Visual Basic

Re: [VB10] Check which ListBox items are selected and which are not [modified]

3-Aug-10 12:31

Hi,

ListBox.Items contains objects of arbitrary type (i.e. Object), although most often people just store strings in there.
So you can't call methods that don't exist for those items.

However you can take advantage of SelectedItems somehow. Maybe you could iterate over all items and for each of them check if they are contained in SelectedItems, the collection has a Contains() method for that. Warning: it will trick you if you happen to store value types in the ListBox as they get boxed and will not compare-equal by default.

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

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The Mighty Atom3-Aug-10 13:01

Re: [VB10] Check which ListBox items are selected and which are not

3-Aug-10 13:01

Hmmm that actually makes sense, except for your warning. Confused | :confused:

Im gonna give it a try anyway.

Thanks to both of you.

Though if someone has a better/alternate solution, i'd like to hear about it. Smile | :)

Edit:
This is tough.

For Each Item As String In ListBox1.SelectedItems
ListBox1.SelectedItems.Contains(Item)
Next

This works but it skips over the unselected items. I need to get all the items so i can save them to a file to retrieve them later.
Hmmm, something just came up, let my try something else.

Virtual Space Shuttle Astronaut

modified on Wednesday, August 4, 2010 10:00 AM

The Mighty Atom4-Aug-10 7:14

Re: [VB10] Check which ListBox items are selected and which are not

4-Aug-10 7:14

Im having some troubles with this. Here's what i did:

First, i create a List of type string. This list only contains the selected items. This is done like so:

Dim SelectedItemsList As New List(Of String)
        For Each SelectedItem As String In ListBox1.SelectedItems
            SelectedItemsList.Add(TextBox1.Text)
        Next

Now i need to compare the List with the actual listbox list. If item exists in both the list and the listbox, then this item was selected. If its not, then it was an unselected item.

Im trouble figuring that out. How do i check that?

If SelectedItemList = ListBox.Items Then
'Selected
Else
'Not selected
End If

Something like that?

Virtual Space Shuttle Astronaut

Luc Pattyn4-Aug-10 8:12

Re: [VB10] Check which ListBox items are selected and which are not

4-Aug-10 8:12

Hi,

1.
when you reply to your own message nobody gets notified, it is only by accident that I saw this. Didn't you get a MessageBox warning you?

2.
you don't need the List at all, this should work:

For Each item As String In ListBox1.Items
    If ListBox1.SelectedItems.Contains(item) Then
        ' do something with the selected item (it should not change the ListBox)
    Else
        ' do something with the unselected item (it should not change the ListBox)
    Endif
Next

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

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The Mighty Atom4-Aug-10 8:46

Re: [VB10] Check which ListBox items are selected and which are not

4-Aug-10 8:46

I actually do get an error saying that list has changed. It also says something about an enumerator. Does'nt make sense to me.

Here's the code:

For Each item As String In ListBox1.Items
    If ListBox1.SelectedItems.Contains(item) Then
        MessageBox.Show(item & "|" & True)
    Else
        MessageBox.Show(item & "|" & False)
    End If
Next

I only get one messagebox for the first item, wether its selected or not, but then i get that error.

Confused | :confused:

Virtual Space Shuttle Astronaut

Luc Pattyn4-Aug-10 9:25

Re: [VB10] Check which ListBox items are selected and which are not

4-Aug-10 9:25

Hi,

sorry I didn't know this, it seems one cannot iterate both Items and SelectedItems like that at the same time.

I did come up with this code, which works fine:

Private Sub ListBox1_SelectedValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedValueChanged
    Dim s As String = ""
    For i As Integer = 0 To ListBox1.Items.Count - 1
        Dim item As String = ListBox1.Items(i)
        If ListBox1.SelectedItems.Contains(item) Then
            s = s & " +" & item
        Else
            s = s & " -" & item
        End If
    Next
    Label1.Text = s
End Sub

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

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The Mighty Atom4-Aug-10 9:45

Re: [VB10] Check which ListBox items are selected and which are not

4-Aug-10 9:45

There you go, that did the trick! Big Grin | :-D

I think i can figure the rest out myself (saving and loading).

Thanks, Luc! Big Grin | :-D

Virtual Space Shuttle Astronaut

Luc Pattyn4-Aug-10 11:42

Input data set changed dynamically according to option selection in VB.net 2005

4-Aug-10 11:42

You're welcome.

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

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Andraw Tang2-Aug-10 12:03

Andraw Tang

2-Aug-10 12:03

Hi, dear all,

I have a project created in VB.net 2005 and I will collect some user input data based on user selection for calculation.
Since the input data number and content are different based on user selection, I have problem about how to layout these input fields.

For example, the SpeedContrlType is a combobox with value 1,2 and 3, for different value, the set of input data is totall different. If user select value 1, I will show data for type 1 and hide data for other 2 types, same for type 2 and 3.

Can you give me some suggenstion how to organize the form for this case? I don't want to show all data at the same time, then if user select type 1, enable type 1 data set and disable other two sets.

Thanks a lot!

Re: Input data set changed dynamically according to option selection in VB.net 2005

Eddy Vluggen3-Aug-10 10:55

Eddy Vluggen

3-Aug-10 10:55

Andraw Tang wrote:
Can you give me some suggenstion how to organize the form for this case? I don't want to show all data at the same time, then if user select type 1, enable type 1 data set and disable other two sets.

The easiest option is to put the UI for each type into Panel. Hide panels number 2 & 3 by default, and switch visibility if the user changes the type.

A better choice would be to move it to a UserControl Smile | :)

I are Troll Suspicious | :suss:

Re: Input data set changed dynamically according to option selection in VB.net 2005

Andraw Tang4-Aug-10 3:49

Andraw Tang

4-Aug-10 3:49

Eddy,

Thank you for your reply.

If I use panels to hold data, I should overlap these panels and make one of them visible according to user selection, right?

What did you mean to move it to UserControl? I am new to VB.net, can you give me more explanation? it's best if you can give me some sample.

Thanks again!

Re: Input data set changed dynamically according to option selection in VB.net 2005

Eddy Vluggen4-Aug-10 4:21

Eddy Vluggen

4-Aug-10 4:21

Andraw Tang wrote:
If I use panels to hold data, I should overlap these panels and make one of them visible according to user selection, right?

Yup. It would be easier to put them next to each other in the designer, and to move them to the correct location when the form is loaded.

Andraw Tang wrote:
What did you mean to move it to UserControl?

A UserControl resembles a blank panel, and is used if you need to build your own controls. Imagine that you're using a Panel over and over again to display a picture and the name of the user. You could copy/paste that code and the panel, or you could create a new control;

VB.NET

Public Class MyPanel
    Inherits System.Windows.Forms.UserControl
		
    Public Name As String
		
End Class

This new control can contain anything you like. There's a walkthrough[^] on MSDN if you want to give it a try Smile | :)

I are Troll Suspicious | :suss:

Re: Input data set changed dynamically according to option selection in VB.net 2005

Andraw Tang4-Aug-10 4:39

Andraw Tang

4-Aug-10 4:39

Eddy,

Thanks, I will take a look.

data access sample project

soulrebelpd2-Aug-10 11:05

soulrebelpd

2-Aug-10 11:05

I'm moving from Ms Access to vb.net/Sql Server. I'm looking for a sample project that includes a vb.net front end and Sql Server back end. There is plenty of sample code out there, but I havn't found any complete applications.

Yusuf2-Aug-10 12:48

Yusuf

2-Aug-10 12:48

I'm not sure if you can find complete application, but there are plenty sample codes. What is wrong with sample codes? Roll eyes | :rolleyes:

Yusuf
May I help you?

soulrebelpd2-Aug-10 13:50

soulrebelpd

2-Aug-10 13:50

I'm very new to programming, and I'm probably not much of a natural at it, although I enjoy it thoroughly. I learned what I know about Ms Access from "reverse engineering" an application(as well as reading books of course).

I just purchased a book Murach's ado.net vb2008, it has a good amount of sample applications so hopefully it will help.

Yusuf2-Aug-10 14:39

Yusuf

2-Aug-10 14:39

soulrebelpd wrote:
I learned what I know about Ms Access from "reverse engineering" an application(as well as reading books of course).

I'm not sure how much you can learn from reverse engineering alone. Not to mention the amount of time you will spend in understanding the code.

soulrebelpd wrote:
I just purchased a book Murach's ado.net vb2008, it has a good amount of sample applications so hopefully it will help.

Good for you. Books are good source of information. Also consider taking a class. It may accelerate your learning curve.

Yusuf
May I help you?

Simon_Whale3-Aug-10 0:08

Simon_Whale

3-Aug-10 0:08

sample applications from msdn

this might be a good place to start Smile | :)

As barmey as a sack of badgers