Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Firstly, you don't need any of those toolkits/frameworks to implement MVVM. It can be as simple as this... let's assume that we have a <code>MainViewModel</code>, and <code>PersonViewModel</code> and a <code>CompanyViewModel</code>, each with their own related view and each extending an <code>abstract</code> base class <code>BaseViewModel</code>. </p> <p>In <code>BaseViewModel</code>, we can add common properties and/or <code>ICommand</code> instances and implement the <code>INotifyPropertyChanged</code> interface. As they all extend the <code>BaseViewModel</code> class, we can have this property in the <code>MainViewModel</code> class that can be set to any of our view models:</p> <pre><code>public BaseViewModel ViewModel { get; set; } </code></pre> <p>Of course, you'd be implementing the <code>INotifyPropertyChanged</code> interface correctly on <em>your</em> properties unlike this quick example. Now in <code>App.xaml</code>, we declare some simple <code>DataTemplate</code>s to connect the views with the view models:</p> <pre><code>&lt;DataTemplate DataType="{x:Type ViewModels:MainViewModel}"&gt; &lt;Views:MainView /&gt; &lt;/DataTemplate&gt; &lt;DataTemplate DataType="{x:Type ViewModels:PersonViewModel}"&gt; &lt;Views:PersonView /&gt; &lt;/DataTemplate&gt; &lt;DataTemplate DataType="{x:Type ViewModels:CompanyViewModel}"&gt; &lt;Views:CompanyView /&gt; &lt;/DataTemplate&gt; </code></pre> <p>Now, wherever we use one of our <code>BaseViewModel</code> instances in our application, these <code>DataTemplate</code>s will tell the framework to display the related view instead. We can display them like this:</p> <pre><code>&lt;ContentControl Content="{Binding ViewModel}" /&gt; </code></pre> <p>So all we need to do now to switch to a new view is to set the <code>ViewModel</code> property from the <code>MainViewModel</code> class:</p> <pre><code>ViewModel = new PersonViewModel(); </code></pre> <p>Finally, how do we change the views from other views? Well there are several possible ways to do this, but the easiest way is to add a <code>Binding</code> from the child view directly to an <code>ICommand</code> in the <code>MainViewModel</code>. I use a custom version of the <code>RelayComand</code>, but you can use any type you like and I'm guessing that you'll get the picture:</p> <pre><code>public ICommand DisplayPersonView { get { return new ActionCommand(action =&gt; ViewModel = new PersonViewModel(), canExecute =&gt; !IsViewModelOfType&lt;Person&gt;()); } } </code></pre> <p>In the child view XAML:</p> <pre><code>&lt;Button Command="{Binding DataContext.DisplayPersonView, RelativeSource= {RelativeSource AncestorType={x:Type MainView}}, Mode=OneWay}" /&gt; </code></pre> <p>That's it! Enjoy.</p>
    singulars
    1. This table or related slice is empty.
    1. POWPF MVVM navigate views
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USMike Fuchs
    1. USSheridan
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COI think this will work. But when i do ViewModel = new ... i get the error "ViewModel is a property, but is used as a type"
      singulars
      1. PO
      1. USuser2499088
    2. CODid you set the type of the `ViewModel` property to `BaseViewModel` and do your view models all extend that class?
      singulars
      1. PO
      1. USSheridan
    3. COWell i use MVVM Light so its all set to ViewModelBase, but all the viewmodels extend that class, and the property has the type ViewModelBase
      singulars
      1. PO
      1. USuser2499088
 

Querying!

 
Guidance
A row detail

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.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload