Question

I use C# Asp.Net and EF 4.

I have a scenario like MasterPage and DetailsPage.

So from my MasterPage I pass a variable as a QeryString to the DetailsPage, the DetailsPage will show up details for a specifc item in my DataBase.

I need to check the validity for my QueryString, in details I need:

• Check if is Null, Empty or White Spaces.
• Check if is NOT of type INT (just numbers not any letters).
• Check if the Object NOT exists in my DB.

In case if Check result True, I will redirect the User.

At the moment I wrote this script. It is works but I would like to know if you know a better approch/code to solve this.

Also I would like to know if make sense to have this logic on every time the page Load, or would be enought us just on !Page.IsPostBack.

Thanks once again for your support guys!

   protected void Page_Load(object sender, EventArgs e)
    {
        #region Logic Check Query String.

        // Query String is Null or Empty.
        if (string.IsNullOrWhiteSpace(ImageIdFromUrl))
            RedirectToPage();

        // Query String is not valid Type of INT.
        int ImageId;
        bool isInt = Int32.TryParse(ImageIdFromUrl, out ImageId);
        if (isInt)
        {
            // Check if a valid Object request exist in Data Source.
            using (CmsConnectionStringEntityDataModel context = new CmsConnectionStringEntityDataModel())
            {
                if (!context.CmsImagesContents.Any(x => x.ImageContentId == ImageId))
                {
                    RedirectToPage();
                }
            }
        }
        else
            RedirectToPage();

        #endregion

    }

Answer 1

You don’t need to check it on every postback, only on a full page load. The query string is not sent to the server on postbacks.

I suggest you move all the query string validation logic to separate functions.