A “Visual Cue” Textbox

Kevin Ragsdale

January 08, 2013

This is a textbox control inspired by the Search box in Windows Explorer:

I think this type of control would be useful in several different scenarios:

For a Search box (as shown in the image above)
When you don’t have enough screen real estate for a label and textbox together
When you want to display the format mask for the box

We’ll start off with a basic textbox control (subclassed from the Visual FoxPro TextBox base class):

DEFINE CLASS txttextbox AS textbox
   FontName = "Segoe UI"
   Height = 23
   Width = 100
   IntegralHeight = .T.
   Name = "txttextbox"

   PROCEDURE Init
      ** Are we running a pre-Vista version of Windows?
      IF VAL(OS(3)) < 6 && Windows Pre-Vista
         ** Set the default font to Tahoma. Plus,
         ** if the font size is set to the Vista
         ** default (9pt), set it to 8pt. If it is not
         ** the default, let's make it 1pt smaller.
         This.FontName = "Tahoma"
         This.FontSize = IIF(This.FontSize=9,8,This.FontSize-1)
      ENDIF
   ENDPROC

   PROCEDURE RightClick
      DEFINE POPUP shortcut SHORTCUT RELATIVE FROM MROW(),MCOL()
      DEFINE BAR _med_cut OF shortcut PROMPT "Cu<t" ;
         KEY CTRL+X, "Ctrl+X" ;
         PICTRES _med_cut ;
         MESSAGE "Removes the selection and places it onto the Clipboard"
      DEFINE BAR _med_copy OF shortcut PROMPT "<Copy" ;
         KEY CTRL+C, "Ctrl+C" ;
         PICTRES _med_copy ;
         MESSAGE "Copies the selection onto the Clipboard"
      DEFINE BAR _med_paste OF shortcut PROMPT "<Paste" ;
         KEY CTRL+V, "Ctrl+V" ;
         PICTRES _med_paste ;
         MESSAGE "Pastes the contents of the Clipboard"
      DEFINE BAR _med_clear OF shortcut PROMPT "Cle<ar" ;
         PICTRES _med_clear ;
         MESSAGE "Removes the selection and does not place it onto the Clipboard"
      DEFINE BAR 5 OF shortcut PROMPT "-"
      DEFINE BAR _med_slcta OF shortcut PROMPT "Se

I’ll create a subclass of txtTextbox, name it txtVisualCue, and add the following properties:

cCueText = ""
lCueVisible = .F.
cForecolor = ""
lFontItalic = .F.
uOriginalValue = ""
nAlignment = 3
Name = "txtVisualCue"

We’ll store some values from the textbox to the custom properties in the Init event:

PROCEDURE Init
   DODEFAULT()
   WITH THIS
      .lFontItalic = .FontItalic
      .cForeColor = .ForeColor
      .nAlignment = .Alignment
      .uOriginalValue = .Value
      .lCueVisible = EMPTY(This.Value)
   ENDWITH
ENDPROC

The “visual cue” is driven by the lCueVisible property. We’ll assign a value to lCueVisible in the GotFocus and LostFocus events for the textbox:

PROCEDURE GotFocus
   IF This.lCueVisible
      This.lCueVisible = .F.
   ENDIF
ENDPROC
PROCEDURE LostFocus
   IF EMPTY(This.Value)
      This.lCueVisible = .T.
   ENDIF
ENDPROC

Then we’ll use the lCueVisible_Assign method to “drive” the textbox:

PROCEDURE lCueVisible_assign
   LPARAMETERS vNewVal
   THIS.lCueVisible = m.vNewVal

   WITH THIS
      IF .lCueVisible
         .ForeColor = .DisabledForeColor
         .FontItalic = .T.
         .Alignment = 3
         .Value = ALLTRIM(.cCueText)
      ELSE
         .ForeColor = .cForeColor
         .FontItalic = .lFontItalic
         .Alignment = .nAlignment

         IF ALLTRIM(TRANSFORM(.Value)) == ALLTRIM(.cCueText)
            .Value = .uOriginalValue
         ENDIF
      ENDIF
   ENDWITH
ENDPROC

In effect, whenever the Value property is EMPTY(), we’ll display the CueText in the textbox. Anytime the textbox gets focus, we’ll set lCueVisible to .F., which will update the textbox accordingly.

Admittedly, this is a pretty basic example, but this type of textbox has great potential for enhancing the UI of my Visual FoxPro applications.