private static string GetOption(SelectSources optionSource, SelectSources source)
 {
     return $"<option{ GetSelected(optionSource, source) }>HtmlEncode[[{ optionSource.ToString() }]]</option>";
 }
 private static string GetSelected(SelectSources optionSource, SelectSources source)
 {
     return optionSource == source ? " selected=\"HtmlEncode[[selected]]\"" : string.Empty;
 }
 private static string GetExpectedSelectElementWithPrefix(SelectSources source, bool allowMultiple)
 {
     return $"<select id=\"HtmlEncode[[Prefix_Property1]]\"{ GetMultiple(allowMultiple) } " +
         "name=\"HtmlEncode[[Prefix.Property1]]\">" +
         $"{ GetOption(SelectSources.ModelStateEntry, source) }{ Environment.NewLine }" +
         $"{ GetOption(SelectSources.ModelStateEntryWithPrefix, source) }{ Environment.NewLine }" +
         $"{ GetOption(SelectSources.ViewDataEntry, source) }{ Environment.NewLine }" +
         $"{ GetOption(SelectSources.PropertyOfViewDataEntry, source) }{ Environment.NewLine }" +
         $"{ GetOption(SelectSources.ViewDataEntryWithPrefix, source) }{ Environment.NewLine }" +
         $"{ GetOption(SelectSources.PropertyOfViewDataEntryWithPrefix, source) }{ Environment.NewLine }" +
         $"{ GetOption(SelectSources.ModelValue, source) }{ Environment.NewLine }" +
         $"{ GetOption(SelectSources.PropertyOfModel, source) }{ Environment.NewLine }" +
         "</select>";
 }