Enterprise Architecture MVVM Pattern Guide (WPF and Silverlight implementations) (3)

Chapter One Presentation pattern
Separation of concerns (SOC) is a very useful core principle in enterprise and software development, and also the driving force behind many performance models. In WPF and Silverlight development, MVVM became the most effective design pattern for separation of concerns. However, this pattern is relatively difficult to achieve compared to other presentation modes (MVC,MVP).
This chapter begins with an example of a bill that runs through the book. In the process of reviewing performance patterns, using each of these patterns to make your bill project more clear about their pros and cons, this will help you understand why you should use the MVVM pattern.
Example of application of Bill of Fare project
We start with the basic function of the bill item, and the UI for the bill application is as follows:

When the project drop-down list is selected, the other cost control and update buttons become available. As shown below:

Now the user is free to update the contents of any cost control, and if the user sets the actual cost below the budgeted cost and clicks the Update button, the budgeted cost content will turn green.

When the user sets the actual cost above the budgeted cost, clicking the Update button causes the budget cost content to turn red.

To be continue ...

Enterprise Architecture MVVM Pattern Guide (WPF and Silverlight implementations) (3)