[This is preliminary documentation and is subject to change.]
Represents a placed element on an on-screen Layout.
Declaration Syntax| C# |
public class Placement : Persistent, IOrderable
Members| All Members | Methods | Properties | Fields | Events | |
| Icon | Member | Description |
|---|---|---|
 | Adopt(Persistent, IReference%, Int32) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
 | Adopted | Occurs when this object is adopted as a contained (not
associated) child object of another object. (Inherited from Persistent.) |
 | AllowedFormats | The set of Formats that this Placement
is allowed to use. |
| AnnotationSeparator | This string is used to separate the text in NominativeText and DiscriminativeText properties
(Inherited from Persistent.) |
| Associate(Persistent, IReference%, Int32) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
| Associated | Occurs when this object is taken as an associated child object
of another object. (Inherited from Persistent.) |
| AssociatorCount()()()() | Gets the number of associations made to this object. (Inherited from Persistent.) |
| BaseClassReference(Persistent, Reference) |
Here only to allow consistent use of new keyword in generated classes.
Always throws an exception.
(Inherited from Persistent.) |
| CallTree(CallTreeData, Int32) | In derived classes, calls a particular delegate for every node in
a persistent tree. (Inherited from Persistent.) |
| CallTree(CallTreeData) | Starts a recursive descent of the persistent containment tree
from this object, calling a delegate for every node in the tree below this
object. (Inherited from Persistent.) |
| Caption | The caption to be shown alongside the control for this placement
in the user interface. |
| Class | Gets the ObjectClass object associated with this object. (Overrides Persistent.Class.) |
| ClassFlags | Gets the class flags for the Placement class. (Overrides Persistent.ClassFlags.) |
| Clone()()()() | Creates a copy of this object. (Inherited from Persistent.) |
 | Collection()()()() | Creates a Placement collection to contain provisional objects. |
| Collection(Persistent, FlagSet, Int32, Boolean) | Creates a Placement collection to contain persistent objects. |
| ContainingEnvironment | Gets the Environment that this object is contained within.
(Inherited from Persistent.) |
| CopyFrom(Persistent) | Copies values of fields from another Persistent of the same type.
(Inherited from Persistent.) |
| CopyTransientFrom(Persistent) | Allows derived classes to copy transient data when CopyFrom is called. (Inherited from Persistent.) |
| Database | Gets the Database object for the database in which
this object is or is to be stored. (Inherited from Persistent.) |
| DeAssociateFrom(Persistent, Int32) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
| Deleted | This event occurs when an object is deleted. (Inherited from Persistent.) |
| DeleteVolatile(IReference) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
| DePersist(Object) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
| DePersistFrom(IPersistateList, Object) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
| DeReference(Persistent) | Returns this object. (Inherited from Persistent.) |
| DiscriminativeText | Gets a string containing values of discriminative properties. (Overrides Persistent.DiscriminativeText.) |
| Disowned | Occurs when this object is disowned from being a contained (not
associated) child object of another object. (Inherited from Persistent.) |
| Dissociated | Occurs when this object is removed from being an associated child
object of another object. (Inherited from Persistent.) |
| Equals(Persistent) | Determines if this Persistent is equal to another. (Inherited from Persistent.) |
| Equals(Object) | (Inherited from Object.) |
| FillFromDatabase(Database, IDataReader) | This method is intended for use only from generated code, and
you should not use it in open code. (Inherited from Persistent.) |
| FillFromMessage(Message) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
 | Finalize()()()() |
Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection.
(Inherited from Object.) |
| Format | The Format that has been chosen to be used to show the Member for this Placement. |
| GeneratedFormat | The Format that was selected for this Placement the last time
that source code was generated for the Layout. |
| GetAssociators()()()() | Gets a collection of all objects which have associations to this
object. (Inherited from Persistent.) |
| GetChildren<(Of <<'(T>)>>)(IndexedList<(Of <<'(T>)>>), ObjectClass, FlagSet, Int32, String, array<Object>[]()[][]) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
| GetChildren<(Of <<'(T>)>>)(IndexedList<(Of <<'(T>)>>), ObjectClass, String, array<Object>[]()[][]) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
| GetDefaultLayout()()()() |
Finds the default layout for this object. This will always be
of layout type Form.
(Inherited from Persistent.) |
| GetFieldValue(Int32) | Gets the value of the field backing the member with a particular slot number. (Overrides Persistent.GetFieldValue(Int32).) |
| GetHashCode()()()() |
Serves as a hash function for a particular type.
(Inherited from Object.) |
| GetKey(Int32) | Returns property value for given key number. (Overrides Persistent.GetKey(Int32).) |
| GetMemberValue(Int32) | Gets the value of the member property with a particular slot number. (Overrides Persistent.GetMemberValue(Int32).) |
| GetSelected<(Of <<'(T>)>>)(IndexedList<(Of <<'(T>)>>), ObjectClass, array<Object>[]()[][]) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
| GetType()()()() |
Gets the Type of the current instance.
(Inherited from Object.) |
| InitialiseMembers(Boolean, Boolean) | In derived classes, initialises members of the Persistent object.
(Inherited from Persistent.) |
| IsAttached | Determines whether this object is attached to the persistent
tree. (Inherited from Persistent.) |
| IsDistributedFrom(Persistent) | Determines whether this object is held or is to be held in a
different Database than another object. (Inherited from Persistent.) |
| IsEmpty | Determines whether this is the Empty object of its class, as
returned by the EmptyObject
property. (Inherited from Persistent.) |
| IsForeign | Gets a value determining whether this object is originally from a
Domain other than the local Domain. (Inherited from Persistent.) |
| IsInvalid | Gets a value indicating the validity of the current state of this
object. (Inherited from Persistent.) |
| IsModified | Gets a value indicating whether this object has been modified
(Inherited from Persistent.) |
| IsPersisted | Gets a value indicating whether the object has been persisted
in a Database.
(Inherited from Persistent.) |
| IsProvisional | Gets a value indicating whether this object is still provisional
- has not been persisted in a Database. (Inherited from Persistent.) |
| ItsObjectClass | Gets the ObjectClass object associated with this class. |
 | locker |
This object is used to synchronise fetches of contained objects and collections
in generated code.
(Inherited from Persistent.) |
| Member | The Member that this placement shows in the Layout.
|
| MemberwiseClone()()()() |
Creates a shallow copy of the current Object.
(Inherited from Object.) |
| Modified | Occurs when an object is modified. (Inherited from Persistent.) |
| Move(String, Persistent, String) | Moves this object from its current parent object to a new one.
(Inherited from Persistent.) |
| Move(String, Persistent, String, Int32) | Moves this object from its current parent object to a new one,
optionally inserting it at a particular position in a collection.
(Inherited from Persistent.) |
| NominativeText | Gets a string containing values of nominative properties. (Overrides Persistent.NominativeText.) |
| ObjectNumber | This returns the object number part of the object's Reference.
(Inherited from Persistent.) |
 | OnModified()()()() | Raises events signalling that the current object has been
modified. (Inherited from Persistent.) |
| Order | The order of this Placement in the Placements collection. |
| OwningDomain |
Gets the Domain to which this object originally belongs.
(Inherited from Persistent.) |
| Parent | This returns the parent object of this one. (Inherited from Persistent.) |
| ParentLayout | Gets the Parent object as a Layout. |
| ParentReference | Gets a Reference to this object's parent object.
(Inherited from Persistent.) |
| PreviousVersion | Returns the previous version of this object. (Inherited from Persistent.) |
| ReadOnly | Whether the user will be able to modify data using the control
generated for this Placement. |
| Refresh()()()() | Gets the current value of this object from persistent storage.
(Inherited from Persistent.) |
| RefreshAndLock()()()() | Gets the current value of this object from persistent storage and
sets a database lock. (Inherited from Persistent.) |
| RefreshTree()()()() | Refreshes the entire persistent containment tree under this
object. (Inherited from Persistent.) |
| RestoreUnmodified(Boolean) | Restores the values of an object's members to those of the
previous version. (Inherited from Persistent.) |
| SaveToDatabase(Database, Reference, Object) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
| SaveToMessage(Message) | Saves this Persistent object to a Message.
(Inherited from Persistent.) |
| SaveToMessage(Message, Boolean) | Saves this Persistent object to a Message.
(Inherited from Persistent.) |
| SetFieldValue(Int32, Object) | Sets the value of the field backing the member with a particular slot number. (Overrides Persistent.SetFieldValue(Int32, Object).) |
| SetMemberFromMessage(Int32, Int32, Message) | This method is intended for use only from generated code, and you
should not use it in open code. (Inherited from Persistent.) |
| SetMemberValue(Int32, Object) | Sets the value of the member property with a particularn slot number. (Overrides Persistent.SetMemberValue(Int32, Object).) |
| SetModified()()()() | Signals to Persistate that an object has been modified. (Inherited from Persistent.) |
| SetModifiedSynced()()()() | Signals to Persistate that an object has been modified. The call
is protected by a lock on this object. (Inherited from Persistent.) |
| StoreInDatabase(Database) | Marks this object so that it will be stored in a particular Database. (Inherited from Persistent.) |
| SubLayout | The sub-layout which will be used for this Placement, it the Format requires one. |
| ThisObj | This property is used in binding combo box selected values. It
returns the current object. (Inherited from Persistent.) |
| TitleText | Gets a title for this object. (Inherited from Persistent.) |
| ToMetaReference()()()() | Creates a MetaReference referring to this object,
if possible. (Inherited from Persistent.) |
| ToMetaReference(Boolean) | Creates an environment relative MetaReference
referring to this object, if possible. (Inherited from Persistent.) |
| ToReference()()()() | Obtains a Reference to this Object. (Inherited from Persistent.) |
| ToString()()()() | Constructs a string describing the Placement.
(Overrides Persistent.ToString()()()().) |
| Traverse(String) | Traverses the persistent object graph from this object using a
period delimited navigation path. (Inherited from Persistent.) |
| Validate()()()() |
Allows inheritors to create a validation method for Persistent classes.
(Inherited from Persistent.) |
| VersionNumber | Gets the version number of this object. (Inherited from Persistent.) |
| WriteTestAssociations(IClassified, Int32, CreateTestDataParameterSet) | Creates test association(s) for an associated member of this
object. (Inherited from Persistent.) |
| WriteTestData(Persistent, Int32, CreateTestDataParameterSet) | Fills this object with test data. (Inherited from Persistent.) |
RemarksPlacements are part of the Persistate scheme to implement a user interface (the View in the Model/View/Controller architecture) which is both completely decoupled from the Controller, but also independent of the type of user interface. By this latter, we mean for example windows forms based, web based, XAML based, mobile based, etc..
There is one Placement for each Member of an ObjectClass which is portrayed in a Layout in the user interface. A Placement results in a column in a grid or a control on a form. If the Member is an object, then the Placement's SubLayout determines how the object is portrayed, for example in a sub-form. The placement also contains a Caption which becomes a label for a control or heading for a column.
The way in which the Member is shown is determined by the Placement's Format. This can be, for example, a text box or spinner for an integer member, or a sub-form or form access button for an object Member. The latter two would require a SubLayout to be selected, the first two would not. You normally choose a Placement's Format and if necessary SubLayout using the Persistate add-in.
For now, there is a fixed set of Formats. A scheme to allow plug-in Formats is planned.
Inheritance Hierarchy| Object | ||
 | Persistent | |
| Placement | |