anxious! !! !! !! !! Please master help!

jevons1022

A website in Chinese and English,
I use a single page for the news. I have a title picture on the list page and the detailed page.
What I originally thought was that the header image was loaded through skinid dynamic +
But it can't be realized now, others say that because I use it in a custom control, it doesn't work.
I took the picture and put it on a template page, but it still didn't work.

 protected void Page_PreInit (object sender, EventArgs e)
    {
        //Choose a language
        string lang = null;
        if (Session ["lang"] == null || Session ["lang"]. ToString () == "")
        {
            lang = "0";
            this.Theme = emailclass.StyleSheetTheme.selectlang (lang);

        }
        else
        {
            lang = Session ["lang"]. ToString ();
            this.Theme = emailclass.StyleSheetTheme.selectlang (lang);

        }

        switch (Request.QueryString ["newstyp"]) // Select the picture to display according to the news type parameter
        {
            case "01": // 01 Industry Focus
                Image1.SkinID = "info_ifocus";
                break;
            case "02": // 02 News
                Image1.SkinID = "info_inews";
                break;
            case "03": // 03 Media Advertising
                Image1.SkinID = "info_imedia";
                break;
            case "04": // 04 Product Promotion
                Image1.SkinID = "info_iporducy";
                break;
            ...
        }
    }


    
    protected void Page_Load (object sender, EventArgs e)
    {
        ...
    }

The above is the code part.
I wonder, what is the problem?
Very anxious, please master help!

qwer000

Page_PreInit
Before initialization? Was there a problem with this incident? You changed it here, will it revert to the default value during initialization? You put it in PAGE——LOAD, or other events after initialization

jevons1022

It seems there is no problem with this event because a template page is used

acadia

When did I teach you to put these codes in the Page_PreInit event???

jevons1022

The results are:

Theme, does not support dynamic addition

I had to write another class, the address of the picture used inside, no skinid

Thank you all for your help!