System.nullreferenceexception: creating pdf with itextsharp

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hello guys,
i get error creting pdf with itextsharp, this is my code

Dim Documento As New Document(PageSize.A4, 100, 100, 25, 25)
       Dim fileStream As New FileStream("D:\test.pdf", FileMode.Create, FileAccess.Write, FileShare.None)
       Dim Scrittura As PdfWriter = PdfWriter.GetInstance(Documento, fileStream)

at the third line i get error: System.NullReferenceException: 'Object reference not set to an instance of an object.' I work with Viusal studio 2019, in Visual 2010 the code works fine.
Please help me

What I have tried:

different version of Itext lib (5.5, 7.1)

Posted 1-Mar-24 9:21am

Fabrizio Menichelli

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Richard MacCutchan 2-Mar-24 4:44am

The message suggests that either Documento or fileStream initialisations failed, and are therefor null. An easy thing to check with the debugger.

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Dave Kreskowiak · Answer 1 · 2024-03-01T13:02:00

This is an error where nobody can diagnose it for you, but you have the power to do it yourself.

Run the code under the debugger. When the error occurs, the debugger will show you the exception and the line that is throwing it. How the mouse on the PdfWriter name, then the Documento and fileStream names. If any of them show null, there's your problem. YOU then have to work backwards in the code you find out why that name is null. Nobody can do that for you.

OriginalGriff · Answer 2 · 2024-03-01T19:00:00

To add to what Dave has said ...

This is one of the most common problems we get asked, and it's also the one we are least equipped to answer, but you are most equipped to answer yourself.

Let me just explain what the error means: You have tried to use a variable, property, or a method return value but it contains null - which means that there is no instance of a class in the variable.
It's a bit like a pocket: you have a pocket in your shirt, which you use to hold a pen. If you reach into the pocket and find there isn't a pen there, you can't sign your name on a piece of paper - and you will get very funny looks if you try! The empty pocket is giving you a null value (no pen here!) so you can't do anything that you would normally do once you retrieved your pen. Why is it empty? That's the question - it may be that you forgot to pick up your pen when you left the house this morning, or possibly you left the pen in the pocket of yesterday's shirt when you took it off last night.

We can't tell, because we weren't there, and even more importantly, we can't even see your shirt, much less what is in the pocket!

Back to computers, and you have done the same thing, somehow - and we can't see your code, much less run it and find out what contains null when it shouldn't.
But you can - and Visual Studio will help you here. Run your program in the debugger and when it fails, it will show you the line it found the problem on. You can then start looking at the various parts of it to see what value is null and start looking back through your code to find out why. So put a breakpoint at the beginning of the method containing the error line, and run your program from the start again. This time, the debugger will stop before the error, and let you examine what is going on by stepping through the code looking at your values.

But we can't do that - we don't have your code, we don't know how to use it if we did have it, we don't have your data. So try it - and see how much information you can find out!

Fabrizio Menichelli · Answer 3 · 2024-03-02T21:32:00

Solution 3

Solution is to put flag in Exception Setting "Break when this exception type is thrown except when thrown from itextsharp.dll".
maybe it was a known problem....
regards

Posted 2-Mar-24 21:32pm

Fabrizio Menichelli

System.nullreferenceexception: creating pdf with itextsharp

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