How to build a generic/re-usable modal dialog for WPF following MVVM

Question

I would like to build a generic/re-usable modal dialog that I can use in our WPF (MVVM) - WCF LOB application.

I have a Views and associated ViewModels that I would

Answer 1

I usually deal with this by injecting this interface into the appropriate ViewModels:

public interface IWindow
{
    void Close();

    IWindow CreateChild(object viewModel);

    void Show();

    bool? ShowDialog();
}

This allows the ViewModels to spaw child windows and show them modally on modeless.

A reusable implementation of IWindow is this:

public class WindowAdapter : IWindow
{
    private readonly Window wpfWindow;

    public WindowAdapter(Window wpfWindow)
    {
        if (wpfWindow == null)
        {
            throw new ArgumentNullException("window");
        }

        this.wpfWindow = wpfWindow;
    }

    #region IWindow Members

    public virtual void Close()
    {
        this.wpfWindow.Close();
    }

    public virtual IWindow CreateChild(object viewModel)
    {
        var cw = new ContentWindow();
        cw.Owner = this.wpfWindow;
        cw.DataContext = viewModel;
        WindowAdapter.ConfigureBehavior(cw);

        return new WindowAdapter(cw);
    }

    public virtual void Show()
    {
        this.wpfWindow.Show();
    }

    public virtual bool? ShowDialog()
    {
        return this.wpfWindow.ShowDialog();
    }

    #endregion

    protected Window WpfWindow
    {
        get { return this.wpfWindow; }
    }

    private static void ConfigureBehavior(ContentWindow cw)
    {
        cw.WindowStartupLocation = WindowStartupLocation.CenterOwner;
        cw.CommandBindings.Add(new CommandBinding(PresentationCommands.Accept, (sender, e) => cw.DialogResult = true));
    }
}

You can use this Window as a reusable host window. There's no code-behind:

You can read more about this (as well as download the full code sample) in my book.