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    <p>A very simple demo application demonstrating the general principle:</p> <pre><code>TModel = class property ValueList : TList &lt;Double&gt; read ... write ...; end; </code></pre> <p>You could then have multiple views that visualize the model, i.e. one view that displays the values in a table and one that displays the values in a diagram:</p> <pre><code>IView = interface ['{0D57624C-CDDE-458B-A36C-436AE465B477}'] public procedure Update; end; TTableView = class (TInterfacedObject, IView) private FModel : TModel; FController : TController; public procedure Update; end; TDiagramView = class (TInterfacedObject, IView) private FModel : TModel; FController : TController; public procedure Update; end; </code></pre> <p>The views do only read data from the model. All interaction with the GUI is delegated to the controller class (which uses the Observer design pattern by the way):</p> <pre><code>TController = class private FModel : TModel; FViewList : TList &lt;IView&gt;; private procedure UpdateViews; public procedure AddDataValue (Value : Double); end; </code></pre> <p>The implementation of AddDataValue could look something like:</p> <pre><code>procedure TController.AddDataValue (Value : Double); begin FModel.ValueList.Add (Value); UpdateViews; end; procedure TController.UpdateViews; var View : IView; begin for View in FViewList do View.Update; end; </code></pre> <p>This way you achieve multiple things:</p> <ul> <li>You can easily use multiple views (either allow the user to switch beetween views, or show them simultaneously)</li> <li>All data is in the model and completely separated from the presentation. Change the representation, change nothing in the model.</li> <li>To implement persistance you only have to save the model.</li> <li>You could use the controller to execute all necessary checks. (Instead of implementing this for each view)</li> </ul> <p>For a complete list of advantages, the web is full of discussion of the MVC pattern and its alternatives.</p> <p>In Delphi applications you may find that the controller is kind of overhead because of the event-based programming style in Delphi. What I often do is to only split my application into model and view.</p>
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    1. POWhat does an MVC Delphi with WebBroser and HTML application look like?
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    1. USjpfollenius
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    1. COAah, yes, now we're getting somewhere. So, in a Delphi application that only has a single TWebBrowser to show HTML, the controller could be the thing that pulls HTML from the 'view' and puts it in the WebBrowser component?
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      1. USStijn Sanders
    2. COI would see the webbrowser as the view displaying HTML. Another view for HTML might be a tree showing the structure of the HTML document.
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Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

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