Workbench User Guide : 6. Creating and Using Basic Fields : Common Field Properties : Field Biases
 
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Field Biases
Each frame can operate in one of several modes. OpenROAD Workbench provides six frame modes: Update, Read, Query, and three user modes (User1, User2, User3) that you can use as you see fit. As a frame runs, you change its current mode by changing the CurMode attribute.
Every field has a bias for each of the six modes. The bias attributes of a field are as follows:
• UpdateBias
• ReadBias
• QueryBias
• User1Bias
• User2Bias
• User3Bias
Another bias attribute, AllBias, lets you set a single bias value for all six modes.
A field's current bias is the bias setting for a frame's current mode. The bias setting for a mode determines how the user interacts with the field when the frame is in that mode. A field's bias can be used, for example, to control whether a user can enter data in a field, whether the field is dimmed, and even whether the field is visible.
The current bias of a field may also determine what events are generated in connection with the field. For example, a DragSegment event is generated for a field only when the field has the DragSegment bias; no event is generated for a field when its bias is Dimmed.
When you create a field using the Frame Editor, a default initial bias is set for each frame mode. You can change a field's initial bias by using the Property Inspector or by using the Bias menu commands.
The following section describes the OpenROAD field biases. The biases are organized by the following categories:
• Interactive Biases)
• Passive Biases)
• Select Biases)
• Draw Biases)
Interactive Biases
FB_CHANGEABLE
Specifies that end users can select or tab to the field and, if appropriate, edit its contents
FB_LANDABLE
Specifies that end users can select or tab to the field, but cannot change its data
Passive Biases
FB_VISIBLE
Specifies that the field is displayed, but the end user cannot interact with it
Note:  This bias does not even allow, for example, the end user to scroll multiline entry fields to view their entire contents. For such limited interaction, see the FB_VIEWABLE property.
FB_DIMMED
Specifies that the field is dimmed and end users cannot interact with it. (For systems that do not support the dimmed setting, selecting this bias makes the field visible.)
FB_INVISIBLE
Specifies that the field is not displayed on the form. Although end users cannot interact with the field, you can access it in your 4GL code.
FB_VIEWABLE
Specifies that the field is displayed on the form and end users may use the mouse only to scroll through its contents. (Because the field cannot accept input focus, keyboard interaction is not possible.)
The following table describes the behaviors of certain fields set to FB_VIEWABLE:
Field Type
Behavior
Control button
A single primary mouse-click displays the option menu, if one exists. End users may view the contents of the option menu, including its shortcut menus. However, the events associated with each menu item will not be generated.
Multiline entry field
If it has scroll bars, end users can scroll the contents of the multiline entry field into view.
List field
End users can scroll the contents of the list field into view.
Option field
End users can display the entire value list of the option field.
Table field
End users can scroll through the contents of the table field.
Tree view
End users can scroll through the contents of the tree view field and expand and collapse its nodes.
Viewport
End users can scroll through the contents of the viewport field.
Note:  Those fields not listed are assumed to have the same behaviors as when they have the FB_VISIBLE bias.
Select Biases
FB_FLEXIBLE
Specifies that end users can select the field with the mouse and can move or resize the field
FB_RESIZABLE
Specifies that end users can select the field with the mouse and can resize the field but not move it
FB_MOVEABLE
Specifies that end users can select the field with the mouse and can move the field but not resize it
FB_MARKABLE
Specifies that end users can select the field with the mouse but cannot move or resize the field. The field changes to reverse video when selected.
Draw Biases
FB_CLICKPOINT
Specifies that the field can take a ClickPoint event (allowing you to discover exact cursor coordinates)
FB_DRAGBOX
Specifies that end users can draw a drag box through the field
FB_DRAGSEGMENT
Specifies that end users can drag a line segment through the field
For more information about using field biases and frame modes in your 4GL code, see the Programming Guide.