Exception: "Value cannot be null. Parameter name:s"

  • Thread starter Thread starter Chris Herring
  • Start date Start date
C

Chris Herring

Hi there: Well, let me start off by saying that I am a Visual Studio drag
and drop weenie, not a real programmer. So I tend to get confused when
things do not look like the instructions said they were going to look :) .
Here is my current dilemma:

I am having a strange problem with my ASP.NET application. I am building the
application using Visual Basic .Net in Visual Studio.NET 2003. Lately, I
have frequently been getting the following exception (see below) when I
debug the application. If I step through my code and determine what is
actually broken (the exception is not very informative), I find that the
error has nothing whatsoever to do with the exception that is thrown. The
really, really strange thing is this: When I get this error, the "real"
exception always seems to be thrown from my code contained in a .vb class
file. If I create a new .vb file, and cut-and-paste the code into the new
file, delete the old file, and then re-run the application (with no actual
changes to the code whatsoever), then I get the "real" exception instead of
the "value cannot be null" exception. I have dozens and dozens of .vb class
files.. so far have gone through this process on about 10 files. This is
getting annoying. Has anyone experienced anything like this? I searched
newsgroups and ms knowledgebase, but I did not find anything resembling my
problem.
-----------------------
The exception:

Value cannot be null. Parameter name: s
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.ArgumentNullException: Value cannot be null.
Parameter name: s

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:

[ArgumentNullException: Value cannot be null.
Parameter name: s]
System.IO.StringReader..ctor(String s) +78
System.Web.FormatterWithFileInfo.GetSourceFileLines(String fileName,
Encoding encoding, String sourceCode, Int32 lineNumber)
System.Web.UnhandledErrorFormatter.get_ColoredSquareContent()
System.Web.ErrorFormatter.GetHtmlErrorMessage(Boolean
dontShowSensitiveInfo)
System.Web.HttpResponse.WriteErrorMessage(Exception e, Boolean
dontShowSensitiveErrors)
System.Web.HttpResponse.ReportRuntimeError(Exception e, Boolean canThrow)
System.Web.HttpRuntime.FinishRequest(HttpWorkerRequest wr, HttpContext
context, Exception e)
 
Dear Weenie,
without getting too deep into it....
your stack dump shows:
System.IO.StringReader..ctor(String s) +78
where s is (presumably) the parameter it is complaining about beging null.
A quick look in the docs shows the the consrtuctor (ctor) wants to have a
non-null string
since StringReader sits below things like TextReader. Are you passing a
null string when you should be providing a file name??????????

hope this helps.

dlr



Chris Herring said:
Hi there: Well, let me start off by saying that I am a Visual Studio drag
and drop weenie, not a real programmer. So I tend to get confused when
things do not look like the instructions said they were going to look :) .
Here is my current dilemma:

I am having a strange problem with my ASP.NET application. I am building the
application using Visual Basic .Net in Visual Studio.NET 2003. Lately, I
have frequently been getting the following exception (see below) when I
debug the application. If I step through my code and determine what is
actually broken (the exception is not very informative), I find that the
error has nothing whatsoever to do with the exception that is thrown. The
really, really strange thing is this: When I get this error, the "real"
exception always seems to be thrown from my code contained in a .vb class
file. If I create a new .vb file, and cut-and-paste the code into the new
file, delete the old file, and then re-run the application (with no actual
changes to the code whatsoever), then I get the "real" exception instead of
the "value cannot be null" exception. I have dozens and dozens of .vb class
files.. so far have gone through this process on about 10 files. This is
getting annoying. Has anyone experienced anything like this? I searched
newsgroups and ms knowledgebase, but I did not find anything resembling my
problem.
-----------------------
The exception:

Value cannot be null. Parameter name: s
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.ArgumentNullException: Value cannot be null.
Parameter name: s

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:

[ArgumentNullException: Value cannot be null.
Parameter name: s]
System.IO.StringReader..ctor(String s) +78
System.Web.FormatterWithFileInfo.GetSourceFileLines(String fileName,
Encoding encoding, String sourceCode, Int32 lineNumber)
System.Web.UnhandledErrorFormatter.get_ColoredSquareContent()
System.Web.ErrorFormatter.GetHtmlErrorMessage(Boolean
dontShowSensitiveInfo)
System.Web.HttpResponse.WriteErrorMessage(Exception e, Boolean
dontShowSensitiveErrors)
System.Web.HttpResponse.ReportRuntimeError(Exception e, Boolean canThrow)
System.Web.HttpRuntime.FinishRequest(HttpWorkerRequest wr, HttpContext
context, Exception e)

----------------------

Regards,

Chris Herring
Click to expand...
 
Dennis:

Thanks for your reply.

I think I have figured out what was happening. The second line in the stack
trace:

System.Web.FormatterWithFileInfo.GetSourceFileLines

made me wonder if perhaps the debugger could not access the source file to
display the stack trace for the "real" exception. Sure enough.. when I
checked the priveleges on the source files the ASP.NET process did not have
access to the files. I gave asp.net read access to the source files and the
problem went away.

Best regards,

Weenie

Dennis Redfield said:
Dear Weenie,
without getting too deep into it....
your stack dump shows:
System.IO.StringReader..ctor(String s) +78
where s is (presumably) the parameter it is complaining about beging null.
A quick look in the docs shows the the consrtuctor (ctor) wants to have a
non-null string
since StringReader sits below things like TextReader. Are you passing a
null string when you should be providing a file name??????????

hope this helps.

dlr



Chris Herring said:
Hi there: Well, let me start off by saying that I am a Visual Studio drag
and drop weenie, not a real programmer. So I tend to get confused when
things do not look like the instructions said they were going to look :) ..
Here is my current dilemma:

I am having a strange problem with my ASP.NET application. I am building the
application using Visual Basic .Net in Visual Studio.NET 2003. Lately, I
have frequently been getting the following exception (see below) when I
debug the application. If I step through my code and determine what is
actually broken (the exception is not very informative), I find that the
error has nothing whatsoever to do with the exception that is thrown. The
really, really strange thing is this: When I get this error, the "real"
exception always seems to be thrown from my code contained in a .vb class
file. If I create a new .vb file, and cut-and-paste the code into the new
file, delete the old file, and then re-run the application (with no actual
changes to the code whatsoever), then I get the "real" exception instead of
the "value cannot be null" exception. I have dozens and dozens of .vb class
files.. so far have gone through this process on about 10 files. This is
getting annoying. Has anyone experienced anything like this? I searched
newsgroups and ms knowledgebase, but I did not find anything resembling my
problem.
-----------------------
The exception:

Value cannot be null. Parameter name: s
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.ArgumentNullException: Value cannot be null.
Parameter name: s

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:

[ArgumentNullException: Value cannot be null.
Parameter name: s]
System.IO.StringReader..ctor(String s) +78
System.Web.FormatterWithFileInfo.GetSourceFileLines(String fileName,
Encoding encoding, String sourceCode, Int32 lineNumber)
System.Web.UnhandledErrorFormatter.get_ColoredSquareContent()
System.Web.ErrorFormatter.GetHtmlErrorMessage(Boolean
dontShowSensitiveInfo)
System.Web.HttpResponse.WriteErrorMessage(Exception e, Boolean
dontShowSensitiveErrors)
System.Web.HttpResponse.ReportRuntimeError(Exception e, Boolean canThrow)
System.Web.HttpRuntime.FinishRequest(HttpWorkerRequest wr, HttpContext
context, Exception e)

----------------------

Regards,

Chris Herring
Click to expand...
Click to expand...
 
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