System.NullReferenceException occurred in Unknown Module - C# Discussion Boards

Searching DataSets with multiple strings

22-Mar-05 9:25

And this means what to us?

Joshua Lunsford22-Mar-05 3:27

Joshua Lunsford

22-Mar-05 3:27

This is what i'm trying and it is not working... any clues?

<br />
SqlDataAdapter adp = new SqlDataAdapter(myCommand);<br />
DataSet ds = new DataSet();<br />
adp.Fill(ds);<br />
ds.Tables[0].Select("COLUMN1 LIKE '*" + string1 + "*', COLUMN2 LIKE '*" + string2 + "*', COLUMN3 LIKE '*" + string3 + "*'");<br />
MyRepeater.DataSource=ds.Tables[0].DefaultView;<br />
MyRepeater.DataBind();<br />

System.NullReferenceException occurred in Unknown Module

AO-Action22-Mar-05 1:36

AO-Action

22-Mar-05 1:36

Hi every body... I'v searched the comments, I did find pieces of information here and there but it's not even near the bull's-eye, so I decided to post a new thread hopping for someone to help me getting out of this problem Smile | :)

the main/parent form is an MDI form and the child is a normal form. The problem accurres after the user selects the child from parent's mainmenu, during the process of loding the child form I get this message
http://mars.walagata.com/w/action/DotNet/unhand.jpg[^]
"An unhandled exception of type 'System.NullReferenceException' occurred in Unknown Module. Additional information: Object reference is not set to an instance of an object."

and after I clicked the continue, the child form runs without any prob. butif I clicked the Break this messagebox shows up
http://mars.walagata.com/w/action/DotNet/there-is.jpg[^]

this is part of the code related to the problem (I think)
the parent part... calling the child

AccountEdit editAccount = new AccountEdit();<br />
editAccount.MdiParent = this;<br />
editAccount.Show();

I removed the "MdiParent = ..." and its the same, changed the Show() to ShowDialog() and still the same

the chiled part..
I DIDN'T CODE ANY THING, I just draged and droped controls and rearrange them on the form. The one thing I remember is that this problem started to showup after I add any list control and this time I added ListView control.
Here is a link to the code (I don't want to make this message long) :
http://mars.walagata.com/w/action/DotNet/code.txt[^]

after reading some posts that said that this only accurres in the VS.net 2003 environment, I decided to ignore this exception http://mars.walagata.com/w/action/DotNet/exception.jpg[^]
some other posts said that uninstalling and reinstalling the framework will solve the prob but I don't believe so

It is related to referencing null value only after the Show(), so any ideas?

and another question, why after some time I can't type '{' in vs.net?

Re: System.NullReferenceException occurred in Unknown Module

Robert Rohde22-Mar-05 2:05

Robert Rohde

22-Mar-05 2:05

Sounds really strange...

I would do the following: Surround your ShowDialog call with a try catch block and look at the stack of the exception (and post it here). This will hopefully give further hints.

<br />
try {<br />
editAccount.Show();<br />
} catch (Exception exc) {<br />
Console.WriteLine(exc.StackTrace);<br />
}<br />

Re: System.NullReferenceException occurred in Unknown Module

AO-Action22-Mar-05 2:31

AO-Action

22-Mar-05 2:31

Thanks alot Rohde for your reply,
I did and the same message still comming

hopefully that the framework 1.1 SP1 will solve this problem, Microsoft mentioned some NullReferenceException errors were fixed in this SP, I hope I didn't install this fix before but anyway assume that the problem remains even after I installed the SP, any ideas?

and if this fix did the job I'll report back Smile | :)

How to get text on screen

levgiang22-Mar-05 0:39

levgiang

22-Mar-05 0:39

How can i write a program can get text at current mouse position

le van giang

Re: How to get text on screen

leppie22-Mar-05 1:07

leppie

22-Mar-05 1:07

With great difficulty. The only way to do it generically is to do OCR.

^{xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots}

Re: How to get text on screen

Dave Kreskowiak22-Mar-05 4:48

22-Mar-05 4:48

And I think I've told you this before...

And leppie's comment "with great difficulty" is an understatement!

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

list view goes blank

maheshfour21-Mar-05 23:12

maheshfour

21-Mar-05 23:12

hi all,

I am facing with an unusual problem. i am doing a project involving TCP/IP packet capturing. I display the packets in a list view. it works most of the times except the first time.

For the first time when i click start button the list view goes blank. after that it works properly.

can any one help me?

Re: list view goes blank

Dave Kreskowiak22-Mar-05 4:45

22-Mar-05 4:45

That depends entirely on how your filling the ListView while your capturing packets. Are you letting the ListView update itself after filling it with data? Is your packet capture process running on the same thread of the UI? If so, then you're going to have to call Application.DoEvents to let the Window and it's controls redraw themselves. A better method would be to run the capture process on a seperate thread and have it post calls back to the Window with the ListView telling it to add the data, possibly using an event.

Also, consider that you can't possibly update the ListView fast enough to post every packet that flies by as it does so. You might want to hold off updating the ListView until the capture is finished, then you can populate the ListView however you want.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

tabs in tree view

Anonymous21-Mar-05 23:05

21-Mar-05 23:05

hi friends,

how can i indent the data ( nodes ) in a tree view using tab. I tried using "\t" in the node string, but it displays a square character in the node instead of indenting.

mahesh

Re: tabs in tree view

Dave Kreskowiak22-Mar-05 4:39

22-Mar-05 4:39

The TreeView doesn't support the Tab character. You'll either have to TRY prepending the strings with Space characters or do without. Since it's a TreeView that already does indenting for child nodes, I really have a hard time thinking of a good reason to use such formatting...

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

file system protection

computer_eng21-Mar-05 22:52

computer_eng

21-Mar-05 22:52

Hi ineed help about hoe i can write code in c# that protect my file and folder from delete and write and if i want protect file from open.... thanks for any one help me

James Poulose21-Mar-05 23:37

James Poulose

21-Mar-05 23:37

WHy don't you try the FileSystemWatcher namespace ?

James

Anonymous22-Mar-05 22:01

22-Mar-05 22:01

thank you for response but i try but this name space
give you tha ability to rebort about chang after it happend

Dave Kreskowiak22-Mar-05 4:37

22-Mar-05 4:37

You'll have to write a file system extension to accomplish this. This is NOT a project for the faint of heart or weak in COM Interop and NTFS extension skills.

Here's a better idea. Just use the normal NTFS Security permissions. The requirements you specified are exactly what Security is for.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Anonymous22-Mar-05 22:47

22-Mar-05 22:47

thank you for your response and thank you for your advice
but how i can write code in c# that help me to do the security using ntfs;)

Dave Kreskowiak23-Mar-05 0:43