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CLIPBOARD system handle

A handle to the system clipboard widget. The CLIPBOARD handle allows you to implement interactions that allow the user to transfer data between ABL field-level widgets, or between ABL field-level widgets and the widgets of other applications running on the system. ABL can interpret the data read from or written to the system clipboard widget as a single item or as a group of multiple items. These data transfers are typically invoked as cut, copy, and paste operations.

Syntax

CLIPBOARD [ :attribute ] 

attribute
Attributes

Examples

The following code fragment implements cut, copy, and paste operations for the EM_Cut, EM_Copy, and EM_Paste items on the EditMenu menu. It uses the FOCUS handle to reference the widget that has the current input focus.

Note that the fragment tests the widget type of the FOCUS widget in two instances: once when EditMenu is opened during the MENU-DROP event to determine what clipboard operations are valid for the widget, and once again when a clipboard operation is chosen from the menu to determine how the operation is executed for the widget. During the MENU-DROP event, if a particular operation is valid for the FOCUS widget the menu item for that operation is enabled. Otherwise, it is disabled.

During the CHOOSE event for a n enabled menu item, the fragment executes the corresponding clipboard operation in a way that accounts for the unique features of the FOCUS widget. For example, the copy operation (EM_Copy) copies the selected text from an editor widget, copies the label text from a radio set item, and copies a composed true or false message for a toggle box. Your own implementation of these operations for the same widgets can be quite different.

For a complete description of this example, see the chapter on the system clipboard in OpenEdge Development: Programming Interfaces.

DEFINE VARIABLE lStat AS LOGICAL NO-UNDO. 
. . . 
ON MENU-DROP OF MENU EditMenu DO: 
  IF FOCUS:TYPE = "EDITOR" THEN DO: 
    MENU-ITEM EM_Cut:SENSITIVE IN MENU EditMenu = 
      IF LENGTH(FOCUS:SELECTION-TEXT) > 0 THEN TRUE ELSE FALSE. 
    MENU-ITEM Em_Copy:SENSITIVE IN MENU EditMenu = 
      IF LENGTH(FOCUS:SELECTION-TEXT) > 0 THEN TRUE ELSE FALSE. 
    MENU-ITEM EM_Paste:SENSITIVE IN MENU EditMenu = 
      IF CLIPBOARD:NUM-FORMATS > 0 THEN TRUE ELSE FALSE. 
  END. 
  ELSE IF FOCUS:TYPE = "RADIO-SET" OR  
          FOCUS:TYPE = "SELECTION-LIST" OR 
          FOCUS:TYPE = "SLIDER" OR 
          FOCUS:TYPE = "TOGGLE-BOX" THEN DO: 
    MENU-ITEM EM_Cut:SENSITIVE IN MENU EditMenu = FALSE. 
    MENU-ITEM Em_Copy:SENSITIVE IN MENU EditMenu = TRUE. 
    MENU-ITEM Em_Paste:SENSITIVE IN MENU EditMenu = FALSE. 
  END. 
  ELSE IF FOCUS:TYPE = "FILL-IN" THEN DO: 
    MENU-ITEM EM_Cut:SENSITIVE IN MENU EditMenu = 
      IF LENGTH(FOCUS:SCREEN-VALUE) > 0 THEN TRUE ELSE FALSE. 
    MENU-ITEM Em_Copy:SENSITIVE IN MENU EditMenu = 
      IF LENGTH(FOCUS:SCREEN-VALUE) > 0 THEN TRUE ELSE FALSE. 
    MENU-ITEM EM_Paste:SENSITIVE IN MENU EDitMenu = 
      IF CLIPBOARD:NUM-FORMATS > 0 THEN TRUE ELSE FALSE. 
  END. 
  ELSE DO: 
    MENU-ITEM EM_Cut:SENSITIVE IN MENU EditMenu = FALSE. 
    MENU-ITEM EM_Copy:SENSITIVE IN MENU EditMenu = FALSE. 
    MENU-ITEM EM_Paste:SENSITIVE IN MENU EditMenu = FALSE. 
  END. 
END. /* ON MENU-DROP IN EditMenu */ 
ON CHOOSE OF MENU-ITEM EM_Cut IN MENU EditMenu DO: 
  IF FOCUS:TYPE = "EDITOR" THEN DO: 
    IF FOCUS:SELECTION-START <> FOCUS:SELECTION-END THEN ASSIGN 
      CLIPBOARD:VALUE = FOCUS:SELECTION-TEXT 
      lStat           = FOCUS:REPLACE-SELECTION-TEXT(""). 
    ELSE ASSIGN 
      CLIPBOARD:VALUE    = FOCUS:SCREEN-VALUE 
      FOCUS:SCREEN-VALUE = "". 
  END. 
  ELSE ASSIGN /* For FILL-IN */ 
    CLIPBOARD:VALUE    = FOCUS:SCREEN-VALUE 
    FOCUS:SCREEN-VALUE = "". 
END. /* ON CHOOSE OF MENU-ITEM EM_Cut */ 
ON CHOOSE OF MENU-ITEM EM_Copy IN MENU EditMenu DO: 
  IF FOCUS:TYPE = "EDITOR" THEN 
    IF FOCUS:SELECTION-START <> FOCUS:SELECTION-END THEN 
      CLIPBOARD:VALUE = FOCUS:SELECTION-TEXT. 
    ELSE  
      CLIPBOARD:VALUE = FOCUS:SCREEN-VALUE. 
    ELSE IF FOCUS:TYPE = "RADIO-SET" THEN 
      CLIPBOARD:VALUE = ENTRY(LOOKUP(FOCUS:SCREEN-VALUE,  
        FOCUS:RADIO-BUTTONS) - 1, FOCUS:RADIO-BUTTONS). 
    ELSE IF FOCUS:TYPE = "TOGGLE-BOX" THEN 
      IF FOCUS:SCREEN-VALUE = "yes" THEN 
        CLIPBOARD:VALUE = FOCUS:LABEL + " selected.". 
      ELSE 
        CLIPBOARD:VALUE = FOCUS:LABEL + " not selected.". 
    ELSE /* For FILL-IN */  
      CLIPBOARD:VALUE = FOCUS:SCREEN-VALUE. 
END. /* ON CHOOSE OF MENU-ITEM EM_Copy */ 
ON CHOOSE OF MENU-ITEM EM_Paste IN MENU EditMenu DO: 
  IF FOCUS:TYPE = "EDITOR" THEN DO: 
    IF FOCUS:SELECTION-START <> FOCUS:SELECTION-END THEN 
      lStat = FOCUS:REPLACE-SELECTION-TEXT(CLIPBOARD:VALUE). 
    ELSE  
      aResult = FOCUS:INSERT-STRING(CLIPBOARD:VALUE). 
  END. 
  ELSE /* For FILL-IN */ 
    FOCUS:SCREEN-VALUE = CLIPBOARD:VALUE. 
END. /* ON CHOOSE OF MENU-ITEM EM_Paste */ 
. . . 

The following r-clpmul.p procedure demonstrates interaction with the clipboard using multiple items. The procedure copies out four rows of five numbers to the clipboard. It first displays the clipboard data as a single item, and then as a list of multiple items.

As a further demonstration of how the CLIPBOARD handle works with multiple items, try the following experiment:

  1. Run the procedure, and at the pause, paste the result into an edit tool in your window system, such as Notepad in Windows.
  2. You may have to select and copy text in the edit tool to activate the system clipboard before running the procedure.
  3. Modify the text in the edit tool, leaving at least one tab or newline character, and copy it back to the clipboard from the edit tool.
  4. Respond to the pause in the procedure to see how the modified clipboard data is displayed.
  5. r-clpmul.p
    DEFINE VARIABLE ClipBuffer AS CHARACTER NO-UNDO 
      VIEW-AS EDITOR SIZE 60 BY 5. 
    DEFINE VARIABLE ClipItem   AS CHARACTER NO-UNDO. 
    DEFINE VARIABLE ix         AS INTEGER   NO-UNDO. 
    /* Copy rows of integer items to the clipboard, display the clipboard value. */ 
    ASSIGN 
      CLIPBOARD:MULTIPLE      = TRUE 
      CLIPBOARD:ITEMS-PER-ROW = 5. 
    REPEAT ix = 1 TO 20:  
      CLIPBOARD:VALUE = STRING(ix). 
    END. 
    ASSIGN 
      CLIPBOARD:MULTIPLE = FALSE 
      ClipBuffer         = CLIPBOARD:VALUE. 
    ENABLE ClipBuffer WITH FRAME A. 
    DISPLAY SPACE(1) ClipBuffer LABEL "Clipboard Data" WITH FRAME A. 
    PAUSE. 
    /* Display each item of the clipboard value. */ 
    ASSIGN 
      CLIPBOARD:MULTIPLE = TRUE 
      ClipItem           = "". 
    REPEAT WHILE ClipItem <> ?: 
      ClipItem = CLIPBOARD:VALUE. 
      IF ClipItem <> ? THEN 
        DISPLAY SPACE(1) ClipItem FORMAT "x(16)" LABEL "Clipboard Item"  
          WITH DOWN FRAME B. 
    END. 
    CLIPBOARD:MULTIPLE = FALSE. 
    

Notes
See also

FOCUS system handle


OpenEdge Release 10.2B
Copyright © 2009 Progress Software Corporation
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