CODEWITHSUNDEEP
c#
Lmg94
Lmg94

Reputation: 1

Why does my windows phone app crash on button click?

I am making a pet shop app for windows phone 7 in visual studios 2010. I am trying to get the items from one page that have already been copied to the temporary list in app.xaml (can see this in the debugger) to display in my other list on the basket page but when the button to direct to the basket page is clicked the application crashes. I did not use binding for any part of the app

 private void btnAdd_Click(object sender, RoutedEventArgs e)
    {
        thisApp.petBasket.Add(lstAllPets.SelectedItem as Pets);
        MessageBox.Show("Item added to the Basket");
    }

this is the code used to add the item to the temporary list

    public void ShowBasket()
    {
        if (thisApp.petBasket != null)
        {
            //show pets that have been added to the basket
            foreach (Pets currpet in thisApp.petBasket)
            {
                lstBasketItems.Items.Add(currpet.Name + "" + currpet.Gender + "" + currpet.Dob + "" + currpet.Category + "");
            }
        }
    }

this is the code I am using to try and output the items but it makes the app crash

Does anyone know what the problem might be ?

Upvotes: 0

Views: 95

Answers (1)

Marius Bancila
Marius Bancila

Reputation: 16338

Your app might be crashing because your pet basket contains nulls.

thisApp.petBasket.Add(lstAllPets.SelectedItem as Pets);

If the selected item is not a Pets then operator as returns null and you put that in the list. Later on you just iterate without checking for nulls.

foreach (Pets currpet in thisApp.petBasket)
{
    lstBasketItems.Items.Add(currpet.Name + "" + currpet.Gender + "" + currpet.Dob + "" + currpet.Category + "");
}

You should check the selected item.

var pet = lstAllPets.SelectedItem as Pets;
if(pet != null)
    thisApp.petBasket.Add(pet);

You could also check currpet in your foreach loop.

Upvotes: 1

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