Limit the length of an item in a ListView control

The ListView control doesn’t expose any property that lets you limit the amount of text users can type when editing an item’s label. However, you can do the trick with a couple of SendMessage API calls from within the BeforeLabelEdit event: with the LVM_GETEDITCONTROL message you retrieve the handle of the hidden Edit control that the ListView creates for let the user edit the node. If you then send the EM_LIMITTEXT message to this Edit control you can put a limit to the text that can be typed in this control:

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal _    hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _    lParam As Any) As LongConst LVM_FIRST = &H1000Const LVM_GETEDITCONTROL = (LVM_FIRST + 24)Const EM_LIMITTEXT = &HC5' limit the text that can be typed in ListView's item to 10 charactersPrivate Sub ListView1_BeforeLabelEdit(Cancel As Integer)    Dim editHWnd As Long    ' get the handle of the ListView's Edit control    editHWnd = SendMessage(ListView1.hWnd, LVM_GETEDITCONTROL, 0, ByVal 0&)    ' send it a EM_LIMITTEXT message to limit its length    SendMessage editHWnd, EM_LIMITTEXT, 10, 0End Sub

Once you now the method you can perform some other tricks with the Edit control. For example, you can automatically convert all text to uppercase:

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal _    hWnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _    lParam As Any) As LongPrivate Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" _    (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As LongPrivate Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" _    (ByVal hWnd As Long, ByVal nIndex As Long) As LongPrivate Const GWL_STYLE = (-16)Const LVM_FIRST = &H1000Const LVM_GETEDITCONTROL = (LVM_FIRST + 24)Const ES_UPPERCASE = &H8&' force the text typed in a ListView's node to uppercasePrivate Sub ListView1_BeforeLabelEdit(Cancel As Integer)    Dim editHWnd As Long    ' get the handle of the ListView's Edit control    editHWnd = SendMessage(ListView1.hWnd, LVM_GETEDITCONTROL, 0, ByVal 0&)    ' force the all-uppercase style    SetWindowLong editHWnd, GWL_STYLE, GetWindowLong(editHWnd, _        GWL_STYLE) Or ES_UPPERCASEEnd Sub

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