Controlling Form Behavior and Format Using Properties, Property Classes, and the Property Palette

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Chapter 5 Controlling Form Behavior and Format
Using Properties, Property Classes, and the
Property Palette
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• In this chapter you will
• Learn the purpose of properties and property
  types
• Learn to operate the Property Palette
• Create and use property classes
• Create and use visual attributes
• Control form navigation using properties
• Learn about important block properties
• Create reusable components using object groups
  and libraries
• Create and use SmartClasses
• Change properties during runtime

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Properties and Property Types

• A property is a setting in a program.
• A typical program can have hundreds of settings
  that control application characteristics such as
  font, width of a text item, or boilerplate.

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Properties and Property Types

• A form is also a program and has hundreds of
  property settings.
• The Data Block Wizard, Layout Editor Wizard, and
  the Layout Editor can be used to set properties.
• The former tools cannot set all form properties.
  However the Property Palette can.
• The Property Palette is a dialog box that
  displays the properties for the currently
  selected item.
• Settings are added to properties on the Property
  Palette using drop-down lists, text items,
  editor, and color palettes.

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Properties and Property Types
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Properties and Property Types
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Properties and Property Types
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Properties and Property Types
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Properties and Property Types

• It is possible to select multiple objects and
  open a Property Palette that displays the
  property values for all of the items.
• A value of asterisks () indicate the
  selected objects property values differ.
• An actual value indicates the selected objects
  property values are the same.

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Properties and Property Types

• When multiple item properties are displayed in a
  Property Palette, two views are available
• The Intersection view displays properties that
  exist on each of the selected items.
• The Union view displays all properties whether
  they exist on all selected objects or not.
• The Intersection/Union tool located at the top of
  the Property Palette can be used to toggle the
  two views.

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Properties and Property Types
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Properties and Property Types

• Normally the Property Palette only shows
  properties for the currently selected object(s).
  
• The properties in the Property Palette change
  when a new object is selected.
• It is possible to keep a Property Palette open
  with existing properties and open a second
  Property Palette for a new object.
• The Pin/Unpin tool located on the Property
  Palette causes a palette to stay open or to
  close.

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Properties and Property Types
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Properties and Property Types

• It can be difficult to locate a property on the
  Property Palette.
• The Find tool is used to locate the desired
  property.

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Properties and Property Types
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Creating and Using Property Classes

• A property class is a form object that contains a
  set of developer defined properties.
• Property classes are assigned to other objects
  superceding their existing properties.
• Property classes are assigned to other objects
  using the Subclass Information property.
• Property classes are excellent productivity and
  standardization tools.

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Creating and Using Property Classes

• Property classes can be created on the Object
  Navigator using the Create tool.
• Property class properties can be viewed by
  opening a Property Palette for the property
  class.
• Properties can be added using the Add Property
  tool located on the Property Palette.
• The Add Property tool opens a dialog box that
  displays all properties available for the
  property class.

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Creating and Using Property Classes
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Creating and Using Property Classes

• The Delete Property tool is used to delete
  properties from the property class.
• You can determine that an object is using a
  property class on the Object Navigator by the red
  arrow and cross symbol that appear below the
  objects icon.
• You can determine a property whose value is
  supplied by a property class. A carriage return
  symbol will precede the property on the Property
  Palette.

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Creating and Using Property Classes
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Creating and Using Visual Attributes

• Visual attributes are a form object similar to a
  property class.
• Visual attributes only contain font and color
  properties.
• Visual attributes are used to format data block
  items, canvases, windows, alerts, and LOVs.

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Creating and Using Visual Attributes

• There are three types of visual attributes
• Common - Used to format most items
• Title - Used to format the frame title
• Prompt - Used to format data block item prompts
• Visual attributes are created on the Object
  Navigator using the Create tool.
• Visual attribute properties are modified using
  the Property Palette.

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Creating and Using Visual Attributes
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Creating and Using Visual Attributes

• Visual attributes are assigned to the object
  using one of the following properties
• Current Record Visual Attribute Group (data
  block, data block item)
• Visual Attribute Group
• Prompt Visual Attribute Group
• Frame Title Visual Attribute Group

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Creating and Using Visual Attributes

• The Current Record Visual Attribute Group
  properties on the data block and data block item
  objects use the visual attributes to format the
  currently selected record.
• Current Record Visual Attribute Group properties
  are excellent tools to identify the current
  record when the form contains multiple tabular
  data blocks.

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Controlling Form Navigation Using Properties

• By default, block and data block item navigation
  is determined by the order the objects are
  displayed in the Object Navigator.
• The form, data block, and data block item objects
  have properties that override and further control
  the default navigation.

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Controlling Form Navigation Using Properties
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Controlling Form Navigation Using Properties

• Data blocks have a Navigation Style property that
  determines where the input focus navigates to
  when the operator tabs from the last item in a
  record.
• Settings are
• Same Record
• Change Record
• Change Data Block
• Data blocks also have a Previous Navigation Data
  Block and Next Navigation Data Block property
  that override the default navigation on the
  Object Navigator.

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Controlling Form Navigation Using Properties

• Data block items have a Previous Navigation Item
  and Next Navigation Item property that override
  the default navigation set on the Object
  Navigator.
• Data block items have a Keyboard Navigable
  property that prevents the operator from tabbing
  into an item.
• Data block items also have a Query Allowed
  property that prevents the operator from tabbing
  into a data block item when the data block is in
  the Query mode.

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Controlling Form Navigation Using Properties

• Form objects have a Mouse Navigable property that
  determines which object can receive the input
  focus using the mouse. Settings include
• Form
• Data block
• Record
• Item
• Form is the default setting.

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Important Data Block Properties

• Data blocks have several important properties.
• Number of Records Displayed controls the amount
  of records visible to the operator at a given
  time.
• The WHERE clause property allows the developer to
  limit the records displayed on the data block.
• The Database Block property determines whether
  the data block is a control block.
• The Query Allowed, Insert Allowed, Update
  Allowed, and Delete Allowed properties can
  suppress SQL statements issued by the data block.

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Creating Reusable Components Using Object Groups
and Libraries

• Standard reusable form components can increase
  developer productivity.
• Forms Builder has two objects that can be used to
  standardize form components
• Object Group
• Object Library

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Creating Reusable Components Using Object Groups
and Libraries

• An object group is a form component that contains
  a set of form components.
• When an object group is copied into another form
  its components are moved to the appropriate
  object in the form.
• Object groups eliminate the labor of copying many
  objects into a form.

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Creating Reusable Components Using Object Groups
and Libraries
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Creating Reusable Components Using Object Groups
and Libraries

• A good use of an object group is to have default
  components such as the content canvas, visual
  attributes, property classes, windows, and
  triggers. The object group can be used to set up
  the form and get a quick start.
• Object groups are created on the Object Navigator
  using the Create tool.
• Objects are added to the group by dragging them
  from the form into the object group.

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Creating Reusable Components Using Object Groups
and Libraries

• An object library is an external module that can
  contain any form component.
• Since the objects are stored outside a form there
  is a smaller chance that the standard object was
  modified by a developer.
• Object libraries are created on the Object
  Navigator.
• Double-clicking the object library opens the
  Object Library dialog box.

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Creating Reusable Components Using Object Groups
and Libraries

• Objects are moved into the object library by
  dragging them from the form into the dialog box.
• Objects are moved into the form by dragging them
  from the dialog box into the form.
• Object libraries have tabs which are used to
  group common objects.

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Creating Reusable Components Using Object Groups
and Libraries

• Object libraries have a file extension of .olb.
• Stndrd20.olb is an Oracle Form Builder 6i demo
  object library.
• Ofgstnd1.olb is an Oracle Forms Builder 9i demo
  object library.
• Object libraries are created on the Object
  Navigator using the Create tool.

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Creating Reusable Components Using Object Groups
and Libraries
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Creating Reusable Components Using Object Groups
and Libraries

• Existing object libraries can be brought into the
  IDE using the File/Open menu selection.
• Once an object library has been loaded into the
  IDE it will automatically reload each time Forms
  Builder is opened.
• Object libraries can be removed from the IDE by
  selecting the library and pressing the Delete key.

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Creating and Using SmartClasses

• Selecting an object node and pressing the right
  mouse opens a popup menu.
• One of the options on the popup menu is
  SmartClasses.
• SmartClasses is a submenu that displays objects
  that can be copied into the object class.
• The set of SmartClasses objects change dependant
  upon the object class selected.

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Creating and Using SmartClasses
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Creating and Using SmartClasses

• Oracle has developed a set of objects that will
  appear in the SmartClasses menu.
• You can add your own objects by designating an
  object in an object library as a member of the
  SmartClasses.
• The Edit/SmartClass menu option is used to
  designate an object library object a member of
  the SmartClasses.

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Creating and Using SmartClasses
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Changing Properties at Runtime

• Properties are normally set using the Property
  Palette or other Forms Builder tools.
• Properties can also be set at runtime using a
  built-in subprogram.
• A built-in subprogram is an Oracle developed
  procedure or function that performs a specific
  task.
• Every object has a built-in subprogram that can
  be used in a PL/SQL script to modify the objects
  properties.

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Changing Properties at Runtime

• The built-ins do not modify all of the items
  properties. Visual properties such as text item
  height and width are not modifiable.
• It is very common to modify data block and data
  block item properties.
• The Set_block_property, Set_block_item_property,
  and Set_block_item_instance_property are commonly
  used built-ins that are representative of the
  built-in class.
• The built-ins are procedures and have argument
  lists.

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Changing Properties at Runtime
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Changing Properties at Runtime

• The Set_block_item_property and
  Set_block_item_instance properties are similar
  but have a small difference.
• The Set_block_item_property built-in modifies the
  property for every occurrence of the item in the
  data block.
• The Set_block_item_instance_property built-in
  modifies the property for select records only.
  You must identify the row when using this
  built-in.

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Where You Are and Where Youre Going

• You have seen
• That a major part of developing a form is setting
  properties on the Property Palette
• The functionality of a number of different
  properties that affect the data block, data block
  item, and form
• How to create visual attributes, property
  classes, object groups, and object libraries
• How to set properties during runtime

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Where You Are and Where Youre Going

• In the next chapter you will see
• How to use the PL/SQL editor, the fourth
  development tool
• How to create triggers that execute PL/SQL
  statements
• How to add you own logic to the form using these
  tools