Re: Reference to simple types - C# Discussion Boards

Ruskin Dantra4-Dec-05 10:22

4-Dec-05 10:22

I enbaled the top most property of a child form to make it remain on the top of the application window, although not to my knowledge this set the form to be the top most of every other window as well, can anyone tell me how I can get the form to only remain on top the application window and now all the native XP windows. Thanks

Ruskin

Re: TopMost property of a form

ekynox4-Dec-05 12:42

ekynox

4-Dec-05 12:42

dont use Top Most therefore set top most property to false, set the child form's Owner property.
say
ChildForm child = new ChildForm;
child.Owner = this;

"this" implies tie it to the parent form.

Re: TopMost property of a form

Ruskin Dantra4-Dec-05 13:40

Ruskin Dantra

4-Dec-05 13:40

Thanks that helps a lot, but there is still a small problem.

Say I have a MDI container which can have several different windows within it. Say the main MDI window is 'A', it has a child window within it called 'B' and another child window called 'C'. Now window 'B' opens another small window 'D' which I want to be on top, but I only want it to be on top of 'B' and not on top of 'C', can i achieve that?

Re: TopMost property of a form

Luis Alonso Ramos5-Dec-05 6:20

Luis Alonso Ramos

5-Dec-05 6:20

I don't think you can. If you created the form by itself, and set it's Owner property to A, it would always be above A. But if you want to do that for a MDI child on another MDI child, sorry but you can't.

-- LuisR

Luis Alonso Ramos
Intelectix - Chihuahua, Mexico

Not much here: My CP Blog!

The amount of sleep the average person needs is five more minutes. -- Vikram A Punathambekar, Aug. 11, 2005

Re: TopMost property of a form

Ruskin Dantra5-Dec-05 11:38

Ruskin Dantra

5-Dec-05 11:38

Yeah I had a look around, if a form is an MDI child, and that opens another window which you want on top of the mdi child which opened it and not any other mdi child, that is not possible Frown | :(

Is there any way around so we can simulate that behaviour?

Re: TopMost property of a form

Luis Alonso Ramos5-Dec-05 15:54

Luis Alonso Ramos

5-Dec-05 15:54

Ruskin Dantra wrote:
Is there any way around so we can simulate that behaviour?

I looked around at it a little bit, and no, I can't think of anyway to simulate it. MDI was just not designed to do that. Sorry!

-- LuisR

Luis Alonso Ramos
Intelectix - Chihuahua, Mexico

Not much here: My CP Blog!

The amount of sleep the average person needs is five more minutes. -- Vikram A Punathambekar, Aug. 11, 2005

Reference to simple types

Yoyosch4-Dec-05 9:21

Yoyosch

4-Dec-05 9:21

How to get a reference to string? I mean that I want to have 2 string objects, that both point to the same string in a memory

Re: Reference to simple types

Heath Stewart4-Dec-05 19:51

Heath Stewart

4-Dec-05 19:51

A System.String (string in C#) is a reference type, so the following are equal:

string a = "Hello, world!";
string b = a;
Console.WriteLine(object.ReferenceEquals(a, b)); // Prints True

Strings are immutable, however, so as soon as you change one string - which actualy returns a copy of the string with your changes - the references are not equal. It's also important to note that string equality (the == operator) is based on the content and not the reference.

This posting is provided "AS IS" with no warranties, and confers no rights.

Software Design Engineer
Developer Division Customer Product-lifecycle Experience
Microsoft

[My Articles] [My Blog]

Collections with different classes

Mark064-Dec-05 8:03

Mark06

4-Dec-05 8:03

Hi,
I'm trying to plan abit of code for a space game and I've ground to a halt.
Here's a theory:

A Class called Object which might have some properties like Location.

Two other classes inherit this object, Planet and SpaceStation. And they their own methods and properties appropriately.

Simple so far.

Ok, so I want to create planets and spacestations and chuck them into a collection, I guess Universe.

so questions:

1) Does a class inserted into a collection always have to be exactly the same as the other existing in there?

2) If I loop through all the classes within the collection, how do I tell whether one class is a Planet or if its a SpaceStation?

Any response gratefully appreciated.

Andy

Re: Collections with different classes

Guffa4-Dec-05 9:52

Guffa

4-Dec-05 9:52

Avoid naming the class Object, or you will have to specify the full namespace every time you use it, as there is a class named Object in the System namespace.

You can either create a typed collection for objects of the base class, or use an untyped collection, like an ArrayList or a Hashtable. For a typed collection, you can use any member that you declared in the base class without type casting the objects. For an untyped collection, you have to type cast the objects to the base class or the specific class before using them.

To check the class of an object, you use the in operator:

if (anObject is Planet) {
((Planet)anObject).SomeMethod();
} else {
((SpaceStation)anObject).SomeOtherMethod();
}

---
b { font-weight: normal; }

Re: Collections with different classes

Mark064-Dec-05 10:07

Mark06

4-Dec-05 10:07

Thankyou.
Is there is any reason, or preference in using hashtables or Arraylists rather than collections?

I sort of assumed that using collections would be better to form a hierachy structure.

Such as some like....

Console.Writeline (myUniverse.SpaceObjects[0].ShipsDocked[1].ShipName.ToString())

Im guessing if I use an arraylist, then I would need to include an index field in all of my classes, to associate them to their parents?

If I'm regularly performing looping through all spaceobjects, to trigger some method for each, what would be quicker, collections or arraylists?

Or am I going down the wrong route here? Sniff | :^)

Re: Collections with different classes

Guffa4-Dec-05 14:29

Guffa

4-Dec-05 14:29

Hastable and ArrayList are collections.

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b { font-weight: normal; }

Music realtime analyser

johboh4-Dec-05 4:53

johboh

4-Dec-05 4:53

Hi there!

I have a couple of spotlights controlled from the computer, and would like to flash these in the same beat as the music I'm playing.
Therefore i need to analyse the music i play in Winamp (or if its easyier, the main mixer) and by an lowpassfilter or equal get every beat from the music.

This couldn't be to hard i guess, because there is plenty of visual plugins to winamp reacting to Music.

Writing a winamp plugin analysing the music in winamp and sending the "beats" to my C# controlling app is one way. Or?
How to write a winamp plugin? How do communicate? How do analyse the beat?

Tell me your ideas! Big Grin | :-D

----------------------------------------------
Johan Böhlin
Student at Chalmers university of technology, Sweden.
CS
johboh@student.chalmers.se
----------------------------------------------

Re: Music realtime analyser

Guffa4-Dec-05 10:10

Guffa

4-Dec-05 10:10

Check the documentation for creating plugins for winamp. I think that there already is a beat analyzer built in, at least there was one in the Advanced Visualization Studio in Windamp 2.80.

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b { font-weight: normal; }

Re: Music realtime analyser

johboh5-Dec-05 21:37

johboh

5-Dec-05 21:37

Hi there!

Do you know any "How-to: Winamp plugin in C#", or should i use google? Big Grin | :-D

----------------------------------------------
Johan Böhlin
Student at Chalmers university of technology, Sweden.
CS
johboh@student.chalmers.se
----------------------------------------------

Re: Music realtime analyser

Guffa6-Dec-05 0:54

Guffa

6-Dec-05 0:54

Have you checked on http://www.winamp.com/ ?

Otherwise go google.

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b { font-weight: normal; }

Disabling MenuItems

naglbitur4-Dec-05 4:19

naglbitur

4-Dec-05 4:19

Hi there.
I have an app that has several menus. I want that when a certain menuItem(s) is/are selected other menuItems are disabled. For instance, if a user selects menuItem2 I want menuItems 10, 12 and 17 to be disabled. How do I go about coding that?
I know about Enable = false but I don´t know how to code: if such and such menuItems are selected then such and such menuItems are to be disabled.
Thanks,

FJ

Re: Disabling MenuItems

dnewmon4-Dec-05 9:47

dnewmon

4-Dec-05 9:47

Are you talking about menu items with CheckBox's ?

Something this simple might help:
menuItem3.Enabled = (menuItem1.Checked && menuItem2.Checked && ...);

Enjoy,
David

Re: Disabling MenuItems

naglbitur4-Dec-05 10:07

naglbitur

4-Dec-05 10:07

Hi.
No, what I mean is to have a menuItem like Paste grayed out unless you have something on the clipboard, one can´t paste unless something is on the clipboard. Once you have something on the clipboard Paste becomces selectable, not grayed out. I want certain menuItems to be grayed out if some other menuItem is selected.
Thanks,

FJ

Re: Disabling MenuItems

mav.northwind5-Dec-05 3:10

mav.northwind

5-Dec-05 3:10

Hi!
You can use the menu's Popup event to enable/disable the menu items of your menu, so if you have a menu myMenu you could write the Popup event handler like this:

private void myMenu_Popup(object sender, EventArgs e)
{
  myMenuItem1.Enabled = SomeFunctionToDecideWhetherMenuItem1IsEnabled();
}

or, using the clipboard example:

private void menuEdit_Popup(object sender, EventArgs e)
{
  DataObject dob = Clipboad.GetDataObjet();
  // Only enable the Paste command if there's Text on the clipboard
  menuEditPaste.Enabled = dob.GetDataPresent(DataFormats.Text);
}

Regards,
mav

Re: Disabling MenuItems

naglbitur5-Dec-05 7:05

naglbitur

5-Dec-05 7:05

Hi, thanks for your help.
I still don´t know how to do this. How can I disable a menuItem when some other menuItem is selected? For instance, if menuItem5 is chosen then I want menuItem11 and menuItem12 to be disabled? How do I do that?
Thanks again for your help,

FJ

Re: Disabling MenuItems

mav.northwind5-Dec-05 7:18

mav.northwind

5-Dec-05 7:18

private void menuItem5_Clicked(object sender, EventArgs e)
{
  menuItem11.Enabled = false;
  menuItem12.Enabled = false;
}

that's as explicit as I can put it...

mav

Re: Disabling MenuItems

naglbitur6-Dec-05 2:06

naglbitur

6-Dec-05 2:06

Hi.
This is very clear!! Vielen Dank!
Take care,

FJ

Re: Disabling MenuItems

André Ziegler5-Dec-05 4:04

André Ziegler

5-Dec-05 4:04

Search for an ActionList component on codeproject, this should help you.

'A programmer is just a tool which converts caffeine into code'

BackgroundWorker and ProgressBar

SunsOfFun4-Dec-05 3:57

SunsOfFun

4-Dec-05 3:57

I want to display the status in a ProgressBar when copying large files across the network. I am using FileInfo.CopyTo method within the DoWork Method of the BackgroundWorker class (please see the code below). How am I able to fire events while the copying is taking place to update the ProgressBar. The problem is that the execution enters FileInfo.CopyTo method and does not leave until the process is complete.

Hope this makes sense.

private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e) {<br />
         <br />
            BackgroundWorker worker = sender as BackgroundWorker;<br />
            reached = 0;<br />
                fileInfoFrom = new FileInfo(@"C:\Temp\Path1\Test.zip");<br />
                fileInfoTo = new FileInfo(@"C:\Temp\Path2\Test.zip");<br />
<br />
               <br />
                fs = (fileInfoTo.Exists) ? fileInfoTo.Length : 0f;<br />
                fileInfoFrom.CopyTo(@"C:\Temp\Path2\Test.zip", true);<br />
                /* thought about using the file size to <br />
                 * calculate the percentage for the progressbar*/<br />
                int completed =<br />
                    (int)((float)fs / (float)fileInfoFrom.Length * 100);<br />
                if (completed > reached) {<br />
                        reached = completed;<br />
                    worker.ReportProgress(completed);<br />
                }<br />
        }

-- modified at 12:47 Sunday 4th December, 2005

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