WPF: dynamic menu with buttons - wpf

Question

I have a simple wpf-mvvm application where you can create and edit records. Something like this:
If you create a new record there are a "create" and "cancel" button.
If you edit an existing record there is a "edit", "delete" and "cancel" button.
I don't want to use two different form. I would like to use one, and create a dynamic menu, where I can choose which buttons are visible.
The xaml now is something like this:
<StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
<Button MinWidth="93" Command="{Binding CreateCommand}>
Create
</Button>
<Button MinWidth="93" Command="{Binding EditCommand}>
Edit
</Button>
<Button MinWidth="93" Command="{Binding DeleteCommand}>
Delete
</Button>
<Button MinWidth="93" Command="{Binding CancelCommand}>
Cancel
</Button>
</StackPanel>
What is the best way to do this?

Answer 1

I've had a similar situation. There are two options (at least, as always):
Use the CanExecute method of the commands and let them return true or false, depending on the type of record you want to edit. The CanExecute value toggles the IsEnabled property of the control it is bound to. This means, if you want to hide the control, you need to 'push' the IsEnabled value to the Visibility value, for example by using a style trigger.
<Style.Triggers>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Visibility" Value="Hidden"/>
</Trigger>
</Style.Triggers>
That would be the standard approach, I guess, and probably makes sense for you.
I had more dynamic circumstances and wanted to create the buttons dynamically. This can easily be done, when you define a Collection of CommandViewModels in your ViewModel. The CommandViewModel can have a name property which you display in a button and the command you want to execute. Then you can use this collection to populate an ItemsControl with buttons. Probably a bit of a overkill for your situation, but it refers to the title of your question and maybe you find it interesting and can use it at some point.
In short, the ViewModels:
public class CommandViewModel : ViewModelBase
{
public ICommand Command { get { return ... } }
public string Name { get; set; }
}
public class MainViewModel : ViewModelBase
{
...
ObservableCollection<CommandViewModel> Commands { get; private set; }
public MainViewModel()
{
Commands = new ObservableCollection<CommandViewModel>();
// Creates the ViewModels for the commands you want to offer
PopulateCommands();
}
}
And in the XAML looks something like:
<ItemsControl ItemsSource="{Binding Commands}"}>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Button Command="{Binding Command}" Content="{Binding Name}" />
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
That makes a dynamic menu...
Have fun.

Answer 2

If you are using MVVM, then you have a ViewModel which is your DataContext which contains the Create, edit, delete, and cancel commands.
Have your ViewModel have an instance of a record. If you edit it, pass in the instance to be edited. Else for creating a record set that to null.
Create your commands and have the CanExecute functionality check if the record that was passed in was null or not. (null represents Creating a new record, else editing). If you set the CanExecute of your commands to false, the buttons bound to it will automatically be disabled.