Last week, I had the opportunity to explore the user interface of sandbox project. Mr. Peter assigned me a few tasks, one of which was to add a filter to an entity list in the view model, incorporating search functionality and page numbers. As usual, he provided me with a code example of a complete view model to learn from, which was very helpful.
From studying the example view model, I identified several important aspects that I should pay attention to. These include dependency injection, data binding, mapping, working with a DataGrid, and handling events.
Dependency injection, as I mentioned last week, is a crucial concept in the MVVM architecture. It promotes loose coupling, enhances maintainability, and facilitates testing. In the context of the view model, dependency injection involves providing the required dependencies (such as services, data repositories, or other objects) to the view model from an external source, typically through constructor parameters.
The use of a datagrid in the view model suggests that the view presents tabular data or a grid-like structure. A datagrid is a UI control that enables the display and manipulation of tabular data, typically in the form of rows and columns. The view model would provide the necessary data and commands to populate and interact with the datagrid in the view.
Data binding is another essential aspect of MVVM. It establishes a connection between the view and the view model, allowing for seamless synchronization of data changes between the two. With data binding, it bind properties of UI elements in the view to properties in the view model. When the bound properties change in the view model, the corresponding UI elements in the view automatically update, and vice versa.
Mapping is often used in view models to transform and adapt data between different representations. During a method that specifically require mapping, the entities are retrieved from the data source, mapped to view models using AutoMapper, and further processed or filtered as needed. Finally, the view models are assigned as the data source for the view, allowing them to be bound to UI controls and displayed to the user. Since I’m using AutoMapper, I also needed define mapping profiles that specify how properties from a source object should be mapped to properties in a destination object. These profiles can be configured with mapping rules, such as explicitly defining how specific properties should be mapped or specifying custom transformations using lambda expressions.
Lastly, events play a crucial role in MVVM for handling user interactions and notifying the view model of various actions or state changes. Events can be raised in the view when certain user actions occur, such as button clicks or selection changes, and the view model subscribes to these events to perform the appropriate actions or update its internal state accordingly.
Overall, by understanding these concepts and their application in the example view model had assist me in implementing the requested features, that is adding a filter with search functionality and pagination to the entity list in the sand box user interface.