Wpf data binding update

It allows the flow of data between UI and business model. Any modification done on data in your business model after binding is done, will automatically reflect to the UI, and vice versa. Binding can be one directional or bidirectional. The source of databinding can be a normal.

NET property or Dependency property, however the target property must be a Dependency property. For making binding work properly, both sides of the property must provide a change in notification which will tell the binding to update the target value. The new database will now appear in Server Explorer, right-click on it and select New Query. Copy the following SQL into the new query, then right-click on the query and select Execute.

Select Data from the left menu and then ADO. Select the connection to the database you created in the first section, enter ProductContext as the name of the connection string and click Next.

Once the reverse engineer process completes the new model is added to your project and opened up for you to view in the Entity Framework Designer. An App. EF generates code from your model using T4 templates. The templates shipped with Visual Studio or downloaded from the Visual Studio gallery are intended for general purpose use. However, when doing data binding using WPF it is desirable to use ObservableCollection for collection properties so that WPF can keep track of changes made to the collections.

To this end we will to modify the templates to use ObservableCollection. Find the ProductModel. These are located approximately at lines and This occurrence is located approximately at line Do not replace the second occurrence of HashSet found later in the code. This is located approximately at line Save the ProductModel.

This should cause the code for entities to be regenerated. If the code does not regenerate automatically, then right click on ProductModel. If you now open the Category. EF gives you an option of loading related entities from the database automatically the first time you access the navigation property. With this type of loading called lazy loading , be aware that the first time you access each navigation property a separate query will be executed against the database if the contents are not already in the context.

When using POCO entity types, EF achieves lazy loading by creating instances of derived proxy types during runtime and then overriding virtual properties in your classes to add the loading hook. To get lazy loading of related objects, you must declare navigation property getters as public and virtual Overridable in Visual Basic , and your class must not be sealed NotOverridable in Visual Basic.

When using Database First navigation properties are automatically made virtual to enable lazy loading. In the Code First section we chose to make the navigation properties virtual for the same reason. The Data Sources window is opened next to the MainWindow.

Press the pin icon, so the Data Sources window does not auto hide. You may need to hit the refresh button if the window was already visible. Now that we have a grid to display Categories let's add a details grid to display the associated Products. Remember, C is a case-sensitive language, so the label defined in MainWindow. It is exposed and accessed using get and set accessors. The private fields simply hold the values for the public properties. To do this, your class will need to implement the INotifyPropertyChanged interface.

ComponentModel namespace, so you will need to add the namespace via a using directive. ComponentModel; Recall when you learned about delegates that delegates can be used in event handling to pass values to the UI thread. The OnPropertyChanged method should receive as a parameter the name of the property that is being changed. Line 41 is equivalent to OnPropertyChanged "Counter" ;.

Finally, write the OnPropertyChanged method. When the PropertyChanged event is raised, this method will instantiate an object containing the name of the property that was changed so the UI control can connect to the appropriate property. CompilerServices namespace. In this case, you can invoke OnPropertyChanged without passing any attributes. Simply change the method definition as follows. CompilerServices; directive and define a default value for the propertyName parameter in order to use CallerMemberName.

You can simplify the OnPropertyChanged method by replacing the if not null condition with a null-conditional member access operator?. Following is what your completed code should resemble: using System; using System. Generic; using System.