Front End Development – 4GL APPLICATION FRAMEWORK

OLE Container Support

Zim supports the creation and manipulation of ActiveX objects and containers. An OLE or ActiveX container is used to embed the COM object into an application. Examples of a container are Visual Basic and Microsoft Word, in addition to Zim itself.

OLE Container Datatype

The OLE or ActiveX Container is a formfield where ft (“fieldtype”) is set to “E”.
An OLE Container can either be borderless or have an OLE Object border. The OLE Object border is a dashed line for embedded objects and a solid line for linked objects. A selection border surrounds OLE Containers when they have focus. They respond to mouse clicks and transmit keys as image widgets do.
OLE Containers can be assigned OLE object filenames or unique class identifiers. These names or identifiers can be placed in the default value of the created object or can be assigned at runtime. Zim checks the file or class identifier for the OLE Container for Zim’s path characters then checks if it is a valid class. If it is not, then Zim assumes it is a filename.

Painter Support for OLE Containers

The Zim Screen Painter provides an OLE Container widget on its menu and gallery. The support in Screen Painter for the OLE Container widget is almost identical to its support for image widgets. The developer does not need to specify an OLE source filename for the OLE Container widget since the OLE container can be empty. If an OLE source filename has been associated with the OLE Container but the file does not exist, the contents of the OLE container widget appear as the OLE source filename centered within hatches; otherwise the OLE object is displayed within the OLE Container.

Support for Linked Objects and Limited Support for Embedded Objects

The Screen Painter creates linked OLE Containers by setting the WdgSubClass of the formfield to 1 when it is first added. Embedded objects have WdgSubClass set to 0. Zim does not support visual editing (also known as in-place activation) of embedded objects and does not store embedded objects as blobs in its data files. The support for embedded objects is limited to enabling assignment, cut, and paste of embedded objects. Linked OLE Containers are stored in Zim’s data files as monikers: filenames with extra information. A moniker of the linked formfield is kept up to date, in case a new object was pasted into the container. OLE Container Widgets that contain embedded objects return $null when they are queried. Activation of OLE Containers occurs in the server application.

FORM SET Command

The OLE objects in the OLE Containers can be manipulated programmatically using the following command:

FORM SET (VERB verbName) | fieldname | formname | (formnum, fieldnum, subscript)|

where verbName is a string or an expression that evaluates to a string
fieldname is the name of an OLE Container formfield on the form
formname is the name of a form
formnum is the number of the form
fieldnum is the number of a field
subscript is the subscript of a formfield
The following verbNames are supported and available as constants:

Verbname
Primary
Cut
Copy
Paste Link
Paste
Paste Special

Positive numbers are specific to the object.
You can use the registry information of an OLE object to determine its primary and other supported verbs. This information can also be obtained using the Zim $GetProperty command.

Cut, Copy and Paste, Paste Link, and Paste Special Menu Items

The cut, copy, paste, Paste Link, and Paste Special menu items are grayed appropriately when the OLE Container formfield has the focus. Linked items can paste only links; embedded objects can paste both embedded objects and links. Paste Link and Paste Special are available only for OLE Container formfields.

$GetProperty (‘OleVerbList’, FileOrClassName)

The $GetProperty command returns the list of supported verbnames of a file or OLE class. Semicolons separate the verbs in the returned list.

Default Double-click Action on OLE Container Widgets.

Unguarded OLE containers invoke the OLE objects primary verb when double-clicked if DoubleClick has not been identified as a transmit event.

Default Right-click Action on OLE Container Widgets.

Unguarded OLE containers display their available OLE verbs in a right-click menu when they are right-clicked if RightClick has not been identified as a transmit event. If an action is chosen from the right-click menu, it is performed.

WINDOW STATUS

Captures and updates the status of an open window.

Syntax

WINDOW STATUS [window]

Parameters

window

where window can be:
name: The name of an open window. The software looks up name in the currently accessed directories in the usual way. A compiled command using name contains the unambiguous name of the window (including a reference to an application directory) that was found at compile time.

(expr): A character string, or an expression that evaluates to a character string, that is to be used at run time as a window object name. The parentheses must be entered. A compiled command using (expr) can refer to many windows, at the risk of encountering an ambiguous window name (i.e., no directory specified when versions of the window are available in two or more directories).
If neither name nor (expr) is specified, the current window is assumed.

Comments

WINDOW STATUS gets the current status of an open window and updates the structure ThisWindow. This is particularly useful when the end user moves and/or resizes a window without program control.

Example

window open wContracts

form display input

…

window status

list ThisWindow

After an event has been generated by the FORM INPUT, the size and position (among other information) can be retrieved by the means of the WINDOW STATUS for later usage with the structure ThisWindow.

See Also

WINDOW SET

Syntax

WINDOW SET (<option>) [window]

Modifies the individual attributes of opened windows.

Example

WINDOW OPEN <name>
WINDOW SET (label "Whatever Title you want to use")

Parameters

option

Options that affect certain window attributes. Can be
[UN]AVAILABLE
BORDER color
[NOT] CLOSED
FILLCOLOR color
FONT expr
[NOT] FUNCTIONKEYS
[NOT] GOTFOCUS
LABEL expr
MOUSEPOINTER fileName
[NOT] LOSTFOCUS
[NOT] MESSAGES
[NOT] MODAL
PENCOLOR color
POINTSIZE expr
STATUSBARTEXT statusBarText
TABORDER BY setting

window

Window can be
name
The name of the window that you want to open. The software looks up name in the currently accessed directories in the usual way. A compiled WINDOW OPEN command using name contains the unambiguous name of the window (including a reference to an application directory) that was found at compile time.
(expr )
A character string, or an expression that evaluates to a character string, that is to be used at run time as the name of the window. The parentheses must be entered.
If neither name nor expr is specified, the current window is assumed.

Option	Description
[UN]AVAILABLE	Indicates if the application user can initiate a focus shift to the window.
BORDER color	Sets the border color.
[NOT] CLOSED	Indicates if the specified event causes a callback.
FILLCOLOR color	Sets the background color.
FONT expr	Sets the font.
FUNCTIONKEYS ON \| OFF	Controls pre-defined accelerator keys.
[NOT] GOTFOCUS	Indicates if the specified event causes a callback.
LABEL expr	Establishes the window’s label.
[NOT] LOSTFOCUS	Indicates if the specified event causes a callback.
MESSAGES ON \| OFF	Controls the display of help and error messages.
[NOT] MODAL	Controls if the window is a modal window.
PENCOLOR color	Sets the foreground color.
POINTSIZE expr	Sets the point size of the font.
TABORDER BY setting	Specifies how focus moves in the window. Can be TABINDEX (based on the form field’s sequence number), FIELDNUM (based on field identification number), ROWCOL (left to right), or COLROW (top to bottom).

Comments

The attributes changed are only applicable to an opened window. After the window is closed, all attributes set are lost. Opening subsequent windows will not inherit attributes set to previous windows.

If there is no opened window, the attribute settings are ignored.

The WINDOW SET command changes certain window attributes whose default states are defined in the Object Dictionary.

See Also

The Status Bar

FORM OPEN

Opens a form or display in the current window.

Syntax

FORM OPEN [object][ NOCLEAR][ NOGUIUSE]

Parameters

object

name: The name of the form or display to be opened.

(expr): A character string, or an expression that evaluates to a character string, to be used at run time as the name of the form or display.
Using (expr) enables one FORM OPEN command to specify different forms or displays, at the risk of encountering an ambiguous name.

FORM OPEN (expr) cannot be used to open forms defined in a foreign directory.

NOCLEAR The values currently assigned to the constituent form fields are to be retained.
If omitted, each form field value is reset to its default.

NOGUIUSE The current form or display is opened for internal use only and is never displayed.
It is intended for the performance improvement whenever forms are used as arrays in memory.
Any attempt to display these objects will be ignored.
Other operations are accepted as usual.

Comments

The FORM OPEN command initializes a form or display for use.
The form or display is displayed using the FORM DISPLAY command, and input is requested using the FORM INPUT command.

The form or display specified in a FORM OPEN command remains the current form in its window until a FORM OPEN, FORM CLOSE, or WINDOW CLOSE command is executed.
Each window has its own current form.

When a FORM OPEN command is executed, all ,em>form field attributes are reset to their defined values.
An exception is the field’s value, which is not reset if the NOCLEAR option is used.

The FORM OPEN command also establishes a form for use as an in-memory EntitySet.
When treated as an EntitySet, a standalone form has only one record.
The forms in a display have as many records as there are instances of a particular form in the display.

Examples

form open dAddEmps

Opens a display and resets all constituent form fields to their default values.

form open fAddEmps form display input form close : form open fAddDepts form display close : form open fAddEmps noclear form display

Opens a form and resets its field values, then displays the form and requests user input. Next, a second form is opened and displayed.
Finally, the first form is opened again, and the field values input earlier are re-displayed (because the NOCLEAR option was specified).

form open ($ concat(" fContracts", ContractType))

Opens a certain form dynamically by type.

See Also

FORM CLEAR

FORM CLOSE

FORM SET

FORM DISPLAY

Displays some or all of the form fields of the currently open form or display in the current window.

Syntax

FORM DISPLAY [ option ] [ object ]

Parameters

option

Can be
BELL
Sounds the terminal bell when the FORM DISPLAY command is executed. On older machines, the PC bell is rung. Newer machines must be equipped with a sound card and speakers in order for you to hear the bell.
INPUT
Shifts focus to the form and puts the application user in control of the interface after the FORM DISPLAY command is executed.
NOCLEAR
Prevents the contents of the window from being cleared before the FORM DISPLAY is carried out. Otherwise, the current window is cleared automatically.
NOLABEL
Prevents the contents of the current window from being cleared, and displays all specified fields that contain a visible value.
NOVAR
Prevents the contents of the current window from being cleared, and displays all specified fields that have no visible value.
PURGE
Specifies unprocessed input received before the form was displayed is to be ignored. Eliminates the possible effects of inadvertent keystrokes or mouse actions.

object

Can be
form
The name of the currently open form or display. Specify a particular instance of a form in brackets beside the object’s name.
formfield
The name of a particular form field within the currently open form or display. Specify a particular instance of a form field in brackets beside the form field’s name.
([exp1 ],[exp2 ],[exp3 ])
Positive integers or expressions that evaluate to positive integers, that identify a particular form or form field. Exp1 identifies the form number; exp2, the field number; exp3, the instance of the form or form field in the display. At a minimum, either exp1 or exp2 must be specified.

Comments

The current window must be activated (WINDOW ACTIVATE) for the displayed objects to be visible.
FORM DISPLAY displays form fields with values as they exist at the time the command is executed. If the application program changes the value of a field, the field must be re-displayed if the application user is to see the change.
A masked field that has no data value is displayed without the mask if the field is unavailable to the application user (i.e., protected or guarded). The mask of such a field is shown or suppressed when its availability changes (as a result of the FORM SET command).

Example

form display fGrandTot fInvItem.InvItemTot

Redisplays all fields of one form, and one field of another form.

form display input bell (2,,5)

Sounds the bell while re-displaying all form fields in the fifth instance of form number 2.
Name of the application directory in which the specified object can exist. If the dirname is omitted, the object can be created in any number of directories.

FORM SET LIST

Setting Contents of List Boxes and Combo Boxes

Introduction

In this module, we will explore how to set the contents of list boxes and combo boxes in forms. This is a fundamental skill for creating dynamic and interactive web forms. We will cover two methods: using an expression and using a set.

Method 1: Using an Expression

Command: FORM SET LIST formfield LIST expression

Parameters:

formfield: The target list box or combo box in your form.
expression: A character string or an expression that evaluates to a character string. Items in the expression must be separated by semicolons.

Example:

form set list fCDLFind.FieldName \
list " ProdCode ; ProdDesc ; UnitPrice ; QOH ; MinQty"

In this example, the combo box fCDLFind.FieldName is populated with field names specified in the string.

Method 2: Using a Set

Command: FORM SET LIST formfield FROM [ num ] [ setspec ] [FORMAT expression]

Parameters:

formfield: The target list box or combo box in your form.
num: The number of items to set in the list box or combo box. This can be an integer, a variable, or the word ALL.
setspec: A set specification whose members are used to set the contents of the list box or combo box. If omitted, the current set is used.
expression: An expression to format each item. This can be omitted if setspec is an unstructured application document.

Example:

form set list fCustomer.StateTab from states sorted by StCode \
format $ concat(StCode, " ", StDesc)

In this example, the list box fCustomer.StateTab is populated with state codes followed by state names, sorted by StCode.

Key Points to Remember

When using an expression, ensure items are separated by semicolons.
When using a set, you can specify the number of items and format each item using an expression.
Data populated from a set is left-justified regardless of data type.

Practice Exercise

Try setting the contents of a list box in your form using both methods. Experiment with different expressions and sets to see how the contents change.

See Also

WINDOW ACTIVATE

Makes an open window available for viewing and interaction by the application user.

Syntax

WINDOW ACTIVATE [window] [EXPOSE|HIDE]

Parameters

window	Window can be name The name of an open window. The software looks up name in the currently accessed directories in the usual way. A compiled command using name contains the unambiguous name of the window (including a reference to an application directory) that was found at compile time. (expr ) A character string, or an expression that evaluates to a character string, that is to be used at run time as a window object name. The parentheses must be entered. A compiled command using (expr) can refer to many windows, at the risk of encountering an ambiguous window name (i.e., no directory specified when versions of the window are available in two or more directories). If neither name nor (expr) is specified, the current window is assumed.
EXPOSE	(DEFAULT) Specifies that the window is to be displayed over any other active windows already on the screen.
HIDE	Specifies that the window is to be displayed beneath any other active windows already on the screen.

Comments

WINDOW ACTIVATE makes an open window visible on the terminal screen so that the application user can interact with the window. Note, however, that an input request relating to an inactive window (from a FORM INPUT, INPUT, or MENU INPUT command) automatically activates that window.

WINDOW ACTIVATE does not make the specified window the current window. If the specified window is already the current window, it remains the current window.

Separating the opening of a window (WINDOW OPEN) from the presentation of a window to the application user (WINDOW ACTIVATE) enables you to prepare the window and its contents before making the window visible. Similarly, you can keep a window open for long periods of time, activating it only when needed.

Example

window open wContracts

menu open mContracts

menu display

form open fContracts

form display

window activate

Opens a window, and then opens and displays a menu and form in the window. Once the window is initialized, the WINDOW ACTIVATE command presents it to the application user.

window open wTrace

…other commands…

window activate wTrace

…other commands…

window deactivate wTrace

Activates a trace window when it is required.

See Also

WINDOW MOVE

Moves a window to a new location on the screen.

Syntax

WINDOW MOVE [window] TO position [EXPOSE|HIDE]

Parameters

window	Window can be name The name of an open window. The software looks up name in the currently accessed directories in the usual way. A compiled command using name contains the unambiguous name of the window (including a reference to an application directory) that was found at compile time. (expr ) A character string, or an expression that evaluates to a character string, that is to be used at run time as a window object name. The parentheses must be entered. A compiled command using (expr) can refer to many windows, at the risk of encountering an ambiguous window name (i.e., no directory specified when versions of the window are available in two or more directories). If neither name nor (expr) is specified, the current window is assumed.
position	Position specifies the new location of the upper edge and left-hand edge of the window, and also changes the values for the system variables ThisWindow.WindowRow and ThisWindow.WindowCol. A window’s position is always relative to its physical parent. The physical parent of a clipped window is another window (parentwin). The physical parent of a pop-up window is the terminal. If position is such that the window moves out of bounds, it is automatically adjusted so that the window remains entirely within the parent’s boundaries.
EXPOSE	(DEFAULT) Specifies that the window is to be displayed over any other active windows already on the screen.
HIDE	Specifies that the window is to be displayed beneath any other active windows already on the screen.

Comments

The WINDOW MOVE command enables an application program to establish a new location for an open window.

If the specified window is active, it is displayed in its new position. If the window is open but not active, the WINDOW MOVE command establishes the position at which the window is to appear when activated.

Example

To move the window wStateCodes to a specified location, enter the following command:

window move wStateCodes to 200 400

See Also

DISPLAY DEFINE

Invokes Zim IDE to edit a display.

Syntax

DISPLAY DEFINE displayname [[IN] dirname]

Parameters

displayname

The name of a new or existing display.

dirname

The name of the application directory in which the specified display can exist. If the display does not exist in the provided application directory, it will be created there.

If omitted:

the display will be selected from the first application directory in which it exists.

if the display does not exist, it will be created in the ZIM application directory.

Examples

Invokes Zim IDE to edit the display dAppEmps:

display define dAppEmps

If dAppEmps does not exist in any application directory, it will be created in the ZIM application directory.

Otherwise, it will be selected from the first application directory in which it exists.

display define dAppEmps ZIM

If dAppEmps does not exist in the ZIM application directory, it will be created there.

It will be selected from the ZIM application directory only if it exists there.

display define dAppEmps EMPS

If dAppEmps does not exist in the EMPS application directory, it will be created there.

It will be selected from the EMPS application directory only if it exists there.

Syntax

WINDOW DEFINE winname [[IN] dirname]

Parameters

winname

The name of a new or existing window.

dirname

The name of the application directory in which the specified window can exist. If the window does not exist in the provided application directory, it will be created there.

If omitted:

the window will be selected from the first application directory in which it exists.

if the window does not exist, it will be created in the ZIM application directory.

Examples

Invokes Zim IDE to edit the window wAddEmps:

window define wAddEmps

If wAddEmps does not exist in any application directory, it will be created in the ZIM application directory.

Otherwise, it will be selected from the first application directory in which it exists.

window define wAddEmps ZIM

If wAddEmps does not exist in the ZIM application directory, it will be created there.

It will be selected from the ZIM application directory only if it exists there.

window define wAddEmps EMPS

If wAddEmps does not exist in the EMPS application directory, it will be created there.

It will be selected from the EMPS application directory only if it exists there.

OLE Container Datatype

Painter Support for OLE Containers

Support for Linked Objects and Limited Support for Embedded Objects

FORM SET Command

Cut, Copy and Paste, Paste Link, and Paste Special Menu Items

$GetProperty (‘OleVerbList’, FileOrClassName)

Default Double-click Action on OLE Container Widgets.

Default Right-click Action on OLE Container Widgets.

Syntax

Parameters

Comments

Example

Syntax

Example

Parameters

Comments

Syntax

Parameters

Comments

Examples

Syntax

Parameters

Comments

Example

See Also

Setting Contents of List Boxes and Combo Boxes

Introduction

Method 1: Using an Expression

Method 2: Using a Set

Key Points to Remember

Practice Exercise

Syntax

Parameters

Comments

Example

Syntax

Parameters

Comments

Example

Syntax

Parameters

Examples

Related topics

Syntax

Parameters

Examples

Related topics