Re: questions about C# - C# Discussion Boards

Re: How to make custom/own BASE classes

25-Feb-02 7:48

To use an assembly that is in the GAC you still must reference the assembly. What seems to be a pain is that you can't just reference it and let it find it in the GAC you have to specifically tell it where to look for your assembly.

What I did was I made a copy of my assembly and placed it in the same directory as my source, I then added a reference to that (using VS.NET or the /r: compiler switch). Once the code is compiled (and the assembly is in the GAC) you no longer need the local copy of the assembly.

Now when you run your code, if the assembly isn't located in the current directory it will search the GAC for it.

HTH,

James

Sonork ID: 100.11138 - Hasaki
"My words but a whisper -- your deafness a SHOUT.
I may make you feel but I can't make you think." - Thick as a Brick, Jethro Tull 1972

Felix Nielsen26-Feb-02 2:56

Felix Nielsen

26-Feb-02 2:56

Hi James,

And THX Smile | :)

(again)

It works great Smile | :)

But let's say I want to be able to add the "reference" from the GAC with VS. Even though I have added the DLL to GAC, the listbox don't have my DLL?

My question is really how do I re-distribute my application without changing to much - it would be great if xcopy and maybe GACUtil was the only task.

If I copy my DLL to the webapp's BIN folder, and add the Reference it displays a full path(URL), and If I copy the webapplication to another URL - it would fail right?

Thanks
Felix

Re: How to make custom/own BASE classes

James T. Johnson26-Feb-02 11:05

26-Feb-02 11:05

Felix Nielsen wrote:
But let's say I want to be able to add the "reference" from the GAC with VS. Even though I have added the DLL to GAC, the listbox don't have my DLL?

It seems odd, but VS.NET doesn't show assemblies that are in the GAC. Instead it shows assemblies from a few pre-defined locations. The best place to put such an assembly would be $windows_dir\Microsoft.NET\Framework\$dotnet_version\

Then VS.NET will see your assembly and add it to the list.

Now the question you need to ask yourself is "What about my assembly warrants making it available to everyone?" 9 times out of 10 there isn't really any reason to put something in the GAC. The GAC should be used for assemblies that other people/companies will want to use in their products where the size of the assembly is large enough to warrant not keeping a local version.

Felix Nielsen wrote:
If I copy my DLL to the webapp's BIN folder, and add the Reference it displays a full path(URL), and If I copy the webapplication to another URL - it would fail right?

Nope, VS.NET references everything relative to the project directory. So if you place an assembly in your bin directory the project file stores it as "bin\myAssembly.dll". If it can't find it there, it will begin a search to find it in other locations too. I don't recall what those locations are off the top of my head though.

HTH,

James

Sonork ID: 100.11138 - Hasaki
"My words but a whisper -- your deafness a SHOUT.
I may make you feel but I can't make you think." - Thick as a Brick, Jethro Tull 1972

Registry

BLaZiNiX25-Feb-02 6:34

BLaZiNiX

25-Feb-02 6:34

I'm creating a registry editor exaclty like RegEdit and I want to know how Can I retrieve Value who have DWORD and Binary type to put it in a ListView

I use Convert.ToString(...) but if I got a binary or DWORD value i got System.Byte[] or System.String[];

How can I fix this ?

questions about C#

Aaron T.25-Feb-02 4:40

Aaron T.

25-Feb-02 4:40

Hello,
My name is Aaron Thompson. I am a student at Columbus State Community College in Columbus Ohio. I am currently seeking an AAS of Computer Programming Technology, but I have just started into the world of programming, so my experience is very limited. I am currently working on a report about C#, and needed to get some primary research data. I have done a good deal of research into what C# is about, but I am still very much the novice. The report is for my Business English class, and does not have to be overly technical. I have a few questions that I have come up with, and any responses would be greatly appreciated. If possible could I have responses by Friday March 1st? If you would like to send your response to my hotmail account, it is aroconthom@hotmail.com.
If you could also leave your name and an email address for reference information that would be great. If you would not like to be referenced, your response is still very much welcomed. Thank you in advance for any help I receive.
1) What features of C# do you find to be the most useful to you when writing programs? Please list 3-5 features for your answer.
A few examples of what I would consider features of C#: The garbge collection mechanism, access to the .NET libraries for easier inheitance of code, and the ability to manage memory yourself by declaring a section of code as "unsafe".

2) What features would you consider to be the least useful to you when writting programs in C#? Please list 1-3 for your answer.

3) What previous programming languages experince do you find the most helpful when learning to use C#?
Such as profficiency with Visual Basic, C, C++, JAVA, etc.

Re: questions about C#

Anders Molin26-Feb-02 2:57

Anders Molin

26-Feb-02 2:57

Aaron T. wrote:
What features would you consider to be the least useful to you when writting programs in C#? Please list 1-3 for your answer.

Managed code/garbage collection...
No direct and easy access to the Windows API
No "real" pointers
I can't compile native applications

Aaron T. wrote:
What previous programming languages experince do you find the most helpful when learning to use C#?
Such as profficiency with Visual Basic, C, C++, JAVA, etc.

I have programming C++ for a looong time, and some years ago I also programmed in Delphi, both have been very usefull when trying out C#.
(Delphi and C# is both designed by Anders Hejlsberg, and several features in common)

- Anders

Money talks, but all mine ever says is "Goodbye!"

Re: questions about C#

Aaron T.27-Feb-02 3:23

Aaron T.

27-Feb-02 3:23

Thank you so much for your response, it will help a great deal. From everything that I have read experince in C++ will make learning C# the easiest. Doing this paper has helped me to get a direction of what areas I want to concentrate on in programming.
Have a great day,
Aaron T.

Package Application

Gavin_Mannion25-Feb-02 4:11

Gavin_Mannion

25-Feb-02 4:11

Hi All,

I have just finished creating a small application and now am trying to package it into a setup program so that I can distribute it to the people concerned.

Where is the nice easy package creator program? or what am I supposed to do now?

Thanks,

Cliff Dabrowski25-Feb-02 4:47

Cliff Dabrowski

25-Feb-02 4:47

If you are using VS 6.0 then it comes with a version of InstallShield that you can use to package your distribution.

If not then I would suggest getting a trial for any of the commercially available packages of trying the Windows MSI installer if your package warrants this complexity. Otherwise search google for shareware installer packages and give them a try. I have seen many over the years and it really depends on how complex your application is with regard to dependent components, license installation, registration, uninstall, user input and control of installation, etc.

Success is measured by ones ability to mask complexity with simplicity.

Gavin_Mannion25-Feb-02 22:00

Gavin_Mannion

25-Feb-02 22:00

Sorry forgot to mention that I am using C# and VS.NET Beta 2 (still waiting for my retail version to arrive in the UK).

I have the package installer that comes with VS 6.0 but it doesn't accept my C# project as a project?

Thanks,

26-Feb-02 13:17

Within VS.NET go to File -> Add Project -> New Project then select the Setup and Deployment option and choose Setup Project or the Setup Wizard. Follow the steps and it will create a MSI install package for you.

Re: Inherit 2 classes in c#

Gavin_Mannion26-Feb-02 21:56

Gavin_Mannion

26-Feb-02 21:56

There we go, I knew there had to be a simple smart way Smile | :)

...

You have made my day..

Cheers

Inherit 2 classes in c#

thongkk24-Feb-02 14:39

thongkk

24-Feb-02 14:39

Just wondering how to inherit 2 classes in c#?
Anyone there could provide some example code?

Confused | :confused:

Tom Archer24-Feb-02 15:31

Tom Archer

24-Feb-02 15:31

If you're referring to multiple inheritence (mi), it is not supported in C#. However, in addition to inheriting from a single class you can also inherit from as many interfaces as you like.

Cheers,
Tom Archer
Author, Inside C#

How to import C# dll dynamically

///Ansch24-Feb-02 14:11

///Ansch

24-Feb-02 14:11

Hi, I've created a C# dll using the Class library project and have a method in there that just returns a string. I'd like to import this dll in my code dynamically instead of doing the "Add reference". How would I do that? Any help would be greatly appreciated. Confused | :confused:

Peter Stephens25-Feb-02 8:04

Peter Stephens

25-Feb-02 8:04

I personally have not tried this, but this might point you in the right direction:

Try assem = System.Reflection.Assembly.Load(...) to load your assembly (C# dll).

Then t = assem.GetType(...) to get your type (class, etc.)

Then use t.InvokeMember(...) to call a method

You can also get a ConstructorInfo object through the Type object and create an instance of your class through ConstructorInfo.Invoke(...)

--
Peter Stephens

James T. Johnson25-Feb-02 8:29

25-Feb-02 8:29

*sigh* I should have reloaded the forum before I started typing my post :-P

James

Sonork ID: 100.11138 - Hasaki
"My words but a whisper -- your deafness a SHOUT.
I may make you feel but I can't make you think." - Thick as a Brick, Jethro Tull 1972

Peter Stephens25-Feb-02 10:16

Peter Stephens

25-Feb-02 10:16

Yes, but yours has better examples Big Grin | :-D

--
Peter Stephens

James T. Johnson25-Feb-02 8:27

25-Feb-02 8:27

First you use Assembly myAssembly = Assembly.LoadFrom(myDllPath); passing in the location of your dll.

Next you use the returned Assembly and search it for the Type you want to use (Type is the overlying type for all classes, enums, structs, delegates, and events). Type myType = myAssembly.GetType("myNamespace.myType");.

Now with your type you can create an instance of it. object myInstance = Activator.CreateInstance(myType);

Now comes the fun part, invoking your method!

string retVal = (string) myType.InvokeMember("MyMethodName", BindingFlags.Public | BindingFlags.InvokeMethod, null, myInstance, new object { /* any parameters here, leave empty if there are none */ } );

There you have it! You've not successfully run a method and retreived the return value.

To sum it up again,

Assembly myAssembly = Assembly.LoadFrom(/* Assembly filename/path */ myDllFilename);
Type myType = myAssembly.GetType(/* The type to load, with namespace */ myTypeName);
object myInstance = Activator.CreateInstance(/* The Type for the type to create */ myType);
string retVal = (string) myType.InvokeMember(
  /* Method name */ "myMethodName", 
  /* BindingFlags, tells what to look for */ BindingFlags.Public | BindingFlags.InvokeMethod, 
  /* The binder to use, null to use the defaul */ null, 
  /* The instance of the type to execute the method on */ myInstance, 
  /* The parameters to the method */ new object { /* Leave empty if no parameters */ }
);

HTH,

James

Sonork ID: 100.11138 - Hasaki
"My words but a whisper -- your deafness a SHOUT.
I may make you feel but I can't make you think." - Thick as a Brick, Jethro Tull 1972

///Ansch25-Feb-02 13:23

///Ansch

25-Feb-02 13:23

Thanks guys. Great help Wink | ;)

Types of exceptions

23-Feb-02 19:40

hello

is there any way to determine what exception has been thrown ?

i have a try and catch block catching Exception all the time, but id like to know what type of Exception is thrown for an object that throws one, so i know what to catch.

Re: Types of exceptions

James T. Johnson23-Feb-02 19:49