Visual Basic - How to determined the index of a item in ListView

Question

I have determined the item in a listview that I with to remove (by searching by way of my code).  Now I would like to determined the index of that item so I can use removeat(index) to remove the item.  How do I determined the index? or can I remove that item without knowing the index?  Please help.

Ed.

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ecb

Answer 1

Ed,

Have a look at something I posted yesterday morning here:

http://social.msdn.microsoft.com/Forums/en-US/vbgeneral/thread/567c01b3-496c-4a44-9414-989461025beb/#858310bc-caad-4081-a977-73bc24b9eb2b

It's the last reply if that doesn't open correctly. In it, you'll see that I have a ListView and the user has clicked the "Remove" button and I remove that item based not on the index, but on the item they've chosen (i.e., the one in the collection of the SelectedItems).

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Please call me Frank :)

Answer 2

Let me try that again - that's why I shouldn't "edit code on the fly" here:

    Private Sub btn_RemoveFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
        Handles btn_RemoveFile.Click
        '
        If ListView1.SelectedItems.Count > 0 Then
            ListView1.BeginUpdate()
            '
            For i As Integer = ListView1.Items.Count - 1 To 0 Step -1
                If ListView1.Items(i).Selected Then
                    Dim lvi As ListViewItem = ListView1.Items(i)
                    ListView1.Items.Remove(lvi)
                End If
            Next
            '
            ListView1.EndUpdate()
        End If
        '
    End Sub

Do you see why I have to go through the list in reverse order?

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Please call me Frank :)

Answer 3

I won't be online tonight much longer, so let me answer my own question:

When you tell it to start at the top and look to the bottom (i.e., For i As Integer = 0 To ListView1.Items.Count - 1), then you can't change anything that will alter that bottom-most index number. If you think about it, that just makes sense. Let's say I had ten items (index 0 through 9) and I remove one. Now there IS not item at index 9, right?

That's why it will throw an exception.

On the other hand, if you tell it to start at the bottom and look to the top, it doesn't look behind it - it's looking to the top (index 0) which you didn't change. That's why that second method works.

Another way would be to create a temporary collection (ergo, a list of ListViewItems) and then remove them. You're not in the collection of ListView items when you do that so no harm. And to throw in yet another way, you could also create a temporary List(Of Integer) and go through the list like I showed and, if the item is selected, add that index number to the List(Of Integer).

Now go through that list and use .RemoveAt(i) ... that would work also.

I'll look back in here in the morning but I hope this has helped some.

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Please call me Frank :)

Answer 4

OK, Maybe I did not pose the question correctly.  I am not talking about any one clicking a button to determined the item to be remove.   My written code is searching the listview to determined what entry to remove.  Once my code has determined the item to be remove how do I get the index number of the item?  No button click.

Ed.

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ecb

Answer 5

Maybe you could post your code so we could see how it determines what Item is to be removed and then provide you with an answer of how to find the index number.

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You've taught me everything I know but not everything you know.

Answer 6

Public Class Form1

    Dim LViewToDelete As Integer = 10000000

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        ListView1.AllowColumnReorder = True
        ListView1.GridLines = True
        ListView1.View = View.Details
        ListView1.Sorting = SortOrder.Ascending

        ListView1.Columns.Add("Instance", 200, HorizontalAlignment.Left)
        ListView1.Columns.Add("Instance Nr 1", 200, HorizontalAlignment.Left)
        ListView1.Columns.Add("Instance Nr 2", 200, HorizontalAlignment.Left)
        ListView1.Columns.Add("Instance Nr 3", 200, HorizontalAlignment.Left)

        Dim item1 As New ListViewItem("1st instance")
        item1.SubItems.Add("1st instance 1")
        item1.SubItems.Add("1st instance 2")
        item1.SubItems.Add("1st instance 3")
        ListView1.Items.AddRange(New ListViewItem() {item1})

        Dim item2 As New ListViewItem("2nd instance")
        item2.SubItems.Add("2nd instance 1")
        item2.SubItems.Add("2nd instance 2")
        item2.SubItems.Add("2nd instance 3")
        ListView1.Items.AddRange(New ListViewItem() {item2})

        Timer1.Interval = 2000
        Timer1.Start()

    End Sub

    Private Sub ListView1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListView1.SelectedIndexChanged

    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs)
        ListView1.FindItemWithText(TextBox1.Text).Index.ToString()
    End Sub

    Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
        
    End Sub

    Private Sub TextBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles TextBox1.KeyDown

        If e.KeyCode = Keys.Enter Then
            Try
                LViewToDelete = CInt(ListView1.FindItemWithText(TextBox1.Text).Index.ToString())
            Catch ex As Exception
            End Try
            If LViewToDelete <> 10000000 Then
                Try
                    ListView1.Items.RemoveAt(LViewToDelete)
                Catch ey As Exception
                End Try
            End If
        End If
        LViewToDelete = 10000000

    End Sub

End Class

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You've taught me everything I know but not everything you know.

Answer 7

Subitems is not a member of ListView1.

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You've taught me everything I know but not everything you know.

Answer 8

Ed,

That is probably no true code, from1?????????????????????????????????

However, I've written this in this forum endless times, people want for some reason use a listview like a DataGridView, that goes wrong as soon as you start doing the things you want to do.

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Success
Cor

Answer 9

you can try just few lines:

        Dim ListItem As ListViewItem = listView1.FindItemWithText("test")

        Dim index As Integer = ListItem.Index

        listView1.Items.RemoveAt(index)
' ------------OR------------
        listView1.Items.Remove(ListItem)

thanks

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Hirendra Sisodiya from authorcode.com

Answer 10

Monkeyboy,  this is the code that locate the item I wish to remove from the listview.  I am working with two listviews and I have already removed the item from the first listview and I wish to keep them in synch.

For each LVI2 as listviewitem in form1.listview1.items

If LVI.text = LVI2.text and _

   LVI.subitems(1).text = LVI2.subitems(1).text and _

   LVI.subitems(2)text  = LVI2.subitems(2).text then    '   <=== here I get my match of both items

   from1.listview1.items.removeat(XXXXXXXX)     ' <=== here is where I need the index number to remove the item

Unless I can remove it without the index.    I am new in Visual Basic.

Ed.

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ecb

Ed,

There's nothing wrong with using For Each, but if you do then you'll need to come up with your own counter. As an example:

Dim idx As Integer = 0

For Each lvi As ListViewItem In MyListView.Items
   'Make your comparison and if true use Exit For here
   idx += 1
Next

Now the integer idx is the index. Another way you could do it would be:

Dim idx As Integer = 0

For i As Integer = 0 To MyListView.Items.Count - 1
   ' Make your comparison and if true do the following
   idx = i
   Exit For
Next

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Please call me Frank :)

Answer 11

Ed,

That is probably no true code, from1?????????????????????????????????

However, I've written this in this forum endless times, people want for some reason use a listview like a DataGridView, that goes wrong as soon as you start doing the things you want to do.

The ListView and DataGridView serve different purposes.  Use a DataGridView for displaying data from a bound data base.  Use a ListView for unbound data.  The ListView is simpler and easier to use for unbound data.

Answer 12

The ListView and DataGridView serve different purposes.  Use a DataGridView for displaying data from a bound data base.  Use a ListView for unbound data.  The ListView is simpler and easier to use for unbound data.

John,

That was my idea in past also, but in fact is the DataGridView a kind of combination between the older MSFlexGrid and the DataGrid.

Both are not completely done in the DataGridView by the way, but the DataGridView works perfectly even using the designer with unbound data.

The listview is for me currently only good usable with all kind of files, because those can then be displayed as image, tile, list, detailed or even more inside the listview; And are as item easily to copy to the clipboard.

If it is to show data bound or unbound the datagridview does a better job.

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Success
Cor

Answer 13

OK, problem solved.  It work.

Ed.

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ecb