Building OpenPOS: Part 9 – Settings and Notifications

A common topic I see on StackOverflow is how do I persist my window location in a WPF-friendly manner?

First things first, let's create some default values:

“The .NET Framework 2.0 allows you to create and access values that are persisted between application execution sessions.” – MSDN

Once we have some defaults, all we have to do is bind to them from our window! Sounds easy, huh?

First, include the default namespace…

xmlns:local="clr-namespace:OpenPOS.Properties"

And then bind to them:

<Window x:Class="OpenPOS.Views.ShellView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:OpenPOS.Properties"
        Height="{Binding Source={x:Static local:Settings.Default}, Path=Height, Mode=TwoWay}" 
        Width="{Binding Source={x:Static local:Settings.Default}, Path=Width, Mode=TwoWay}"
        Left="{Binding Source={x:Static local:Settings.Default}, Path=Left, Mode=TwoWay}" 
        Top="{Binding Source={x:Static local:Settings.Default}, Path=Top, Mode=TwoWay}"
        WindowState="{Binding Source={x:Static local:Settings.Default}, Path=WindowState, Mode=TwoWay}">

</Window>

and that’s it!

Another common question I see often is how do I handle dialog boxes, etc? The easy answer to this is just call MessageBox.Show, ShowDialog, etc! and it will work in simple applications but what happens if you need to test this? Now you depend on a Dialog box that pops up or some user interaction! In OpenPOS, I create services for these kind of interactions! I created a VERY simple NotifyService for sending notifications:

public interface INotifyService
{
    void Notify(string message);
}

And this is how the notification looks:

BTW – this uses wpf-notifyicon (and here is a CodeProject article on how to use it).

For more information about OpenPOS…

• Building OpenPOS- Part 1 - Introduction
• Building OpenPOS- Part 2 - Rapid prototype using SketchFlow
• Building OpenPOS- Part 3 – Scaffolding and Navigation
• Building OpenPOS- Part 4 – SalesModule (Part 1)
• Building OpenPOS- Part 5 – SalesModule (Part 2)
• Building OpenPOS- Part 6 – Make it look pretty…
• Building OpenPOS- Part 7 – NoSQL, MSSQL, SQL CE-
• Building OpenPOS- Part 8 - Windows 7 love

And you can download ALL the source from CodePlex here.

CodeProject