>Hi,
>
>I have a delete button on a WPF form which I only want enabled whenever one and only one item is selected in a grid on the same form. I figure I have to do something like this:
>
>IsEnabled="{Binding ElementName=grdManifest, Path=Items.Selected.Count = 1}"
>
>but that isn't accepted as valid code.
>
>Any ideas on how to do this?

I think you will need to add a property to your viewmodel. Something like:

public bool EnableButton
        {
            get { return grdManifest.SelectedItems.Count == 1; }
        }

then bind:

IsEnabled="{Binding Path=EnableButton}"

(untested :-{)

UPDATE: You probably need to trigger a PropertyChanged on the EnableButton:

void grdManifest_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            PropertyChanged(this,new PropertyChangedEventArgs("EnableButton"));
        }