Open Windows and Dialogs in MVVM

Open Windows and Dialogs using an ICommand. This repository uses the MVVM pattern in order to separate the View and the View Model, but maintaining the ability to open Windows.

For examples, check out the WindowCommands.Demo project in this repository.

Getting Started

1. Download and extract the solution.
2. Build the solution.
3. Add/Reference the WindowCommands project in your solution.

Start coding.

Open a Window

Firstly, create an OpenWindowCommand property in your view model:

public class MyViewModel
{
    public OpenWindowCommand OpenWindowCommand { get; private set; }

    public MyViewModel()
    {
        OpenWindowCommand = new OpenWindowCommand();
    }

    ...
}

Then, bind the OpenWindowCommand to a Button in your View:

<Button Content="Open Window"
        Command="{Binding OpenWindowCommand}"
        CommandParameter="{x:Type local:MyNewWindow}"/>

The CommandParamter is the Type of the Window you want to open.

Show a Dialog

A dialog is slightly different to a Window as a dialog will return a bool? result. The OpenDialogCommand requires an Action<bool?> callback method, here's an example:

public class MyViewModel
{
    public ShowDialogCommand ShowDialogCommand { get; private set; }

    public MyViewModel()
    {
        ShowDialogCommand = new ShowDialogCommand(PostOpenDialog);
    }

    /// <summary>
    /// This executes after the dialog is opened.
    /// </summary>
    public void PostOpenDialog(bool? dialogResult)
    {
        //TODO
    }
    
    ...
}

Once the dialog has been closed, the PostOpenDialog callback method will be called and the dialog result will be passed into the paramters.

Just like before, you can bind a Button to the command like so:

<Button Content="Show Dialog"
        Command="{Binding ShowDialogCommand}"
        CommandParameter="{x:Type local:MyDialogWindow}"/>

The PreOpenDialog overload

You may want to call a method before a dialog is displayed, in this case you can simply use the overload on the ShowDialogCommand constructor:

public class MyViewModel
{
    public ShowDialogCommand ShowDialogCommand { get; private set; }

    public MyViewModel()
    {
        ShowDialogCommand = new ShowDialogCommand(PostOpenDialog, PreOpenDialog);
    }

    /// <summary>
    /// This executes just before the dialog is opened.
    /// </summary>
    public void PreOpenDialog()
    {
        //TODO
    }
    
    /// <summary>
    /// This executes after the dialog is opened.
    /// </summary>
    public void PostOpenDialog(bool? dialogResult)
    {
        //TODO
    }
    
    ...
}

License

This project is under the MIT license.