Question

In my program I have three distinct UI states (Normal, Success, and Error) and in each one the controls are visible/hidden, enabled/disabled, the colors change, labels say different things…etc. and in my code-behind I basically want to be able to say ChangeWindowState(UI.Normal);

So my question is how best to implement the control changes for each state?

Of course I could manually change the controls in the code-behind, but I wonder if maybe there is a better way by using wpf themes or styles. Then maybe I could just set the window to use the ‘Error’ theme, which I have pre-defined. I don’t really understand them at the moment so I may be using the terminology wrong, but I would appreciate if someone could point me in the right direction how best to do something like this.

Thanks!

Answer 1

There are many ways to approach this, of course. If you had a program-state ‘object model’ you could use some combination of DataTemplates and DataTriggers. Assuming this is not the case, here’s another approach: You referred to a window, so suppose you define a ‘dependency property’ in your window class like this:

public partial class Window1 : Window {     public Window1()     {         this.InitializeComponent();          // Insert code required on object creation below this point.     }      public ProgramStatus ProgramStatus     {         get { return (ProgramStatus)GetValue(ProgramStatusProperty); }         set { SetValue(ProgramStatusProperty, value); }     }      // Using a DependencyProperty as the backing store for ProgramStatus.  This enables animation, styling, binding, etc...     public static readonly DependencyProperty ProgramStatusProperty =         DependencyProperty.Register('ProgramStatus', typeof(ProgramStatus), typeof(Window1), new UIPropertyMetadata(null)); }  public enum ProgramStatus {     Normal,     Success,     Error } 

Now you can change pretty much any property of any element of the window (including the window itself), by either direct binding or a trigger. Here’s an example of changing the window’s background color via a property trigger:

<Window     xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'     xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'     xmlns:l='clr-namespace:Test'     x:Class='Test.Window1'     x:Name='Window'     Title='Window1'     Width='640' Height='480'>     <Window.Style>         <Style TargetType='{x:Type l:Window1}'>             <Style.Triggers>                 <Trigger Property='ProgramStatus'>                     <Trigger.Value>                         <l:ProgramStatus>Error</l:ProgramStatus>                     </Trigger.Value>                     <Setter Property='Background' Value='Red' />                 </Trigger>                 <Trigger Property='ProgramStatus'>                     <Trigger.Value>                         <l:ProgramStatus>Normal</l:ProgramStatus>                     </Trigger.Value>                     <Setter Property='Background' Value='Blue' />                 </Trigger>                 <Trigger Property='ProgramStatus'>                     <Trigger.Value>                         <l:ProgramStatus>Success</l:ProgramStatus>                     </Trigger.Value>                     <Setter Property='Background' Value='Green' />                 </Trigger>             </Style.Triggers>         </Style>     </Window.Style>     <Grid x:Name='LayoutRoot'/> </Window>