ListBoxItem produces “System.Windows.Data Error: 4” binding error

Question

I have created the fallowing ListBox:

Answer 1

Another workaround that worked for me was to suppress these errors (actually, it seems more appropriate to call them warnings) by setting the data binding source switch level as critical in constructor of the class or a top level window -

#if DEBUG     
    System.Diagnostics.PresentationTraceSources.DataBindingSource.Switch.Level =
        System.Diagnostics.SourceLevels.Critical;
#endif

Ref.: How to suppress the System.Windows.Data Error warning message

Update: This is not the best solution but for warnings which are harmful this looks good to me.