Windows Forms

20-Aug-07 21:53

Hy there. I have a big problem with a listbox, wich I want to fill with some strings(they represent file paths). And I want to validate not the listbox, but those strings in the listbox, so how can I tell the user he can't change focus from one string to another without doing some particular thing?

If I add to the listbox something other than a string, the listbox doesn't know how to draw them, and I don't want to add controls to the listbox.

The big problem is that the event selectedindexchanged is fired after the index actually changed..so i don't know the last selectedindex Frown | :(

If anyone can help..PLEASE

Toma Catalin,programmer

Luc Pattyn20-Aug-07 22:54

20-Aug-07 22:54

Hi,

1.
you can store all kinds of objects in a ListBox; by default it paints its ToString()
result. You can draw the items yourself by setting another DrawMode, then handle
the DrawItem (and optionally MeasureItem) event.

2.
You can add one class member to remember the previous selection; it suffices
to end your SelectedIndexChanged handler on
"myListBoxPreviousSelectedIndex=myListBox.SelectedIndex;"
so it is available the next time that event fires.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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ctoma200522-Aug-07 4:17

22-Aug-07 4:17

I already choosen the second solution..it works, but me ego is hurt:P
If it really paints its tostring() method, then why if I add an textbox, it doesn't paint anything?

Luc Pattyn22-Aug-07 4:34

22-Aug-07 4:34

I am not sure what myTextBox.ToString() should return.
Most .NET classes return their type string.
A simple experiment showed it returned the first line of text.

If you forgot to add any text, or you added text starting with \n
then I guess nothing would show.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

ctoma200524-Aug-07 0:49

Re: big problem: Validating the items in a listbox [modified]

24-Aug-07 0:49

Damn, i can't understand, in my app it doesn't show nothing.
My code looks like this:

<br />
public class MyTextBox : TextBox<br />
    {<br />
        public override string ToString()<br />
        {<br />
            return Text;<br />
        }<br />
    }<br />
    public partial class Form1 : Form<br />
    {<br />
        public Form1()<br />
        {<br />
            InitializeComponent();<br />
            MyTextBox x = new MyTextBox();<br />
            x.Text = "aaa";<br />
            listBox1.Items.Add(x);<br />
        }<br />
    }<br />

My listbox is blank after this.. If it would show "aaa", now all i would have to do is add an validating event and my job is finished. I'm doing something wrong?

Luc Pattyn24-Aug-07 1:46

24-Aug-07 1:46

How many textboxes are there ? if more than one,
which one is shown on the form (i.e. added to Form.Controls)?
and which one is given some text?

[EDIT]
Sorry, that would be wrong I think.

Did you try a listbox1.Invalidate() ?
I am afraid changing a control inside a ListBox might not cause a repaint,
I don't expect it to react as a Container...
[/EDIT]

Smile | :)

-- modified at 7:53 Friday 24th August, 2007

-- modified at 7:54 Friday 24th August, 2007

Luc Pattyn [Forum Guidelines] [My Articles]

ctoma200524-Aug-07 3:26

24-Aug-07 3:26

Well i find out how many there are at runtime.
Let me tell you exactly what I want. I have an directory servers wich contains a lot of dirs (I find out how many at runtime). All I want from them to add to the listbox is their names. I don't necessarly want a listbox, but I tought of a listbox because it looks good. The client needs to change between this dirs but I don't want to let him do that if some settings are changed(I wan't to ask him if he wants to change them). So I just want to validate what is in that listbox. If I add them to the listbox as objects, thei don't have a validating and focus. If I add them as controls, they have what I need but they loose their aspect, because it doesn't draw them like it would do for strings (for strings it looks exactly like I want)

Luc Pattyn24-Aug-07 3:39

24-Aug-07 3:39

Hi,

AFAIK the items in a listbox don't fire any events, so putting a textbox in there
does not result in TextChanged or whatever event since the textbox is not part of
your Form.Controls or ListBox.Controls

As I said before, you can choose what kind of objects you add to a ListBox.
If you are not happy by the text that gets shows, simply override the object's ToString()
method.

Two questions:
What is it the user must do when he has selected an item ?
Did you try the Invalidate() I suggested?

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

ctoma200524-Aug-07 4:02

24-Aug-07 4:02

The user sees settings for each individual server, when he chooses one. But if he changes this settings, i don't want to loose the last servers settings, so i want to ask him if he wants to save them.
I did override the tostring() method and i still don;t see nothing on screen, but the items are there, since the listbox lets me choose from them.
I repeat, i don't know if i choosen the right control(listbox), I just wan't the client to see a lot of names( server names) and if he chooses one of them, he can change server settings. If I add the controls to the form directly, i loose a lot of support(scroll suport if there are many servers, and when i choose one of them it doesn't look as good as it would in a listbox)

Luc Pattyn24-Aug-07 4:17