What does this error mean in asp.net 2.0 and C#

My site is built in ASP.NET 2.0 and C# using SQL 2005 Database. I am writing all the error to my db in table called Exceptions.

Lately I have noticed that on my Products page, this error keeps getting written to the Exception table a lot. And I am not able to replicate it, if I want to check it out.

 System.NullReferenceException: Object reference not set to an instance of an object. at MySite.products.showItems(Int32 pageIndex) in c:\Websites\gn4f4ada\browse\products.aspx.cs:line 547 at MySite.products.Page_Load(Object sender, EventArgs e) in c:\Websites\gn4f4ada\browse\products.aspx.cs:line 68

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in products.aspx.cs line 68 is

   try
            {
                if (!this.IsPostBack)
                {
                    this.CategoryId = Convert.ToInt32(Request[REQ_CATEGORY_ID]);
                    this.showItems(this.PageIndex);  // THIS IS LINE 68
                }
            }
            catch (Exception ex)
            {
                this.HandlePageError(ex);
            }

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and line 547

     private void showItems(int pageIndex)
        {
            Category view;
            if (SelectedSize > -1)
            {
                view = this.CurrentCategory.GetView(
                    (SizeType)SelectedSize,
                    (Gender)SelectedGender);
            }
            else
            {
                if (SelectedGender > 0)
                {
                    view = this.CurrentCategory.GetView((Gender)SelectedGender);
                }
                else
                {
                    view = this.CurrentCategory;
                }
            }

            this.pager.SetPagingLabels(view.ItemCount);  // THIS IS LINE 547

            if (this.ViewMode == MySitePage.ViewMode.Paged)
            {
                this.rProducts.DataSource = view.GetPage(pageIndex, this.pager.PageSize);
            }
            else
            {
                this.rProducts.DataSource = view.Items;
            }
            this.rProducts.DataBind();
        }

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any advice or suggestions are appreciated
LVL 2
niceoneishereAsked:
Who is Participating?
 
RainverseConnect With a Mentor Commented:
It means view.ItemCount is Null at that point. Possibly because it's before postback?

-MJC
0
 
käµfm³d 👽Commented:
Is either pager or view null at the point the exception is raised? Have you tried stepping through your code?
0
 
Meir RivkinConnect With a Mentor Full stack Software EngineerCommented:
first of all since you know this could happen, check view variable before calling this.pager.SetPagingLabels:
if(view == null){
throw new Exception("Nullable view.....");
}

this.pager.SetPagingLabels(view.ItemCount);  

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in the exception you throw here, add additional data which will tell you what might be the problem (like SelectedSize, SelectedGender etc).
i'd go and create custom exception but its not really necessary for this case.

i assume its something with this.CurrentCategory.GetView() which might returns null.
if you knew what is the value of SelectedSize and SelectedGender , you could have known which case is about.

so i'd start with that.
post here if you have any updates.
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Monica PConnect With a Mentor Software DeveloperCommented:
this.CategoryId = Convert.ToInt32(Request[REQ_CATEGORY_ID]);

check  if Request[REQ_CATEGORY_ID]) contains value..

and then convert into int32..
sometime This may also produce error....

if not request(rea_category_id) =nothing then
  this.CategoryId = Convert.ToInt32(Request[REQ_CATEGORY_ID]);
endif
0
 
niceoneishereAuthor Commented:
The problem is I am not able to replicate it. It only shows up in the Exception Table
0
 
RainverseCommented:
That's because you're doing error handling.
0
 
niceoneishereAuthor Commented:
Thanks
0
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