[RESOLVED] VB.Net Newbie - Listview Questions

[Mark Gambo]

I finally am going to make a concerted effort to learn VB.Net. So I installed VB.Net 2005 Express on my machine and away I go. I think the best way for me to learn how to program in VB.Net is to do it in small bits. I decided to start with the Listview. I want to learn how to use a listview and to do it properly meaning using it the way it is suppose to be used. Please take a look at my code and let me know how I can improve it.

Public Class Form1
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'TODO: This line of code loads data into the 'FrontDataSet.Copy_of_Features' table. You can move, or remove it, as needed.
        Dim a As Integer
        With ListView1
            .View = View.Details
        End With
 
        Call lvwInitialize(ListView1)
        Call DoTheChart()
        Call ResizeForm()
    End Sub
 
 
    Private Sub lvwInitialize(ByVal lvw As ListView)
        Dim lvh As ColumnHeader
        Dim a As Integer
 
        With lvw
            .Clear()
            .FullRowSelect = True
 
            With .Columns
                For a = 1 To 3
                    lvh = .Add("Column " & a)
                    lvh.Width = lvw.Width / 3
                Next a
            End With
        End With
 
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Call LoadData(ListView1)
    End Sub
 
    Private Sub LoadData(ByVal lvw As ListView)
        Dim lvi As ListViewItem
        Dim i As Integer
        Dim a As Integer
 
        With lvw
            .FullRowSelect = True
            .View = View.Details
            .Items.Clear()
 
            For i = 0 To 10
                lvi = New ListViewItem()
                lvi.Text = String.Format("Col1-Row{0}", i)
 
                For a = 1 To .Columns.Count
                    lvi.SubItems.Add("") '<=== Why do I need this line?
                    lvi.SubItems(a).Text = String.Format("Col" & a & "-Row{0}", i)
                Next a
 
                .Items.Add(lvi)
            Next i
        End With
 
    End Sub
 
    Private Sub ResizeForm()
        Dim lvw As ListView
        Dim lvh As ColumnHeader
        Dim a As Integer
 
        lvw = ListView1
 
        If Me.WindowState = FormWindowState.Minimized Then Exit Sub
 
        With lvw
            .Top = 0
            .Left = 0
            .Width = ClientSize.Width - 10
            .Height = (ClientSize.Height) - 30
 
            With .Columns
                For a = 0 To .Count - 1
                    lvh = .Item(a)
                    lvh.Width = lvw.Width / 3
                Next a
            End With
        End With
 
        With Button1
            .Top = ClientSize.Height - .Height - 5
        End With
    End Sub
 
    Private Sub Form1_Resize(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Resize
        Call ResizeForm()
    End Sub
 
End Class

Thanks!

[vbdotnetboy]

well for one with the resize function all you have to do is set the listviews anchor or dock properties then adjust the column widths

same with the button

[Mark Gambo]

well for one with the resize function all you have to do is set the listviews anchor or dock properties then adjust the column widths

same with the button

I can't believe how easy that was! I used the Dock Property but I was unable to size the listview by using the Anchor Property, could you show me how?

Thanks

[vbdotnetboy]

Private Sub LoadData(ByVal lvw As ListView)
        Dim lvi As ListViewItem
        Dim i As Integer
        Dim a As Integer
 
        With lvw
            .FullRowSelect = True
            .View = View.Details
            .Items.Clear()
 
            For i = 0 To 10
                lvi = New ListViewItem()
                lvi.Text = String.Format("Col1-Row{0}", i)
 
                'Do this instead
                For a = 1 To .Columns.Count
                    lvi.SubItems.Add(String.Format("Col" & a & "-Row{0}", i))
                '    lvi.SubItems(a).Text = String.Format("Col" & a & "-Row{0}", i)
                Next 
 
                .Items.Add(lvi)
            Next i
        End With
 
    End Sub

[techgnome]

You set which sides you want it anchored from (default is left, top) then as the form is resized, the LV edges will stay that same distance from the form's edges.

-tg

[Mark Gambo]

You set which sides you want it anchored from (default is left, top) then as the form is resized, the LV edges will stay that same distance from the form's edges.

-tg

Thanks for the post! So when I set the Anchor property which should take care of the Top and Left properties I still have to size the width and height?

[vbdotnetboy]

docking the control to either top, right, left, bottom, or fill will place it in that area. meaning for instance you dock to the top it would be placed in the top of a form or container control and would be the width of the listview owner control you could still set the height of the listview. this is the same with docking it to the bottom.
if you dock to the right or left then the control is expanded on the y-axis instead of the x, meaning you can play with the width of the control.
if you us fill the control does just what the property says... it fills the parent control on both the x and y-axis.

anchor on the other hand, is a nice featrue for resizing controls.

lets say you have a form that is 800x600
a listview that is 300x200
at an x/y of 100/50

you want it to stay at the 100/50 x/y but when you maximize the form you want the control to grow. so you would set the anchor properties to left, top, right, and bottom... that is if you want it to expand both on the x and y. if you only would want the x it would be left, top, and right. us the IntelliSense to get the exact enumerator

[techgnome]

Step by step:
1) Toss in a new form (blank)
2) Plop a LV on it
- run it and resize the form.... no matter what you do the upper left of the LV stays put
-stop the app
3) Find the Anchor property for the LV. Change it FROM Top, Left to Bottom, Right
- run the app again and resize the form... now the LV will "Stick" to the bottom right corner
-stop the app
4) Change the Anchor to Top, Left, Right
-Run the app again and resize the form
-Repeat ad nauseum to see how the different combinations of top, left, bottom & right work.

-tg

edit: I should mention that this example is with the Docking off... but it can also be retried w/ docking on to see how it works with it and effects things as well.

[Mark Gambo]

. . . 
                'Do this instead
                For a = 1 To .Columns.Count
                    lvi.SubItems.Add(String.Format("Col" & a & "-Row{0}", i))
                '    lvi.SubItems(a).Text = String.Format("Col" & a & "-Row{0}", i)
                Next 
. . .

Thanks for the help, I have implemented your suggestions. I put an Image list on the form and I loaded it with images but when I run the program the icons don't change. Here is my code:

Private Sub LoadData(ByVal lvw As ListView)
        Dim lvi As ListViewItem
        Dim i As Integer
        Dim a As Integer
 
        With lvw
            .FullRowSelect = True
            .View = View.Details
            .SmallImageList = Me.ImageList1
            .Items.Clear()
 
            For i = 0 To 10
                lvi = New ListViewItem()
                lvi.Text = String.Format("Col1-Row{0}", i)
 
                For a = 1 To .Columns.Count
                    lvi.SubItems.Add(String.Format("Col" & a & "-Row{0}", i))
                    lvi.ImageIndex = a + 5
                Next a
 
 
                .Items.Add(lvi)
            Next i
        End With
 
    End Sub

[vbdotnetboy]

well before i answer and possiblly make myself out to be a fool where do you want the images to appear?

[Mark Gambo]

well before i answer and possiblly make myself out to be a fool where do you want the images to appear?

Adjcent to each row.

[vbdotnetboy]

ok i see the problem... think about it each time the loop end it's the same value therefore your imagelistindex is always going to whatever (x) would be x = a + 5... you would want it in the first loop

[vbdotnetboy]

i taking a guess but did you want the image next to each subitem?

[Mark Gambo]

ok i see the problem... think about it each time the loop end it's the same value therefore your imagelistindex is always going to whatever (x) would be x = a + 5... you would want it in the first loop

D'uh, I can't believe I did that , Thanks!

[vbdotnetboy]

no problem

[Mark Gambo]

Here is the updated code, just in case anyone was interested:

Private Sub LoadData(ByVal lvw As ListView)
        Dim lvi As ListViewItem
        Dim i As Integer
        Dim a As Integer
 
        With lvw
            .FullRowSelect = True
            .View = View.Details
            .SmallImageList = Me.ImageList1
            .Items.Clear()
 
            For i = 0 To 10
                lvi = New ListViewItem()
                lvi.Text = String.Format("Col1-Row{0}", i)
                lvi.ImageIndex = I
 
                For a = 1 To .Columns.Count
                    lvi.SubItems.Add(String.Format("Col" & a & "-Row{0}", i))
                Next a
 
                .Items.Add(lvi)
            Next i
        End With
 
    End Sub