmdldEVsZW1lbnRCeUlkKCdSZXBvcnRWaWV3ZXJDb250cm9sX2N0bDAxX2N0bDA0X2N0bDAwJykudmFsdWUpOzsgc mV0dXJuIGZhbHNlO31kAgcPZBYCZg9kFgICAQ9kFgJmDw8WBh8LGwAAAAAAADBAAQAAAB8MGwAAAAAAADBAAQAAAB8NAoADFgIfDgUMcGFkZGluZzoycHg7ZAIID2QWAmYPZBYCAgEPZ BYCZg8PFgYfCxsAAAAAAAAwQAEAAAAfDBsAAAAAAAAwQAEAAAAfDQKAAxYCHw4FDHBhZGRpbmc6MnB4O2QCBg8WAh4FVmFsdWUFATFkAgcPFgIfFAUFZmFsc2VkAggPFgIfFAUFZmFsc 2VkGAEFHl9fQ29udHJvbHNSZXF1aXJlUG9zdEJhY2tLZXlfXxYQBStSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDAwJGN0bDAwJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJ GN0bDAxJGN0bDAxJGN0bDAwJGN0bDAwJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDAxJGN0bDAwJGN0bDAxJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0b DAxJGN0bDAxJGN0bDAxJGN0bDAwJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDAxJGN0bDAxJGN0bDAxJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJ GN0bDAxJGN0bDA1JGN0bDAwJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDAxJGN0bDA1JGN0bDAxJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0b DAxJGN0bDA2JGN0bDAwJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDAxJGN0bDA2JGN0bDAxJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDAyJ GN0bDAwJGN0bDAwJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDAyJGN0bDAwJGN0bDAxJGN0bDAwBStSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDA2JGN0b DAwJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDA3JGN0bDAwJGN0bDAwJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDA3JGN0bDAwJGN0bDAxJ GN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDA4JGN0bDAwJGN0bDAwJGN0bDAwBTFSZXBvcnRWaWV3ZXJDb250cm9sJGN0bDAxJGN0bDA4JGN0bDAwJGN0bDAxJGN0b DAwX2RaxoBglgh8qbVp7F4IKaK6C+A= Fields: MT Field Offset Type VT Attr Value Name 79102290 4000096 4 System.Int32 1 instance 5073 m_arrayLength 79102290 4000097 8 System.Int32 1 instance 5072 m_stringLength 790ff328 4000098 c System.Char 1 instance 2f m_firstChar 790fd8c4 4000099 10 System.String 0 shared static Empty >> Domain:Value 000d49f0:790d884c 00101438:790d884c 1f7865b8:790d884c << 7912dd40 400009a 14 System.Char[] 0 shared static WhitespaceChars >> Domain:Value 000d49f0:0a2203f4 00101438:0a2244e8 1f7865b8:0226db3c <<
There is also an _innerException we can look at:
0:033> !do 042c73c8 Name: System.Web.HttpException MethodTable: 663dc0d4 EEClass: 663dc05c Size: 84(0x54) bytes (C:\WINDOWS\assembly\GAC_32\System.Web\2.0.0.0__b03f5f7f11d50a3a\System.Web.dll) Fields: MT Field Offset Type VT Attr Value Name 790fd8c4 40000b5 4 System.String 0 instance 042cbd58 _className 7910ebc8 40000b6 8 ...ection.MethodBase 0 instance 00000000 _exceptionMethod 790fd8c4 40000b7 c System.String 0 instance 00000000 _exceptionMethodString 790fd8c4 40000b8 10 System.String 0 instance 042c745c _message 79116114 40000b9 14 ...tions.IDictionary 0 instance 00000000 _data 790fdf04 40000ba 18 System.Exception 0 instance 00000000 _innerException 790fd8c4 40000bb 1c System.String 0 instance 00000000 _helpURL 790fd0f0 40000bc 20 System.Object 0 instance 042c74a0 _stackTrace 790fd8c4 40000bd 24 System.String 0 instance 00000000 _stackTraceString 790fd8c4 40000be 28 System.String 0 instance 00000000 _remoteStackTraceString 79102290 40000bf 34 System.Int32 1 instance 0 _remoteStackIndex 790fd0f0 40000c0 2c System.Object 0 instance 00000000 _dynamicMethods 79102290 40000c1 38 System.Int32 1 instance -2147467259 _HResult 790fd8c4 40000c2 30 System.String 0 instance 00000000 _source 791016bc 40000c3 3c System.IntPtr 1 instance 0 _xptrs 79102290 40000c4 40 System.Int32 1 instance -532459699 _xcode 79102290 4001029 48 System.Int32 1 instance 0 _httpCode 663e49c4 400102a 44 ...eb.ErrorFormatter 0 instance 00000000 _errorFormatter 79102290 400102b 4c System.Int32 1 instance 0 _webEventCode 0:033> !do 042c745c Name: System.String MethodTable: 790fd8c4 EEClass: 790fd824 Size: 66(0x42) bytes (C:\WINDOWS\assembly\GAC_32\mscorlib\2.0.0.0__b77a5c561934e089\mscorlib.dll) String: Unable to validate data. Fields: MT Field Offset Type VT Attr Value Name 79102290 4000096 4 System.Int32 1 instance 25 m_arrayLength 79102290 4000097 8 System.Int32 1 instance 24 m_stringLength 790ff328 4000098 c System.Char 1 instance 55 m_firstChar 790fd8c4 4000099 10 System.String 0 shared static Empty >> Domain:Value 000d49f0:790d884c 00101438:790d884c 1f7865b8:790d884c << 7912dd40 400009a 14 System.Char[] 0 shared static WhitespaceChars >> Domain:Value 000d49f0:0a2203f4 00101438:0a2244e8 1f7865b8:0226db3c <<
So we know in this case we are unable to validate the ViewState; we can also paste the ViewState string from _persistedState in ViewState Decoder
The “Character Count” value is just a bit more than 5.000, not much for the complex pages we were looking at… Depending on their configuration, firewall and/or proxies software can truncate fields and values exceeding a certain amount of bytes, and this is another known cause for InvalidViewstateExceptions. Who can we quickly check?
A network trace can help, but as an empiric test we can use LogParser on IIS logs. These are the maximum, average and minimum amount of bytes send from the server as a result of a GET to an aspx page:
logparser
"select max(sc-bytes), avg(sc-bytes), min(sc-bytes) from *.log
where to_lowercase(extract_extension(cs-uri-stem))='aspx' and to_lowercase(cs-method)='get'" -i:iisw3c
MAX(ALL sc-bytes) AVG(ALL sc-bytes) MIN(ALL sc-bytes)
----------------- ----------------- -----------------
72756 44009 448
And these are the same values, calculated on the bytes posted from the clients:
logparser
"select max(cs-bytes), avg(cs-bytes), min(cs-bytes) from *.log
where to_lowercase(extract_extension(cs-uri-stem))='aspx' and to_lowercase(cs-method)='post'" -i:iisw3c
MAX(ALL cs-bytes) AVG(ALL cs-bytes) MIN(ALL cs-bytes)
----------------- ----------------- -----------------
11662 4620 819
Uhm… the server is sending an average of about 44 Kb and the clients are posting an average of less than 5 Kb… also the maximum values are quite different. Not a crushing proof but still something to keep in mind…
A quick check on customer’s network revealed they actually had configured (I think for security reasons) a maximum allowed size for HTML incoming fields and due to some policies and constraints they had, we could not increase that value. Ok, now what?
Enter MaxPageStateFieldLength
Luckily, we can configure the MaxPageStateFieldLength property exactly for this purpose:
When the MaxPageStateFieldLength property is set to a positive number, the view state sent to the client browser is broken into multiple hidden fields, and each field’s value is less than the size specified in the MaxPageStateFieldLength property.
Setting the MaxPageStateFieldLength property to a negative number (the default) indicates that the view-state field should not be separated into chunks. Setting the MaxPageStateFieldLength to a small number may result in poor performance.
Set the value of the MaxPageStateFieldLength property in the pages element of the Web.config file.
We set the values to something less than 5 Kb and the problem magically disappeared ?
Carlo
Quote of the day:
Have a heart that never hardens, and a temper that never tires, and a touch that never hurts — Charles Dickens