How can I save global application variables in WPF?

Question

In WPF, where can I save a value when in one UserControl, then later in another UserControl access that value again, something like session state in web programming, e.g.:

UserControl1.xaml.cs:

Customer customer = new Customer(12334);
ApplicationState.SetValue("currentCustomer", customer); //PSEUDO-CODE

UserControl2.xaml.cs:

Customer customer = ApplicationState.GetValue("currentCustomer") as Customer; //PSEUDO-CODE

ANSWER:

Thanks, Bob, here is the code that I got to work, based on yours:

public static class ApplicationState
{
    private static Dictionary<string, object> _values =
               new Dictionary<string, object>();
    public static void SetValue(string key, object value)
    {
        if (_values.ContainsKey(key))
        {
            _values.Remove(key);
        }
        _values.Add(key, value);
    }
    public static T GetValue<T>(string key)
    {
        if (_values.ContainsKey(key))
        {
            return (T)_values[key];
        }
        else
        {
            return default(T);
        }
    }
}

To save a variable:

ApplicationState.SetValue("currentCustomerName", "Jim Smith");

To read a variable:

MainText.Text = ApplicationState.GetValue<string>("currentCustomerName");

Solution 1

Something like this should work.

public static class ApplicationState 
{ 
    private static Dictionary<string, object> _values =
               new Dictionary<string, object>();

    public static void SetValue(string key, object value) 
    {
        _values.Add(key, value);
    }

    public static T GetValue<T>(string key) 
    {
        return (T)_values[key];
    }
}

Solution 2

You can expose a public static variable in App.xaml.cs file and then access it anywhere using App class..

Comments

[0x12]

Where do we going to implement this class? and is this implementation Thread Safe ?