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IPartialPersist Interface
See Also  Members   Example
Chili.Opf3 Namespace : IPartialPersist Interface




This interface that is implemented by objects that are partually persisted.

Syntax

Visual Basic (Declaration) 
Public Interface IPartialPersist
Visual Basic (Usage)Copy Code
Dim instance As IPartialPersist
C# 
public interface IPartialPersist
Managed Extensions for C++ 
public __gc __interface IPartialPersist
C++/CLI 
public interface class IPartialPersist

Example

The following example shows how to implement the interface and use it in combination with the IObjectNotification interface.
C#Copy Code
             [Persistent("Users")] 
public sealed class User : IPartialPersist, IObjectNotification 
{ 
   private Dictionary<string, bool> _changes; 
    private string _name; 
 
    [Field("Name")] 
    public string Name 
    { 
        get { return _name; } 
        set  
        {  
            _name = value; 
 
            // Signalize that the property has changed. 
            SignalizeChange("Name"); 
        } 
    } 
 
    // ... Other properties of the persistent. 
     
    // Signalizes that a property with the given name has been changed. 
    private void SignalizeChange(string propertyName) 
    { 
        // Adds the changed property to the dictionary. 
        if (_changes != null && !_changes.ContainsKey(propertyName)) 
            _changes.Add(propertyName, true); 
    } 
 
    #region IObjectNotification Members 
 
    void IObjectNotification.OnAfterPopulated(ObjectNotificationEventArgs e) 
    { 
        // Initializes the dictionary holding the changes after having 
        // finished to populate the persistent object. 
        _changes = new Dictionary<string, bool>(); 
    } 
 
    // ... Other methods of the interface. 
 
    #endregion 
 
    #region IPartialPersist Members 
 
    // Returns whether a member is to persist. 
    bool IPartialPersist.IsMemberToPersist(string name, PersistentOperations operation) 
    { 
        // Returns if whether the dictionary contains the property. 
        return _changes.ContainsKey(name); 
    } 
 
    // Gets whether the persistent instance has members to persist. 
    bool IPartialPersist.HasMembersToPersist 
    { 
        get { return _changes.Count > 0; } 
    } 
 
    #endregion 
}

Remarks

This interface is implemented by classes that are partually persisted. It allows the persistent to specify if any members are to persist and return for each member whether to persist. This interface allows to do powerful change tracking and updating of only changed members if combined with the IObjectNotification interface.

Requirements

Namespace: Chili.Opf3

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: Chili.Opf3 (in Chili.Opf3.dll)

See Also