C# Discussion Boards - CodeProject

Re: Using Reflection to walk the Object Model

Nick Parker8-Aug-04 6:24

8-Aug-04 6:24

This has been done in Reflector, what you will want to do is load the assembly, from that call GetTypes() and iterate through each type. Within each type you will want to look at classes such as MethodInfo, ConstructorInfo, FieldInfo, etc. There are methods within the Type class that will return object arrays of these types.

- Nick Parker
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Re: Using Reflection to walk the Object Model

Tony Antonucci8-Aug-04 6:43

Tony Antonucci

8-Aug-04 6:43

I would like to do this in the same code (not from an assembly). I certainly can use FieldInfo to see the root objects fields and data, but then I need to move into the contained object. Thats where I am stuck.

Type t = o.GetType();
FieldInfo[] fi = t.GetFields();
foreach (FieldInfo field in fi)
{
Console.WriteLine("Field: {0}\tType: {1}", field.Name, field.FieldType);
}

But, now....how to reflect into the "fields"?

Tony

Re: Using Reflection to walk the Object Model

leppie8-Aug-04 9:37

leppie

8-Aug-04 9:37

FieldInfo.GetValue()

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Re: Using Reflection to walk the Object Model

Anonymous8-Aug-04 10:55

Anonymous

8-Aug-04 10:55

GetValue returns an object reference. Then how to drill down into contained classes. I have had this questions too.

Re: Using Reflection to walk the Object Model

leppie8-Aug-04 11:48

leppie

8-Aug-04 11:48

Object.GetType() and u go thru the whole process again.

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Setting Property Classification - Attributes?

Tristan Rhodes8-Aug-04 3:22

Tristan Rhodes

8-Aug-04 3:22

I've got a custom control which has quite a few properties, and they are all stuck under misc.

I'm sure i read somewhere that they could be set to their own, or an already existing titled section by using an attribute, but i can't find where i read it, or any attributes which look like they might do the job.

Can anyone help me?

Cheers

Cata

Re: Setting Property Classification - Attributes?

leppie8-Aug-04 4:28

leppie

8-Aug-04 4:28

CategoryAttribute

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Managed Direct3D won't work

NhImF8-Aug-04 2:53

NhImF

8-Aug-04 2:53

I'm trying to begin programming Managed Direct3D with C#.
But whatever I do it won't work.
Not even the sample projects wich come with the SDK won't run.

The error i get is the following:
An unhandled exception of type 'System.NullReferenceException' occurred in microsoft.directx.direct3d.dll

Additional information: Object reference not set to an instance of an object.

It gives the error on the following statment:
device = new Device(0, DeviceType.Hardware, this, CreateFlags.SoftwareVertexProcessing, presentParams);

If i catch the NullReferenceException and make the program continue as if everything is fine, then i get the message that the program was unable to create a device.

I have installed the managed framework and directx.
DirectDraw seems to work fine cause i can run the sample project wich is included with: Managed DirectX Tutorial Part 1 - The Title Screen (Managed Metroid)

I'm running Windows XP sp2 rc1 with the latest Managed DirectX SDK (summer 2004) and visual studio.net 2003

Re: Managed Direct3D won't work

leppie8-Aug-04 4:30

leppie

8-Aug-04 4:30

Do you have a 3d capable graphics card? I can run all (well most, some HLSL stuff doesnt work on my hardware ATI8500) the samples here.

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Re: Managed Direct3D won't work

NhImF8-Aug-04 5:00

NhImF

8-Aug-04 5:00

Of course, else i wouln't try :P

For extra information, my system specs:
Asus A7N8X Deluxe
Amd Athlon XP 2700+
512MB ram
Hercules 3D prophet 9800 pro 128mb(an ati radeon 9800 pro)

So i dont think its a hardware problem.

Re: Managed Direct3D won't work

leppie8-Aug-04 5:25

leppie

8-Aug-04 5:25

NhImF wrote:
Hercules 3D prophet 9800 pro 128mb(an ati radeon 9800 pro)

:drool: Smile | :)

I'm not sure what the problem is then. Sorry.

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Re: Managed Direct3D won't work

Alex Korchemniy8-Aug-04 11:50

Alex Korchemniy

8-Aug-04 11:50

This is a weird problem. I'm not sure you're going to get it figured out here. Maybe you screwed the installation somewhere. Try reinstall. Make sure you have all the necessary part of the SDK installed.

Saving Time from a DataGrid

CarpyDog8-Aug-04 1:41

CarpyDog

8-Aug-04 1:41

I have a DataGrid bound to an Access 2K database

entering a time in the grid either via a DatetimePicker or directly into the
field the time displays Ok on the grid but will not update the database
using a DateTimepicker I can see that the value is a string all types in
code and XML schema are dateTime, I have saved the time back to a string
field OK

2 date/time fields formatted dd/mm/yyyy HH:mm in Access - same problem when
formatted at short time and Gener

jnc

Location is not a variable

Anonymous7-Aug-04 23:16

Anonymous

7-Aug-04 23:16

Hi I have a button named button1 on my form, and this is its evetn handler code:

private void button1_Click(object sender, System.EventArgs e)
{
	button1.Location.X += 10;
}

but compiler tells me:

Cannot modify the return value of 'System.Windows.Forms.Control.Location' because it is not a variable

Why can't we change the X and Y properties of a Point object?

Re: Location is not a variable

leppie7-Aug-04 23:33

leppie

7-Aug-04 23:33

Anonymous wrote:
Why can't we change the X and Y properties of a Point object?

Becuase a Point is a valuetype. You will need to reassign the Location to a modifeid Point object.

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Re: Location is not a variable

Anonymous8-Aug-04 0:44

Anonymous

8-Aug-04 0:44

It doesn't make sense at all! Why should we always make a new instance just to change a single property? It's really ridiculous!

Re: Location is not a variable

leppie8-Aug-04 1:36

leppie

8-Aug-04 1:36

It doesnt make sense to you, but perfectly to me! Try VB if you find C# too limiting.

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filtered error

Member 11412667-Aug-04 21:21

Member 1141266

7-Aug-04 21:21

I craete an usercontrol that have this property :

public enum enumShowState{horizantal,vertical} ;<br />
		private enumShowState m_showState ;<br />
		public enumShowState ShowState<br />
		{<br />
			get{return m_showState;}<br />
			set<br />
			{<br />
				m_showState=value;<br />
				SetShowState(value) ;<br />
			}<br />
		}

when i use it in my other project, this filtered error will be show :
Projects\mph\frmStudAnswer.cs(111): The variable 'enumShowState' is either undeclared or was never assigned.

and when i click on this error, cursor go to this source code :

public class frmStudAnswer : System.Windows.Forms.Form<br />
{<br />
	...<br />
	...<br />
	private void InitializeComponent()<br />
	{<br />
<br />
	....<br />
	...<br />
		this.UserControl1.ShowState = Share.UserControl1.enumShowState.horizantal;<br />
	... <br />
	...<br />
	}<br />
	...<br />
}

note that i referenced to my UserControl1 project.
please guide me.

Re: filtered error

leppie7-Aug-04 23:02

leppie

7-Aug-04 23:02

hd_ali@yahoo.com wrote:
this.UserControl1.ShowState = Share.UserControl1.enumShowState.horizantal;

Try not calling your instances the same names as classes (how about some proper names?). This AFAI concerned a resolution bug in C# compiler, that appears in more than one place.

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Pointers, Objects, Classes ...

Tambi Ashmoz7-Aug-04 20:36

Tambi Ashmoz

7-Aug-04 20:36

How can I get the address of an object (as IntPtr) or any other variable type ?

Though I could get a variable address in unsafe,
(or maybe there is a better c# way ... I dont know)
unsafe
{
int x=0;
int *p=&x;
}

With objects it's not working, and still I have to convert it from int* to IntPtr ...

Thanks

Re: Pointers, Objects, Classes ...

leppie7-Aug-04 23:29

leppie

7-Aug-04 23:29

And if I may ask, what do you wanna do with it?

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Re: Pointers, Objects, Classes ...

t3rmin4t0r8-Aug-04 1:50

t3rmin4t0r

8-Aug-04 1:50

GCHandle hnd = GCHandle.Alloc(object);
InPtr ptr = hnd.AddrOfPinnedObject();

But seriously what are you going to do with it ? Smile | :)

Re: Pointers, Objects, Classes ...

softp_vc8-Aug-04 18:50

softp_vc

8-Aug-04 18:50

If you are trying to read the contents of a specific address without knowing what type of data is held there, then one way of doing it is to call:

Marshal.PtrToStringAnsi(ptr, length)

where 'ptr' represents the address of the first byte and 'length' the number of bytes to be read.

This returns the data in the form of a managed string (with each byte expanded to a 2-byte unicode character), which you can then examine

Naveen

.net help for mobole computing

happyshub7-Aug-04 20:36

happyshub

7-Aug-04 20:36

i need help in dot net relating to mobile computing ..
i need to connect my server from mobile using c# and perform some functions on server from mobile..
where I can get resourses and what i need to study ........ urgent help ..

do best whereever you are...

How to set display of a column according to its value in DataGrid?

mkomasi7-Aug-04 20:02

mkomasi

7-Aug-04 20:02

Hi,
I put a DataGrid in form and I can browse the fields of a query. Now I want to show some string contents istead of numeric values of a field.
For example I have a field Enabled with (0/1) values and I want to show Enabled/Disabled instead of 0/1 numbers.
How can I do it?

Mehdi

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