Wednesday, November 7, 2012

Visiting dashboards

DashboardView is a type of XAF View that is used to display several Views side-by-side. However XAF by default does not provide any connection between these Views. In this post, with the help of XAF model, we will discuss a few abstract connection mechanisms and possible uses of dashboards.

Cascading ListViews

In a dashboard, in order to connect the ListViews we need first to connect their models. This can be done using the following interfaces,

public interface IModelDashboardViewFilter : IModelNode {

 

    [DataSourceProperty("FilteredColumns")]

    IModelColumn FilteredColumn { get; set; }

 

    [DataSourceProperty("DataSourceViews")]

    IModelListView DataSourceView { get; set; }

}

[ModelAbstractClass]

public interface IModelDashboardViewItemEx : IModelDashboardViewItem {

    IModelDashboardViewFilter Filter { get; }

} 

and then extend XAF’s model, see also our documentation on extending the model

public void ExtendModelInterfaces(ModelInterfaceExtenders extenders) {

    extenders.Add<IModelDashboardViewItem, IModelDashboardViewItemEx>();

}

This design allows us to use Model Editor to connect our views. In the following image we see that the selected objects of the Customer_ListView_Calendar are going to filter the Calendar list view on the Receipt.Customer field.

image

Next we see this dashboard view in action, a SchedulerListEditor on the right is filtered by a GridListEditor,

image

Following we see this technic applied to 3 ListViews. The selected pie section of the left View filters the pivot which in its turn filters a LayoutListEditor!

image

Cascading views are as well useful for filtering reports, so by selecting objects on the left View we create a report on the right view and everything is inside a Tabbed MDI environment!

image

Of course we haven’ wrote the code yet but this is the easy part. XAF’s API is so rich and so well designed that is like we speak our native language! The great thing when XAFing is that our code is fully reusable from any project since it has no knowledge of our domain objects.

Let try to form our requirement in English first:
For each ListView in a Dashboard we need to filter another View when the selection is changed

And now in XAF language Smile:

protected override void OnViewControlsCreated() {

    base.OnViewControlsCreated();

    foreach (var result in View.Items.OfType<DashboardViewItem>()) {

        var frame1 = result.Frame;

        if (frame1 != null && frame1.View is ListView) {

            var listView = ((ListView)frame1.View);

            DashboardViewItem result1 = result;

            listView.SelectionChanged += (sender, args) => OnSelectionChanged(new SelectionChangedArgs(listView, result1));

        }

    }

void OnSelectionChanged(SelectionChangedArgs selectionChangedArgs) {

    var dataSourceListView = DataSourceListView((IModelListView)selectionChangedArgs.DashboardViewItemModel.View);

    if (dataSourceListView != null) {

        var dashboardViewItems = View.Items.OfType<DashboardViewItem>();

        foreach (var dashboardViewItem in dashboardViewItems) {

            var modelDashboardViewItemEx = (IModelDashboardViewItemEx)dashboardViewItem.GetModel(View);

            FilteredListView(dataSourceListView, dashboardViewItem, modelDashboardViewItemEx);

        }

    }

Controlling DashboardViewItem visibility

Cascading views are really powerful and soon we will have the need to hide an intermediate view in the chain but being able to filter other views upon it. Therefore we need to add a Visibility property in our model and handle it from our code.

public interface IModelDashboardViewItemEx : IModelDashboardViewItem {

    [DefaultValue(ViewItemVisibility.Show)]

    ViewItemVisibility Visibility { get; set; }

and in a reusable from all projects controller implement the required logic.

protected override void OnActivated() {

    base.OnActivated();

    ((ISupportAppearanceCustomization)View.LayoutManager).CustomizeAppearance += LayoutManagerOnCustomizeAppearance;

 

}

void LayoutManagerOnCustomizeAppearance(object sender, CustomizeAppearanceEventArgs customizeAppearanceEventArgs) {

    var modelDashboardViewItem = View.Model.Items.OfType<IModelDashboardViewItemEx>().FirstOrDefault(item => item.Id == customizeAppearanceEventArgs.Name);

    if (modelDashboardViewItem != null)

        ((IAppearanceVisibility)customizeAppearanceEventArgs.Item).Visibility = modelDashboardViewItem.Visibility;

}

Displaying HTML Messages

A DashboardView does not have direct dependency with our domain objects. Therefore we can easily use it, even at runtime, to display static text view items and other controls (ControlDetailItem) or images (StaticImage).

image

XAF has great support for HTML Formatting so a Static Text like “<u><b>Hello</b></u>” will render the following:

image

Simulating View inheritance

XAF does not support View inheritance however we can extend our model and support it. Lets take the case that we have a very complex listview and we want to display it in both in MasterDetail and ListViewOnly modes without the need to support two View versions. For this we have to extend again the model, this time by a MasterDetailMode property and implement the logic in a ViewController.

[ModelAbstractClass]

public interface IModelDashboardViewItemEx : IModelDashboardViewItem {

    MasterDetailMode? MasterDetailMode { get; set; }

public class DashboardInteractionController : ViewController<DashboardView>, IModelExtender {

    protected override void OnViewControlsCreated() {

        base.OnViewControlsCreated();

        ResetMasterDetailModes();

    }

    void ResetMasterDetailModes() {

        foreach (var masterDetailMode in _masterDetailModes) {

            masterDetailMode.Key.MasterDetailMode = masterDetailMode.Value;

        }

        _masterDetailModes.Clear();

    }

 

    protected override void OnActivated() {

        base.OnActivated();

        foreach (var item in View.GetItems<DashboardViewItem>().Select(item => item.GetModel(View)).OfType<IModelDashboardViewItemEx>()) {

            AssignMasterDetailModes(item);

        }

    }

 

    void AssignMasterDetailModes(IModelDashboardViewItemEx modelDashboardViewItem) {

        if (modelDashboardViewItem.MasterDetailMode.HasValue) {

            var modelListView = modelDashboardViewItem.View as IModelListView;

            if (modelListView != null) {

                _masterDetailModes.Add(modelListView, modelListView.MasterDetailMode);

                modelListView.MasterDetailMode = modelDashboardViewItem.MasterDetailMode.Value;

            }

        }

    }

Since XAF has a great modularization system the core classes/implementations of the above ideas are included in this zip file. However we will not update the contents of the zip file. For locating up to date versions each file in the zip has an OnlineRepoLocation attribute that points to eXpandFramework’s Github repository.

This post adds a few more tools in our development library that can leverage the XAF power using the Model. When we “model” there are three basic advantages:

  1. We can use these model tools at runtime. For this XAF already provides a runtime time Model Editor.
  2. We create robust unbreakable code and since we model instead of developing we mostly have no bugs only wrong configuration!
  3. Implementations are reusable from all our projects!

Next post we will boost our R&D times even further and discuss a bit about Security system policies.

P.S.: We are preparing detailed samples demonstrating all the above ideas Smile, stay tuned!

If some of you have invented similar ways to connect your dashboards. You can use our support center and share them with the rest of the community.

Happy XAFing!

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