RE: RE: RE: RE: RE: [DUG]: Interface question

[Matthew Evans]

Its creating a new interface object yes, but I’m not using IInterfaceList The Get_items is as follows :   function TDataSightVariableList.Get_Items(     Index: Integer): IDataSightVariable; begin     with FVariableList,VarInterface do begin         Description := Items[Index].Description;         DisplayName := Items[Index].DisplayName;         FieldName := Items[Index].FieldName;         FieldID := Items[Index].FieldID;         Units := Items[Index].Units;         FieldFormat := Items[Index].FieldFormat;         FieldType := integer(Items[Index].FieldType);         Fixed := Items[Index].Fixed;         MarkedForDelete := Items[Index].MarkedForDelete;         MarkedForSave := Items[Index].MarkedForSave;         Size := Items[Index].Size;     end;     Result := VarInterface; end;   -----Original Message----- From: Kyley Harris [mailto:[EMAIL PROTECTED]] Sent: Tuesday, 28 January 2003 11:54 a.m. To: Multiple recipients of list delphi Subject: RE: RE: RE: RE: [DUG]: Interface question   interesting.   is your Get_Items(i) creating a new interface object each time it is accessed by mistake? i would assume that in the background you are using an IInterfaceList to contain a set of interfaces so that each subsequent call returns the same object which includes the modified property value.   Get_Items(i); begin result := FList.Items[i] as IDisp..... end;   if you use Set_Items you will lose reference to one, and gain reference to the new -----Original Message----- From: Matthew Evans [mailto:[EMAIL PROTECTED]] Sent: Tuesday, 28 January 2003 11:30 a.m. To: Multiple recipients of list delphi Subject: RE: RE: RE: [DUG]: Interface question Ok this is what is happening: Items[i].MyProp:= ‘MyValue’; So first Get_items is called , this returns the interface with all the properties set from Fitems[i] After the interface is returned, Set_MyProp is called and assigned the value ‘MyValue’. So now the interface has the new value but this interface is not returned to Items[i]   Not sure if this helps clear up what my problem is but I’m hoping so.   -----Original Message----- From: Kyley Harris [mailto:[EMAIL PROTECTED]] Sent: Tuesday, 28 January 2003 10:38 a.m. To: Multiple recipients of list delphi Subject: RE: RE: [DUG]: Interface question   He isn't trying to write 'MyValue' into Set_Items in that example set_items is never called.   items[i].MyProp calls Get_Items(i) returning an interface. then it is trying to assign 'MyValue' to MyProp -----Original Message----- From: Conor Boyd [mailto:[EMAIL PROTECTED]] Sent: Tuesday, 28 January 2003 10:24 a.m. To: Multiple recipients of list delphi Subject: RE: [DUG]: Interface question Hi Matthew,   Your Set_Items method is expecting a reference to an interface (IDataSightVariable).  You're passing it a string ('MyValue') in the example you gave.  The example you gave about creating an interface and setting the property values is therefore the expected behaviour.   Do you want to give a bit more code for us to have a look at?   Cheers,   Conor     -----Original Message----- From: Matthew Evans [mailto:[EMAIL PROTECTED]]   Here's my problem, I have a property that returns an interface. The interface has several properties. I can read these properties fine showmessage(Items[i].MyProp); for example. However if I want to set said interface property I can't. Items[i].MyProp:= 'MyValue'; will not call the set method. So the only way I can set Interface values is first create an interface set the property values then assign it to the items list items[i]:= MyInterface; Only been playing with these for a small amount of time and wondering how I should be going about this so I can read and write the interface properties right off the list? Any takers.   function Get_Items(Index: Integer): IDataSightVariable; safecall; procedure Set_Items(Index: Integer; const Value: IDataSightVariable); safecall; property Items[Index: Integer]: IDataSightVariable read Get_Items write Set_Items;