CSharp Studying - C# Discussion Boards

Re: Strange exception in a strange thread

4-Jan-04 8:16

Many threads are created that handle various things, like painting a control or for asynchronous operations. You never know.

Make sure you're compiling a debug build. There's other reasons you might not be able to use some of the debugging tools (threads are always funny when it comes to that), but just to eliminate the obvious I mentioned that.

If you think it has something to do with threading, check that your application's Main entry point is attributed with the STAThreadAttribute, which is the main UI thread. Usually, though, you get different errors if your application is started in anything other than an STA.

As far as changes 1.0 to 1.1, there really isn't much besides new methods and a few new classes, and a few methods and properties that are now obsolete - nothing conceptual is mentioned, though.

All I can think is to click on the Debug->Exceptions menu and break on all exceptions. Changes are that you'll end up looking at assembler code, but it should give you some stack frame if the debugging symbols are loaded. If you're not using a checked build of Windows, they are probably stripped. VC++ does install some program database (pdb files), but not for the core libraries. If you dig around though, you should at least be able to determine which library you're in. That could help solve the problem since most libraries are pretty specialized.

-----BEGIN GEEK CODE BLOCK-----
Version: 3.21
GCS/G/MU d- s: a- C++++ UL@ P++(+++) L+(--) E--- W+++ N++ o+ K? w++++ O- M(+) V? PS-- PE Y++ PGP++ t++@ 5 X+++ R+@ tv+ b(-)>b++ DI++++ D+ G e++>+++ h---* r+++ y+++
-----END GEEK CODE BLOCK-----

Broken God4-Jan-04 9:58

Broken God

4-Jan-04 9:58

OK, thanks for the help. I'll try and see what happens with all exceptions breaking into the debugger on throw.

CSharp Studying

Melanius4-Jan-04 0:04

Melanius

4-Jan-04 0:04

(Not sure if i had to post this here, couldn't find a forums here more fitting, if it's supposed to go elsewhere please remove).

I just finished readying: "Teach yourself C# in 24 Hours, by James Foxall", it really was a nice book, but i feel there are parts it discussed that didn't "fill" my knowledge as much as i'd like. Could someone propose a book, a set of books, or a complete training course that it is best for, learning CSharp, understaning OOP as a concept, and taking you to the next level, an intermediate status to pro (well pro without a proffesional experience).

Thanks in advance

leppie4-Jan-04 1:01

leppie

4-Jan-04 1:01

The next thing is to read all the .NET frameworks docs in MSDN from start to finish. That should keep you busy for a year or 2, but you will be a "pro" Smile | :)

To reach the next level, you will have to study the EMCA-334/5 C#/.NET CLR specs to answer all your questions you have left Smile | :)

After that stage, you can rename yourself to Heath Stewart or something :p

leppie ::AllocCPArticle("Zee blog");
Seen on my Campus BBS: Linux is free...coz no-one wants to pay for it.

Melanius4-Jan-04 2:40

Melanius

4-Jan-04 2:40

Thanks ofr pointing these things out for me, but the problem is, i don't trust myself yet to start searching on my own, performing quantum leaps. Even with having finished that book and all the examples/tests in it, i cannot write a simple program on my own, without having 100 backdraws and stuff. Meaning i cannot make code decisions yet, i just type like a blind and hope that this will work. That's why i asked for a book/s that will help me answer questions ( that maybe now i don't know i have, but will surely stumble upon later), and will serve as a quide to get me on knowledge-train, then i will surely have to dig on MSDN library (and CSharp Dev center). And i am also lacking OOP knowledge (only thing i know is what i've read in this book) 'cause C# is the first "real" language i started studying, no c++ background etc.

So if there's a book/s that would fit my needs as i mentioned above, please help me make the right choice Smile | :)

p.s. What is ECMA-334/5 C#/.NET CLR (common language runtime)?

Nick Parker4-Jan-04 6:18

Nick Parker

4-Jan-04 6:18

leppie wrote:
After that stage, you can rename yourself to Heath Stewart or something :p

Good call. Laugh | :laugh:

- Nick Parker
My Blog

Michael P Butler4-Jan-04 3:53

Michael P Butler

4-Jan-04 3:53

If it's C# you are interested in, then I'd recommend Inside C# by Tom Archer. I certainly think it is the definitive tome on C# the language.

IMO, The only true way to learn is by doing. Books like Teach yourself x in 24 hours are okay for beginners. The best way to learn is to write your own code and read code done by others. There are plenty of good C# examples here at CP to download and read. The only way to learn is to make the mistakes and ask questions when you get stuck.

Michael

Look at what's happened to me-,
I can't believe it myself.
Suddenly I'm up on top of the world,
It should've been somebody else. - The Greatest American Hero (1981)

Loading assemblies

peon20043-Jan-04 21:56

peon2004

3-Jan-04 21:56

Sorry for this question but I'm looking for a quick answer.

How does .NET load assemblies? - or better how does .NET find the assemblies to load?
For example: if I have myexe.exe which uses mydll.dll myseconddll.dll, etc. does the runtime scan the folder containing myexe.exe for all .dlls and loads them? What if I have 1000 .dlls in a single folder? Will the runtime load them all or just will scan them all?

My exact question is: I want to organize my program like that
main.exe
system/system.dll
system/gui.dll
plugins/someplugin.dll
plugins/moreplugins.dll
As you might guess what is in ./system/ will always be available and used by main.exe but what is in ./plugins/ could be different.

What methods do we have available to load .dlls? I'm currently reading Sam Haidar's article on late binding. Are there any other methods?

Could you please point me to information, where I can find an answer about this question.

I hope my question is clear enough.

Re: Loading assemblies

leppie3-Jan-04 22:13

leppie

3-Jan-04 22:13

.NET will first look if an Assembly with the same version number is in the GAC, then it falls back to the ~~working~~ executable's directory Smile | :)

leppie ::AllocCPArticle("Zee blog");
Seen on my Campus BBS: Linux is free...coz no-one wants to pay for it.

Re: Loading assemblies

Heath Stewart4-Jan-04 8:09

inserting images into access database

4-Jan-04 8:09

It also looks in the private path, which can be configured in the application's .config file using the <probing> element (see SDK documentation for details).

Re: Loading assemblies

Broken God4-Jan-04 0:27

Broken God

4-Jan-04 0:27

Well, I did plugin loading by first just listing all the DLL files in the plugins directory and then calling Assembly.Load() (I think that's what it was called) for each of them and specifying the file as the parameter.

Steve1_rm3-Jan-04 16:19

Steve1_rm

3-Jan-04 16:19

Hello

I am creating a database which will be used to display information and pictures for houses. I have done everything but be able to insert the pictures and retrieve them from the database.

This is the code l am using to make the connection with the database

//Example Connection
m_cnADONetConnection.ConnectionString = @"Provider=Microsoft.jet.OLEDB.4.0;data source=C:\Houses";
m_daDataAdapter = new OleDbDataAdapter("Select * From Houses",m_cnADONetConnection);
OleDbCommandBuilder m_cbCommandBuilder = new OleDbCommandBuilder(m_daAdapter);
m_daDataAdapeter.Fill(m_dtContacts);

//This is what i am using to retrieve from the database, not sure how to do this for a image control.
txtHouseID.text = Rows[rowPosition]["HouseID"].ToString();

To select the picture l want to add to the database, l am using a open dialog box, which works, but l can't add it to the database.

Many thanks in advance

Steve

Heath Stewart3-Jan-04 17:30

3-Jan-04 17:30

First, learn to use OleDbParameter. This will greatly aide in your problems. Second, set the column in which you want to store the image to an OLEObject.

Then, you need to be able to read the image from a Stream as a byte[] array and assign it:

OleDbCommand cmd = conn.CreateCommand();
cmd.CommandText = "INSERT INTO SomeTable (Name, Image) " +
  "VALUES (@Name, @Image)";
cmd.Parameters.Add("@Name", OleDbType.VarWChar, 40).Value = "ImageName";
cmd.Parameters.Add("@Image", OleDbType.Binary).Value = image;
cmd.ExecuteNonQuery();

Anonymous3-Jan-04 18:02

Anonymous

3-Jan-04 18:02

Thanks for your help

I was starting to read up on the stream. Could you give me a example how to read the image from a stream as a byte data.

I am interested in using the parameters more, as it seems to be very useful. Is there any good tutorial on them.

Many thanks in advance

Steve

Heath Stewart3-Jan-04 18:05

3-Jan-04 18:05

There's the .NET Framework SDK documentation - just type OleDbParameter in the index.

There's probably tutorials on this site and around the 'net, but they're not hard to use and the documentation offers plenty of information and examples.

Bo Hunter3-Jan-04 18:44

Bo Hunter

3-Jan-04 18:44

The OLE DB .NET Provider does not support named parameters for passing parameters to a SQL Statement or a stored procedure called by an OleDbCommand when CommandType is set to Text. In this case, the question mark (?) placeholder must be used. For example:

SELECT * FROM Customers WHERE CustomerID = ?

As a result, the order in which OleDbParameter objects are added to the OleDbParameterCollection must directly correspond to the position of the question mark placeholder for the parameter.

Thank You
Bo Hunter