How to search in listview - vb.net

Question

I am trying to create a Loop that will read through the information on my ListView through the SubItem to find the text that matches the text in my Textbox whenever I hit the search button and Focuses the listbox onto the matched text. Below is what I have but it keeps telling me that the value of string cannot be converted. I am also pretty sure that my numbers wont loop correctly but I am not really sure how to cause them to loop endlessly till end of statement.
Dim T As String
T = Lines.Text
For r As Integer = 0 to -1
For C As Integer = 0 to -1
If List.Items(r).SubItems(C).Text = Lines.Text Then
List.FocusedItem = T
End If
Next
Next
End Sub

Answer 1

I don't understand your code, but I do understand the question. Below is example code to search all rows and columns of a listview. Search is case insensitive and supports a "find next match" scenario. If a match or partial match is found in any column the row is selected. TextBox1 gets the text to find. FindBtn starts a new search.
Private SrchParameter As String = ""
Private NxtStrtRow As Integer = 0
Private Sub FindBtn_Click(sender As Object, e As EventArgs) Handles FindBtn.Click
If Not String.IsNullOrWhiteSpace(TextBox1.Text) Then
SrchParameter = TextBox1.Text
NxtStrtRow = 0
SearchListView()
End If
End Sub
Private Sub ListView1_KeyDown(sender As Object, e As KeyEventArgs) Handles ListView1.KeyDown
If e.KeyCode = Keys.F3 Then
SearchListView()
End If
End Sub
Private Sub SearchListView()
' selects the row containing data matching the text parameter
' sets NxtStrtRow (a form level variable) value for a "find next match" scenario (press F3 key)
If ListView1.Items.Count > 0 Then
If SrchParameter <> "" Then
Dim thisRow As Integer = -1
For x As Integer = NxtStrtRow To ListView1.Items.Count - 1 ' each row
For y As Integer = 0 To ListView1.Columns.Count - 1 ' each column
If InStr(1, ListView1.Items(x).SubItems(y).Text.ToLower, SrchParameter.ToLower) > 0 Then
thisRow = x
NxtStrtRow = x + 1
Exit For
End If
Next
If thisRow > -1 Then Exit For
Next
If thisRow = -1 Then
MsgBox("Not found.")
NxtStrtRow = 0
TextBox1.SelectAll()
TextBox1.Select()
Else
' select the row, ensure its visible and set focus into the listview
ListView1.Items(thisRow).Selected = True
ListView1.Items(thisRow).EnsureVisible()
ListView1.Select()
End If
End If
End If
End Sub

Answer 2

Instead of looping like that through the ListView, try using a For Each instead:
searchstring as String = "test1b"
ListView1.SelectedIndices.Clear()
For Each lvi As ListViewItem In ListView1.Items
For Each lvisub As ListViewItem.ListViewSubItem In lvi.SubItems
If lvisub.Text = searchstring Then
ListView1.SelectedIndices.Add(lvi.Index)
Exit For
End If
Next
Next
ListView1.Focus()
This will select every item which has a text match in a subitem.
Don't put this code in a form load handler, it won't give the focus to the listview and the selected items won't show. Use a Button click handler instead.

Answer 3

This is the easiest way to search in listview and combobox controls in vb net
dim i as integer = cb_name.findstring(tb_name.text) 'findstring will return index
if i = -1 then
msgbox("Not found")
else
msgbox("Item found")
end if