WinForms ListView Find & GetSubItemRect

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Introduction

Do you want to find an Item in a ListView control without writing a loop to search through the Items collection? Do you need to get the bounding rectangle of an Item or SubItem (in Details view) in a ListView control? Well then, this article is for you!

Background

VB 6 supports a Find() method to find an Item in a ListView control. However, this method is no longer present in VB.NET. So you could write a code to loop through the Items collection, comparing each Item's text with your search text, e.g.:

For Each itm As ListViewItem In ListView1.Items
    If exactMatch Then
       If itm.Text = mySearchText Then
          ' an exact match was found ...
       End If
    Else
       mySearchText &= "*"
       If itm.Text Like mySearchText Then
          ' a partial match was found ...
       End If
    End If
Next

where mySearchText is the text you are searching for, and exactMatch is a Boolean you've defined to determine if an exact or partial match is to be made. Also, although the ListView Item supports the GetBounds() method to return a rectangle with the bounds of the ListView Item, e.g.:

myRect = ListView1.Items(0).GetBounds(ItemBoundsPortion.Entire)

Unfortunately, ListView SubItem does not, so:

myRect = ListView1.Items(0).SubItems(1).GetBounds(ItemBoundsPortion.Entire)

produces the following error:

'GetBounds' is not a member of 'System.Windows.Forms.ListViewItem.ListViewSubItem'.

Using the code

To use the LVFindItem class, add a new class to your project and replace the generated code with the contents of LVFind.vb. Then, in the code for your form containing a ListView control, add a code similar to the following.

To search for a string in the ListView Items collection:

Dim fPar As Integer = LVFind.LVFindItem.LVFI_PARTIAL
Dim mySearchString As String = "findme"
...
Sub Find()
   FindIt(mySearchString, fPar)
End Sub
...
' Search for SearchString in ListView1 Items
Private Sub FindIt(ByVal SearchString As String, _
 Optional ByVal flag As Integer = LVFind.LVFindItem.LVFI_PARTIAL)
   ' Make an instance of the LVFindItem class
   Dim lvf As New LVFind.LVFindItem
   ' Call the LVFnd() sub
   '   1st parm is ListView control
   '   2nd parm is text to find
   '   3rd parm (optional) is flag value (see LVFindItem class for definition)
   lvf.LVFnd(ListView1, SearchString, flag)
   ' Focus the ListView control so we can see which item is selected
   ListView1.Focus()
End Sub

To get the bounding rectangle of a ListView Item or SubItem:

Dim itmIdx As Integer = 1 ' The index of the Item in the Items collection
Dim colNum As Integer = 2 ' The column of the Item or SubItem
Dim myRect As Rectangle ' Holds the return value from Locate()
...
Sub GetRect()
   myRect = Locate(itmIdx, colNum)
End Sub
...
'Get bounding rectangle of Item itm, Column col
Private Function Locate(ByVal itm As Integer, ByVal col As Integer) As Rectangle
   ' Make an instance of the LVFindItem class
   Dim lvf As New LVFind.LVFindItem
   ' A new Rectangle to hold the return value from GetSubItemRect
   Dim rect As New Rectangle
   ' Call the GetSubItemRect() function
   '   1st parm is ListView control
   '   2nd parm is index of Item to find
   '   3rd parm is column of SubItem to find
   '   4th parm (optional) is flag value (see LVFindItem class for definition)
   rect = lvf.GetSubItemRect(ListView1, itm, col, LVFind.LVFindItem.LVIR_LABEL)
   Return rect
End Function

Points of Interest

Interestingly, on MSDN, under the definition of the LVM_GETSUBITEMRECT message, the definition of the LVIR_LABEL flag value states that it is identical to LVIR_BOUNDS. This is incorrect, at least when the ListView control is in Details view. Try changing the flag's value in the LVFind test code (hint: I'm already using LVIR_LABEL, so change it to LVIR_BOUNDS and give it a try).

History

23^rd Jan 2005 - First release.