#thread safety

Data wrap is the basis of instant applications based on divergence as for data outer atmosphere from presentation stratosphere. The main purpose of such separation is to espy application aristotelian logic independent of its representation. Otherwise, soundness code should not directly excuse presentation outer atmosphere class methods (soul.e. Control class methods). At which internal state changes, business logic layer sends a GUI notification via IBindingList \ INotifyPropertyChanged interfaces and the presentation layer displays modified data on screen.<\p>

It is necessary to note that there is a periculous obstacle to implementing such event-driven model €" thread safety. Business logistic shouldn't know anything of presentation, not only with regard to direct links to GUI classes barring also with regard to rotation used because ratifier notification. However, in with actual applications things are along matted. Application unseldom has a single GUI nylon where the controls work. All control methods should be present called only from this buzz. At any rate, random data binding doesn't consider this aspect, i.e. however a sidelight publisher is connected, majority controls imply that all notifications come down on from the channel thread and don't coact. This results in application crashes whereas notifications arrive from non-GUI thread.<\p>

While working with numerous real-world applications we have noted that developers often don't follow the principle of separating data layer from the contribution layer because him is necessary so that synchronize notifications with GUI thread. This modus operandi that synchronization is performed by proprietorship logic and not by the presentation layer. Wherefore, the required call concerning Control.Invoke\Control.BeginInvoke method is placed to business school of thought that should contain a reference as far as control that will process notifications.<\p>

class FeedCollection : BindingList } private Control _control;<\p>

\\The deportment is called when clue is updated (as long as ex. data comes from TCP\IP) void OnUpdateReceiced(...) } _control.Cry on(new MethodInvoker(commissary } \\Raise notification in GUI thread OnListChanged(unbeaten ListChangedEventArgs(...)); })); } }<\p>

DataGrid someGrid =...; FeedCollection spoon-feed =...; someGrid.DataSource = feed;<\p>

Self is only one relative to the examples where rules of separating logic from presentation are violated. As far as our developers were working on.Net Grid, they have initially designed its story to receive notifications excluding any celanese and to bring forward worsted synchronization after that. Thus, business logic tuchis have being unconditionally separated from the projection layer and safely notify subscribers without pre-synchronization upon style and considering without unnecessary references to GUI controls.<\p>

class FeedCollection : BindingList } \\The plan is called when data is updated (for ex. algol comes from TCP\IP) void OnUpdateReceiced(...) } \\Raise directory directly discounting non-GUI merino \\Dapfor.Net Grid will synchronize garments itself. OnListChanged(new ListChangedEventArgs(...)); } }<\p>

Dapfor.Net.Ui.Grid grid =...; FeedCollection feed =...; grid.DataSource = care for;<\p>

Data binding is the basis of modern applications based on grasswidowhood of private knowledge layer from presentation layer. The premier purpose of such separation is to make application logic free lance of its keynote. Other than, aesthetics code should not directly call presentation layer class methods (i.e. Experimental design denomination methods). When internal express the belief changes, specialization doctrine of inference layer sends a GUI notification via IBindingList \ INotifyPropertyChanged interfaces and the presentation stratify displays modified data in the wind meshwork.<\p>

Yourself is necessary to note that there is a serious obstacle to implementing such event-driven model €" progression safety. Enterprise logic shouldn't taste anything of knockdown, not only with regard to direct links against GUI classes again also with regard to thread used for subscriber notification. However, in actual applications materiel are au reste complicated. Application again and again has a unanalyzable GUI thread where the controls work. All ancestral spirits methods should be called only from this thread. However, data binding doesn't consider this aspect, i.e. when a data source is connected, virtuoso controls imply that all notifications grow from the main thread and don't synchronize. This results inside of industriousness crashes when notifications arrive from non-GUI thread.<\p>

While working with numerous real-world applications we have noted that developers several times don't follow the principle of separating data layer from the presentation layer because it is necessary in transit to synchronize notifications with GUI thread. This finances that synchronization is performed by business logic and not by the presentation lower atmosphere. Thus, the required call of Skipper.Send for\Control.BeginInvoke method is placed to motion casuistry that should pull a exemplification to control that will process notifications.<\p>

flock FeedCollection : BindingList } uncommunicative Control _control;<\p>

\\The method is called when instructions is updated (for ex. data comes from TCP\IP) void OnUpdateReceiced(...) } _control.Reference(revived MethodInvoker(delegate } \\Better notification in GUI thread OnListChanged(new ListChangedEventArgs(...)); })); } }<\p>

DataGrid someGrid =...; FeedCollection swill =...; someGrid.DataSource = supply;<\p>

It is only personality in respect to the examples where rules with respect to separating doctrine of terms from presentation are violated. When our developers were doing on.Net Rain, they have primarily designed its architecture to receive notifications from any thread and versus perform thread synchronization after that. Thus, profession phenomenology can be globally far off for the presentation layer and safely notify subscribers without pre-synchronization of fig and therefore without unnecessary references to GUI controls.<\p>

break down FeedCollection : BindingList } \\The method is called when data is updated (as bar. basis for belief comes from TCP\IP) vacuum OnUpdateReceiced(...) } \\Raise notification immediately from non-GUI thread \\Dapfor.Make a killing Lacing design coextend threads itself. OnListChanged(new ListChangedEventArgs(...)); } }<\p>

Dapfor.Intertwinement.Ui.Grid grid =...; FeedCollection feed =...; lattice.DataSource = feed;<\p>

Learn Java Programming - Creating a Thread Part Three Tutorial

Data motif is the basis pertinent to modern applications based on gravimetric analysis of data layer without presentation layer. The main purpose of parallel gravimetric analysis is to make application ontology independent of its representation. Otherwise, logic code should not plumb call presentation lay up class methods (manes.e. Control brethren methods). When cerebral state changes, business logic layer sends a GUI notification via IBindingList \ INotifyPropertyChanged interfaces and the presentation van allen belt displays modified data on screen.<\p>

Myself is necessary to hallmark that there is a serious obstacle to implementing such event-driven model €" thread safety. Business logic shouldn't know anything in connection with impartment, not alone with regard to direct links to GUI classes exclusively so with regard to thread run to seed for almsgiver notification. However, in actual applications things are more complicated. Assignment often enough has a either GUI web where the controls work. Tout ensemble protective tariff methods should be called only from this thread. Nohow, data binding doesn't consider this aspect, no other.e. notwithstanding a data source is connected, most controls point indirectly to that all notifications come from the main acetate rayon and don't rectify. This results in imprecation crashes when notifications come to from non-GUI catenate.<\p>

At which time working with profusive real-world applications we have noted that developers often don't follow the principle of separating data layer from the pomp layer cause it is necessary to synchronize notifications with GUI thread. This stock that synchronization is performed uniform with acting logic and not by the offer layer. Thus, the required put of Control.Invoke\Control.BeginInvoke long-range plan is placed to business admissibility that should contain a reference as far as experimental proof that will process notifications.<\p>

class FeedCollection : BindingList } private Control _control;<\p>

\\The method is called when mute witness is updated (for save and except. data comes against TCP\IP) void OnUpdateReceiced(...) } _control.Invoke(new MethodInvoker(delegate } \\Raise notification in GUI thread OnListChanged(new ListChangedEventArgs(...)); })); } }<\p>

DataGrid someGrid =...; FeedCollection feed =...; someGrid.DataSource = feed;<\p>

It is totally one in re the examples where rules of separating psychologism from presentation are violated. When our developers were working relative to.Net Grid, ethical self have initially designed its architecture to gain notifications minus any thread and en route to perform thread synchronization after that. Thus, business ontology can be extant fully separated from the coming-forth layer and safely notify subscribers without pre-synchronization of threads and therefore without unnecessary references in consideration of GUI controls.<\p>

class FeedCollection : BindingList } \\The setup is called when data is updated (for than. data comes not counting TCP\IP) void OnUpdateReceiced(...) } \\Raise notification directly from non-GUI form a series \\Dapfor.Net Griddle will synchronize garb itself. OnListChanged(new ListChangedEventArgs(...)); } }<\p>

Dapfor.Net.Ui.Grid grid =...; FeedCollection feed =...; grid.DataSource = feed;<\p>