C# Discussion Boards - CodeProject

4-Mar-02 6:03

I want to create my class based on C# class (like Button, Panel or ComboBox). The wizard allows to select a base class only from my classes (not built-in classes). What I'm doing now is create a class based on nothing and then change the declaration of the class (Ex: from class MyClass {} to class MyClass :Panel {}. But my goal is to create visually class.

I also tried to create a class based on UserControl (this gives me opportunity to create visually class), where I can drop controls to this class (btw, UserControl doesn't have Dock and BorderStyle properities). But when I subclass this class again I cannot work visually. I have to do everything in the code.

Is there any way to create visually classes?

(Btw: Why, depending where the cursor is positioned, I getting different interface for creating the class. For example: when the cursor is positioned in the class view and I choose Add New Class from "Project\Add Class.." I'm getting "C# Class Wizard" (which usually crashes) where I can choose a base class. When the cursor is positioned somewhere else I'm getting "Add New Item" wizard where I cannot choose the base class.
Thanks,

Jerzy

Re: How to sublass visually a C# class

James T. Johnson4-Mar-02 14:12

James T. Johnson

4-Mar-02 14:12

You can't visually design a Control it -- by definition -- is only drawn via OnPaint and you wouldn't gain anything from visually designing because it isn't a container.

A UserControl is what you use if you want to visually design a new control. It is a container that contains other controls. Therefore a visual interface is a nice feature to use (almost required in some cases).

JerzyPeter wrote:
(btw, UserControl doesn't have Dock and BorderStyle properities).

It does have the Dock property since it inherits from Control; all Control's have the Dock property, BorderStyle doesn't exist though.

JerzyPeter wrote:
Btw: Why, depending where the cursor is positioned, I getting different interface for creating the class.

I think this is by design, this has been the case since Beta 2.

Hope I gave you some direction on what you should use for a new control.

If you want to create a class and not a control, create a new class via the the C# Class Wizard then in the class view you should be able to add methods, properties, fields, and indexers (accessing a class instance like an array).

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Re: How to sublass visually a C# class

5-Mar-02 3:19

Thanks for your answer.

1. UserControl doesn't have Dock property, it has DockPadding which determines the size of the border for docked control.

2. My problem is this: when I create UserControl with bunch of controls (buttons, labels, comboboxes) I want to be able reuse this control and create a subclasses control with extra, for example, 3 buttons, 3 lables and one slider, then I would have to do it in code instead dropping these control on my UserControl.

Anyway, thank you
Jerzy

Re: How to sublass visually a C# class

James T. Johnson5-Mar-02 7:37

James T. Johnson

5-Mar-02 7:37

JerzyPeter wrote:
1. UserControl doesn't have Dock property

It does have a Dock property, you may be confused as to when you can use it though. The Dock property is used to tell the control where it should position itself on its parent. Thus you can't see it in the property grid while you are designing the UserControl, only when you place the UserControl on a form or another UserControl will you see it.

JerzyPeter wrote:
2. My problem is this: when I create UserControl with bunch of controls (buttons, labels, comboboxes) I want to be able reuse this control and create a subclasses control with extra, for example, 3 buttons, 3 lables and one slider, then I would have to do it in code instead dropping these control on my UserControl.

I've just created a test for this and it worked. However there are some rules that you need to be aware of. When you visually inherit from a Form or a UserControl VS.NET bases the appearance on the latest build available; this can cause problems if you change both the base class and the inherited class without doing a build in-between.

Once you have your base UserControl done the way you would like, build your project/solution; this will create a compiled version of the UserControl so that you can edit the inherited class visually.

Now add another UserControl to your project, open it up in CodeView then change the line that declares your class so that inherits from the UserControl you want to base your new UserControl from. Now you should be able to open the new UserControl up in the VS.NET Forms Designer.

If you want e-mail me and I can post a quick sample showing this done on my website.

HTH,

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Re: How to sublass visually a C# class

6-Mar-02 2:44

Hi James!

Thank you very much for you answer.

I was really confused with this property Dock (because I didn't see it in design time).

If you don't mind to send me the project I would appreciate very much. (Or just explain how to visually sublcass a UserControl because I think I won't be able to figure out from the project how to do that.)

Thanks, you are a very kind person.

Jerzy
My e-mail: jerzypeter@hotmail.com

Re: How to sublass visually a C# class

James T. Johnson6-Mar-02 9:02

James T. Johnson

6-Mar-02 9:02

My SMTP server is having problems right now so I'll just post it here.

Sample Project

Here’s what I did to create the sample.

Create a new Windows Application, right click on the project in the solution explorer and choose Add UserControl, call it BaseUserControl.cs.

On the BaseUserControl set the ForeColor to the System palettes Highlight color. Resize the canvas so it is 232x40 pixels. Now add a new label control to it and place it at (8, 8) with the default size. Change the Text on the label to say “base”.

Build the project.

Now Add another UserControl to the project (right click on the project choose Add UserControl). Call it ExtendedUserControl.cs.

Now close the designer for it, right click on ExtendedUserControl in the solution explorer and choose View Code.

Now change the class declaration so that it inherits from BaseUserControl instead of System.Windows.Forms.UserControl.

public class ExtendedUserControl : System.Windows.Forms.UserControl

changes to

public class ExtendedUserControl : BaseUserControl

Build the project again. Now open up the designer for the ExtendedUserControl (double click ExtendedUserControl in the solution explorer).

When you open up the designer for the ExtendedUserControl you should see the BaseUserControl, now add another label placing it at (120, 8) with the default size. Change the Text to read “extended”.

Now click on the background of the UserControl, and set the ForeColor to the System palette’s ControlText color.

Build the project again.

Now open up Form1 by double-clicking on it in the Solution Explorer. In the toolbox you should see two new entries at the bottom; these are the new UserControls you just created. Drag one of each onto the form.

VS.NET will tell you when you make a change that requires a build for you to see it; but to be on the safe side I always do a build.

If you have any other questions feel free to ask.

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Re: How to sublass visually a C# class

6-Mar-02 10:59

Hi James!

I'm sorry but it doesn't work for me. I did everything as you did (and I was doing the same before). When I double-click ExtendedUserControl in the solution explorer I'm getting an error:

ExtendedUserControl - The base class test.BaseUserControl coud not be loaded. Ensure the assembly has been referenced or built it is part of the project.

Jerzy Confused | :confused:

Re: How to sublass visually a C# class

James T. Johnson6-Mar-02 12:42

James T. Johnson

6-Mar-02 12:42

Did you remember to build the project?

That is the error message I get when I forget to do that step.

Give my sample project a try (you'll have to build it before you can view the user controls though).

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Re: How to sublass visually a C# class

7-Mar-02 3:31

Hi James!

I'm scared to write to you again but belive me it still doesn't work for me. I'm doing exactly the same things as you.

When I open your project I can easily create another subclass of ExtendedUserCotrol.

I don't know what's going on. I tried on different machines with the same result. I was thinking maybe I have different setting in IDE. My Microsoft .NET framework is 1.0 ver. 1.0.3705, Development Environment 2002 ver. 7.0.9466

Thanks

Jerzy

Btw: I found another way of subclassing (but still only in your project): you can 'Add New Item' and choose Inherited Control and select base ExtendedUserControl for example.

Confused | :confused:

Re: How to sublass visually a C# class

James T. Johnson7-Mar-02 6:06

James T. Johnson

7-Mar-02 6:06

JerzyPeter wrote:
I'm scared to write to you again but belive me it still doesn't work for me.

Nah don't be scared, I don't bite Smile | :)

I'm curious as to why it isn't working for you when I have no problems doing it.

JerzyPeter wrote:
My Microsoft .NET framework is 1.0 ver. 1.0.3705, Development Environment 2002 ver. 7.0.9466

Same versions I'm showing. Did your box have another version of .NET on it before (one of the betas or an RC)? I repaved this one about 2 weeks ago. Funky things happen when you mix a pre 1.0 beta with the final Big Grin | :-D

JerzyPeter wrote:
Btw: I found another way of subclassing (but still only in your project): you can 'Add New Item' and choose Inherited Control and select base ExtendedUserControl for example.

Yeah, I forgot about that one. I was thinking it was only there for forms. Smile | :)

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Are ownerdrawn buttons available?

4-Mar-02 3:53

Hi all,

I was wondering if there is some way to implement ownerdraw buttons in C#.
I've searched around but didn't find anithing.

Any idea?

Thanks in advance and Kind Regards

Severino
Confused | :confused:

Re: Are ownerdrawn buttons available?

James T. Johnson4-Mar-02 14:23

James T. Johnson

4-Mar-02 14:23

This should give you a base to start from.

using System;
using System.Windows.Forms;

namespace Namespace {
  public class MyButton : Button {
    public MyButton() : base() {
      SetStyle( ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint, true );
    }

    protected override void OnPaint(PaintEventArgs e) {
      // Draw the button
    }
  }
}

HTH,

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Accessing the shell

4-Mar-02 1:51

Is there any way to access the shell in C# ?
I want to list the contents of the desktop....
Thanks! Confused | :confused:

Re: Accessing the shell

James T. Johnson4-Mar-02 14:30

James T. Johnson

4-Mar-02 14:30

Well this isn't done via the shell but you can get this list by doing this.

public string [] GetFilesOnDesktop() {
  string desktop = System.Environment.GetFolderPath( System.Environment.SpecialFolder.DesktopDirectory );
  return System.IO.Directory.GetFiles(desktop);
}

I'm not familiar with the Shell API but you should be able to also use PInvoke to call the functions you would normally.

HTH,

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Re: Accessing the shell

4-Mar-02 21:19

Thanks for the answer! I did try that, but the idea is to create a little explorer-like application in C#, with a tree listing of all contents of the desktop (the virtual directory, not the physical!).

So the question was in fact: how do I access virtual folders like desktop, my computer, my documents,...

Re: Accessing the shell

James T. Johnson4-Mar-02 22:13

James T. Johnson

4-Mar-02 22:13

Anonymous wrote:
So the question was in fact: how do I access virtual folders like desktop, my computer, my documents,...

OK, I believe the shell functions are nothing more than a COM object, so you can use the COM object via PInvoke.

Unfortunately I can't give you any more than that, PInvoke and Shell programming are both something I haven't delved into much (PInvoke) or at all (Shell programming).

I can however point you to a place that might have already answered or question, or if it hasn't been answered you can ask it there. The DOTNET mailing list is probably the best mailing list out there dealing with .NET.

Hope I pointed you in the right direction,

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Re: Accessing the shell

5-Mar-02 1:37

Thanks, great link!
However, something else.. using COM-objects, is that good programming practice...? I mean, this way you put some Windows-only code into the application, or am I wrong...?

Re: Accessing the shell

James T. Johnson5-Mar-02 8:21

James T. Johnson

5-Mar-02 8:21

Anonymous wrote:
I mean, this way you put some Windows-only code into the application, or am I wrong...?

Correct, but you'll have to use different methods for getting a list of files on the desktop for each operating system anyway. If you place all your OS specific stuff in a separate assembly then you can load the proper assembly at runtime.

FWIW I'm not sure how much of Windows.Forms is going to be ported; it isn't a part of the CLI specs but I believe the Mono project is going to port some of it over anyway.

James

Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978

Re: Accessing the shell

5-Mar-02 20:57

Okay, now I understand. Depending on the operating system, you still have to write different code.
Thank you very much for your remarks!
Kind Regards,
Ludwig

C# question

Jon Newman4-Mar-02 1:05

Jon Newman

4-Mar-02 1:05

What new system files are required to use C# apps on Win95 Win98 WinMe etc... or do they run normally using only the ordinary system files.
Basically is it worth using C# if it needs loads of extra libraries that have to be included in the installer

.NET or not .NET? MFC is the question......

Re: C# question

Michael P Butler4-Mar-02 1:25

Michael P Butler

4-Mar-02 1:25

The .NET Framework needs to be installed, about a 19mb download.

I don't think Win95 is supported as a .NET platform.

Michael Smile | :)

Re: C# question

Jon Newman4-Mar-02 1:32

Jon Newman

4-Mar-02 1:32

19meg!!! Does XP have this already? Is it in the Service packs for Win2K? Is it really worth moving to C#. Is it free to distribute on CD with a C# app?

.NET or not .NET? MFC is the question......

Re: C# question

Michael P Butler4-Mar-02 1:42

Michael P Butler

4-Mar-02 1:42

XP doesn't have it yet.
The last service pack for Win2k doesn't have it.

I don't know of any Microsoft applications or products that distribute it yet - apart from Visual Studio.

I would expect to see it in a service pack soon and probably in the next version of IE.

Michael Smile | :)

Re: C# question

Jon Newman4-Mar-02 5:55

Jon Newman

4-Mar-02 5:55

Hehe lets hope so. It also seems that .NET server has it already and will have it. On my beta it has 'The .NET Framework' however I have not dabbled in that realm as of yet.

.NET or not .NET? MFC is the question......

Magic Version 1.2 Released

3-Mar-02 21:46

The latest version of the user interface library for C# is now available. It includes source code and articles for a TabControl, Docking Windows and hand built menu code. You can achieve the VS.NET IDE look and feel quickly and easily. (And its free!)

www.dotnetmagic.com

Phil Wright
phil.wright@dotnetmagic.com

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