Add Drop Files

[diluculo]

My feature request #231

[tgjones]

Seems like this logic should be shared with OpenFileCommandHandler?

[diluculo]

@tgjones Yes, you are right. Please see the #237, where TryActivateDocumentByPath( ) is introduced. If needed, I can add the method into this PR.

OpenFileCommandHandler.cs:

[CommandHandler]
public class OpenFileCommandHandler : CommandHandlerBase<OpenFileCommandDefinition>
{
    ...
    public override async Task Run(Command command)
    {
        ...
        if (dialog.ShowDialog() == true)
        {
            var fullPath = Path.GetFullPath(dialog.FileName);

            if (!_shell.TryActivateDocumentByPath(fullPath))
                _shell.OpenDocument(await GetEditor(fullPath));

            // Add the file to the recent documents list
            _shell.RecentFiles.Update(fullPath);
        }
    }
    ...
}

ShellViewModel.cs:

[Export(typeof(IShell))]
public class ShellViewModel : Conductor<IDocument>.Collection.OneActive, IShell
{
    ...
    public bool TryActivateDocumentByPath(string path)
    {
        foreach (var document in Documents.OfType<PersistedDocument>().Where(d => !d.IsNew))
        {
            if (string.IsNullOrEmpty(document.FilePath))
                continue;

            var docPath = Path.GetFullPath(document.FilePath);
            if (string.Equals(path, docPath, StringComparison.OrdinalIgnoreCase))
            {
                OpenDocument(document);
                return true;
            }
        }

        return false;
    }
    ...
}