using statement in codebehind - wpf

Question

When editing the c# programs I have the top that includes namespaces with the using keyword. Such as using System;.
I have some classes that are redundantly implemented across my WPF application. I would like to create a single reference point to use the methods within the whole application.
for instance when I perform data binding for ComboBoxes I have a class that includes this...
public class ComboBoxItemSource : ViewModelBase
{
public ObservableCollection<Item> Source { get; set; }
public Item Selected { get; set; }
}
I would like to have this in one place and include it in a reference rather than create it in each ViewModel that will need a combobox binding.

Answer 1

I'd recommend to just put the class in a separate file and add it to your project.
Or even simpler:
Right click on your project in the Solution Explorer -> "Add new Item" -> "Class".
Copy/Paste your class into the file
Adjust the namespace
Add the missing usings to the file (especially the using for the "View Model Base")
The class including the namespace in the file will now look similar to this:
namespace MyNamespace
{
public class ComboBoxItemSource : ViewModelBase
{
public ObservableCollection<Item> Source { get; set; }
public Item Selected { get; set; }
}
}

Answer 2

You could do something like this.
Create an IComboBox interface:
public interface IComboBox
{
ObservableCollection<Item> Source { get; set; }
Item Selected { get; set; }
}
then you could create a Class that inherits from your ViewModelBase and implements your IComboBox:
public class ComboBoxVM :ViewModelBase, IComboBox
{
public ObservableCollection<Item> Source
{
get
{
// do stuff
return _source;
}
set { _source = value; }
}
public Item Selected
{
get
{
// do stuff
return _selected;
}
set { _selected = value; }
}
}
then in your ComboBoxItemSource, inherit from ComboBoxVM:
public class ComboBoxItemSource : ComboBoxVM
{
}
Hopefully this helps.