Theme XXX cannot be found in application directories or global themes

Question

My asp.net site allows users to select the theme they need from the list created in the app_themes folder. From time to time, topics are renamed or deleted. Any user who selects the name of a deleted topic (it is stored in a cookie) will receive an exception:

Theme 'XXX' cannot be found in the application or global theme directories Stack Trace: [HttpException (0x80004005): Theme 'test' cannot be found in the application or global theme directories.] System.Web.Compilation.ThemeDirectoryCompiler.GetThemeBuildResultType(String themeName) +920 System.Web.Compilation.ThemeDirectoryCompiler.GetThemeBuildResultType(HttpContext context, String themeName) +73 System.Web.UI.Page.InitializeThemes() +8699455 System.Web.UI.Page.PerformPreInit() +38 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +282 

Where is the best place to catch and handle this exception?

Answer 1

In the Page_PreInit method, where you assign topics, there are several ways to handle this. I am doing a check to make sure the directory exists. If so, then this is the topic I want. If this is not the case, use the default theme where I know the directory exists.

 void Page_PreInit(object sender, EventArgs e) { if (ViewState["PageTheme"] == null) { if (!Directory.Exists("~/App_Themes/THEMENAME_TO_LOOK_FOR")) { Theme = "DEFAULT_THEME" } else { Theme = "THEMENAME_TO_LOOK_FOR"; } ViewState["PageTheme"] = Theme; } else { Theme = ViewState["PageTheme"].ToString(); } } 

I usually store in a view, so I don’t need to double-check every time, but if you change themes on the fly, you probably don't need to do this.

Answer 2

if you use cookies to store a user-selected theme and you receive an error message “xxx'theme” not found in the local or global directory, then make sure your cookie name does not match with another cookie name.

Answer 3

You need to make sure that you change the user theme preference if they use your theme to rename / delete. If renamed, rename accordingly; if deleted, change the default theme. When you keep the theme preference inside cookies, you will need to check them and make changes to user access.