Showing a PopUp in an ASP.Net before Page_load

I am developing an ASP.net application in which i am suppose开发者_如何学运维d to show a select language Popup( a simple screen where user can select language) to the user when he logs in for the first time. I tried calling the PopUp from the InitializeCulture event but the PopUp appears after the home Page Gets loaded.

I want the PopUp to appear before the page is loaded. Once the user selects the language from the PopUp, i want the page to appear in that language.

I am using the following code the call the PopUp

Page.ClientScript.RegisterStartupScript(typeof(Page), "onload", script);

Have the user redirected to a select language page. Then redirect to the site afterwards. You can also check on page load to be sure a language has been selected or redirect to the page.

To provide some explanation of Chad's response, it helps to understand the core of the ASP.NET Page Life Cycle. In particular, when an aspx page is requested from the server for the first time (i.e. not a post-back), IIS recognizes the .aspx extension and hands it off to the ASP.NET engine for rendering. The ASP.NET engine first instantiates the code-behind class, executes any pre-render methods or events (Init, Page_Load, PreRender, etc.), and also processes all of the non-HTML markup ('<%...%>' and '') in the .aspx file. When all of this is done, it has the complete HTML page that is then returned to the browser in the HTTP response).

The point here is that the browser never sees any of your HTML, including the RegisterStartupScript code, until after your Page_Load or any other server-side code has already completed.

Another possible solution is to use a MultiView which shows the language selection UI in one View and the actual page content in another view. The language selection would now be done via controls directly on the page rather than in a pop-up. In your Page_Load, you check to see if a language has been selected and if not, show the first View. After the user selects their language, is submits a post-back to the server which calls the Page_Load a second time (this time with IsPostBack being true). You then set the language in your code based on the user's selection and switch to the second View that contains the main page content. You may also get a slightly better user experience by wrapping the MultiView in an UpdatePanel so you get AJAX post-backs, instead of full-page ones.

So the basic logic in your Page_Load would look something like this (using C# like syntax):

if (!IsPostBack) {
    string userLang = SomehowGetSelectedLanguageFromUserProfile(); // You provide
    if (String.IsNullOrEmpty(userLang) {
        PopulateLanguageComboBox();  // You provide
        multiView1.ActiveView = 0;
    } else {
        DoAnyWorkNecessaryToRenderPageInSpecifiedLanguage(userLang); // You provide
        multiView1.ActiveIndex =1;
    }
} else {
    if (multiView.ActiveView == 0)
    {
        if (comboLangSelect.SelectedIndex <= 0) {
            lblErrorMessage.Text = "You must select a language to continue";
            lblErrorMessage.Visible = true;
        } else {
            DoAnyWorkNecessaryToRenderPageInSpecifiedLanguage(comboLangSelect.SelectedValue); 
            multiView1.ActiveIndex =1;
        }
    } else {
        // Any other PostBack processing required for the main page.
    }
}

Please note that I wrote this entirely here in the response box and have not compiled nor tested this in any way. It is only meant to provide you the general logic behind the solution I am suggesting.

If you really need to do the language selection in a pop-up, it can be done, but then you need to have the pop-up window communicate the results back to the main page window and have it manually post-back the results to the server. This is a little more involved but it is possible.