The Combination List Box

Main Characteristics of Combination List Boxes

Tool Box Icon Appearance on Form

 

A combo box form field behaves like a combination of a list box and an entry field.

Combo boxes are commonly used for presenting a fixed number of choices to the application end-user from which one can be selected, or the end-user can enter a value that is not a member of the list.

They also provide a convenient mechanism for presenting these choices in the form of descriptive text rather than as codes.

Combo boxes have an assignable data type and data length. The default members of the list can be defined as a sequence of strings separated by the semi-colon (;) character. The default value for the combo box can also be defined; if this value matches a member of the list, then that list item appears in the entry field component and is also highlighted in the list. The number of visible lines for a combo box defines the number of list members that are exposed. The total number of members in the list can exceed this number of members. The members of a combo box list can also be established under Zim program control by using the FORM SET LIST command. The available combo box styles are "Manual Drop", "Automatic Drop", "Always Dropped", "Drive List", "Directory List" and "File List".

Combination List Box Attributes

Identification

Attribute Name Default Value Description
Field Type - The type of this form field or of this user interface object. (Read-only).
Field Name variable A string that identifies this form field within the Zim application;
Automatically assigned by the Zim IDE when a new form field is created;
May be changed by the developer, but must always conform to the Zim Object Naming Rules and satisfy the Zim Object Uniqueness Conditions.
Field Number 0 A number that may be used to identify this form field within the Zim application and in Callback Events;
May be changed by the developer and need not be unique;
Value must be an integer between 0 and 999;
Field Tag "" A string that may be used to identify this form field within the Zim application and in Callback Events;
May be changed by the developer and need not be unique;
If left blank, the Zim IDE will assign the value of Field Name to Field Tag.
Directory ZIM The directory that owns the parent form of this form field (Read-only).
Form Name - A string that identifies the parent form of this form field (Read-only).
Help Message "" A help message that will be displayed when this form field or this menu item receives input focus;
Displayed in the status bar of the window associated with the parent form of this form field (if the window object's Status Bar attribute is set to True);
Displayed in a message field if one such field exists in the parent form of this form field.

 

Appearance

Attribute Name Default Value Description
Customized Pointer default The pointer (or cursor) style when the pointer is hovering over (or the cursor is inside) an available form field;
May be selected from the following choices in the list box:
Arrow →  the standard arrow cursor;
Cross-hair →  ;
I-Beam →  ;
Icon →  ;
Resize →  ;
Size NE SW →  ;
Size NS →  ;
Size NW SE →  ;
Size WE →  ;
Up Arrow →  ;
Hourglass →  ;
default →  The pointer style will be I-Beam for Entry Field and Arrow for all other form fields.
Fill Character " " The character used to fill blank spaces in this form field.
Initial Items "" A collection of strings that will be available for selection in this form field.
Each string will appear on a different line;
Strings are terminated by the enter key;
Location - The location (in pixels) of this form field in relation to the top-left corner of its parent form or parent container.
X - The horizontal location of this form field.
Y - The vertical location of this form field.
Reverse Video False True →  The text will appear in white on a black background;
False →  The text will appear in black on a white background;
Size - The size of this form field in pixels.
Width - The width of this form field.
Height - The height of this form field.
Visible True True →  This form field will be visible by default.
Visible Lines 1 The number of visible lines in this entry field, list box or combination list box.

 

Behavior

Attribute Name Default Value Description
Anchoring Top, Left When the window associated with this form field's parent form is resized:
Top →  The top edge of this form field will maintain its distance from the top edge of the window;
Bottom →  The bottom edge of this form field will maintain its distance from the bottom edge of the window;
Left →  The left edge of this form field will maintain its distance from the left edge of the window;
Right →  The right edge of this form field will maintain its distance from the right edge of the window;
None →  The same as Top, Left.
Auto Complete False True →  If the value being entered in this combination list box partially matches a list item, the entered value will be automatically completed with the remaining characters of the matching list item.
Auto Select False True →  The contents or state of this form field will be automatically highlighted when it receives input focus.
Auto Skip False True →  The input focus will automatically skip to the next available form field after the value or state of this form field has been modified.
Docking None Top →  The top edge of the form field will be expanded and placed;
Bottom →  ;
Left →  ;
Right →  ;
Fill →  ;
None →  This form field.

 

Callback Events

Attribute Name Default Value Description
All Callback Events   When any of the following callback event attributes is set to True, this form field will be able to trigger the corresponding callback event;
After the event is triggered, the form input command will be terminated and the following values will populate the Event Vector:
Event.EventType = "FormField";
Event.EventTag = the form field's Field Tag attribute;
Additional values relative to specific callback events (see below);
Note:
Callback events can only be triggered by a form field if it is available and contained in a form that has input focus.
Click False Triggered when the left mouse button is clicked within this form field;
Event.EventName = "Click" added to the Event Vector.
Double Click False Triggered when the left mouse button is double-clicked within this form field;
Event.EventName = "DoubleClick" added to the Event Vector.
Got Focus False Triggered when a mouse click, a tab key press or an accelerator key press causes this form field to acquire the input focus;
Event.EventName = "GotFocus" added to the Event Vector.
Lost Focus
(Always)
False Triggered when a mouse click, a tab key press or an accelerator key press causes this form field to lose the input focus;
Event.EventName = "LostFocus" added to the Event Vector.
Lost Focus
(When Modified)
False Triggered when a mouse click, a tab key press or an accelerator key press causes this form field to lose the input focus after its value has been modified (cf. Modified below);
Event.EventName = "LostFocusModified" added to the Event Vector.
Modified False Triggered when the value or state of this form field is modified by a left mouse button click;
Event.EventName = "Modified" added to Event Vector.
Right Click False Triggered when the right mouse button is clicked on or inside this form field;
Event.EventName = "RightClick" added to the Event Vector.

 

Color

Attribute Name Default Value Description
Background Color variable The background color of the form field, container or user interface object in R(ed) G(reen) B(lue) values;
Foreground Color variable The foreground color of the form field, container or user interface object in R(ed) G(reen) B(lue) values.
Inherit Background Color variable True →  The form field or container will inherit the background color of its parent container or parent form object.
Inherit Foreground Color variable True →  The form field or container will inherit the foreground color of its parent container or parent form object.

 

Properties

Attribute Name Default Value Description
Availability Available The way in which the end-user will interact with this form field:
Available →  This form field can receive input focus and its contents can be modified;
Unavailable →  This form field cannot receive input focus and its contents cannot be modified;
Guarded →  This form field can receive input focus but its contents cannot be modified;
Protected →  This form field cannot receive input focus, its contents cannot be modified and it will appear grayed-out;
Case Mixed The case in which the data contents of this form field will be displayed:
Mixed →  The data will be presented in its original case;
Upper →  The data will be displayed in upper case;
Lower →  The data will be displayed in lower case.
Data Type Alphanumeric The data type of this form field:
Alphanumeric →  May contain letters, digits and punctuation; 
Non-Digit →  May contain all characters except digits;
Numeric →  May contain digits, decimal point, plus and minus signs;
Date →  May contain digits according to the form specified in Input Mask;
Default Data Value "" The default data value of this form field.
Drop Style Always Dropped
Always Dropped →  ;
Manual Drop →  ;
Automatic Drop →  ;
Drive List →  ;
Directory List →  ;
File List →  ;
Length 12 The length of the data displayed in this form field
Justification None The justification applied to the contents of this form field:
Left or None →  the contents will be displayed left-aligned;
Right →  the contents will be displayed right-aligned;
Center →  the contents will be displayed centered.
List Tracks Input False True →  This combination list box
Suppress
Tab Index 0 The relative position of this form field in the tab sequence order for its parent container or form field;
0 →  The relative position of the form field in the structure chart will be used instead.
Tab Stop True True →  This form field will be included in the tab order for its parent container or form;
False →  
Validation
Z-Order >= 10001 The relative depth of this form field in relation to other form fields within the same parent container or form.

 

Style

Attribute Name Default Value Description
Font Microsoft Sans Serif, 8pt The font in which text will be displayed inside this form field.
Name Microsoft Sans Serif The system name of the selected font.
Size 8 The size of the font in units. (Point is the default unit);
Bold False True →  The text inside this form field will appear in bold.
Italic False True →  The text inside this form field will appear in italic.
Strikeout False True →  The text inside this form field will appear with a line across.
Underline False True →  The text inside this form field will appear underlined.
Inherit Font False True →  This form field will inherit all the Font attributes from its parent (form, frame or tab control).

 

Validation

Attribute Name Default Value Description
Accept Abreviations False False →  The data value entered into this form field or the value of the selected list item must always completely match a validation rule;
True →  The data value entered into this form field or the value of the selected list item can partially match a validation rule;
For example: if the validation rule for this field were AAA9999, a data value of AAA1 would be accepted for Val_Accept_Abreviations = True, but rejected for Val_Accept_Abreviations = False.
Blank is NULL False True →  a blank value ("") in this form field will be translated to the Zim null value ($Null).
Error Message "" An error message that will be displayed when the entered or selected value in this form field fails the Validation Rule;
Displayed in the status bar of the window associated with the parent form of this form field (if the window object's Status Bar attribute is set to True);
Displayed in a message field if one such field exists in the parent form of this form field;
Minimum Input Length 0 The minimum number of characters that: must be entered into this form field, or the minimum number of characters in a selected list item for the combo box data value to be valid.
Validation Rule "" The data validation rule that defines a legal value for this form field.
Value Required "" No →  A blank value ("") in this form field is accepted as valid input;
Yes →  A non-blank value must be entered or selected in this form field before is parent form can lose input focus;
Immediate →  a non-blank value must be entered or selected in this form field before the form field itself can lose input focus.