WPF – Individual dialog states using ClientGuid

A new ClientGuid property, introduced with .NET 8, allows you to uniquely identify dialogs such as the OpenFileDialog and the OpenFolderDialog, with the purpose of storing state – such as window size, position and last used folder – separately per dialog.

To benefit from this behavior, configure the ClientGuid of your dialog to a known identifier before calling the ShowDialog() method.

static readonly Guid _id = new Guid("32bc5a4c-e28f-408a-8aca-e0b430fbc17c");

var dialog = new OpenFileDialog 
{
    ClientGuid = _id
};

dialog.ShowDialog();

The dialog state is persisted across different runs of the application and even across different apps, all that matters is that the ClientGuid is the same.

Note: Make sure you use the same identifier across different application instances. Do not generate the Guid at runtime using Guid.NewGuid() since that will result in a new Guid every time you run the application, and your dialog state will reset. Instead, store the Guid as in the example above, or create a KnownDialogs class specifically for the purpose of storing dialog identifiers.