Question

Can’t figure this one out

I have an ArrayList of classes:

        // Holds an image
        public class productImage
        {
            public int imageID;
            public string imageURL;
            public DateTime dateAdded;
            public string slideTitle;
            public string slideDescrip;
        }

    public ArrayList productImages = new ArrayList();

productImage newImage = new productImage();
newImage.imageID = 123;
productImages.Add(newImage);

Now how do I access the property?

int something = productImages[0].imageID

Doesn’t work!

Error 1 ‘object’ does not contain a
definition for ‘slideTitle’ and no
extension method ‘slideTitle’
accepting a first argument of type
‘object’ could be found (are you
missing a using directive or an
assembly reference?)

Answer 1

The values in an ArrayList are typed to Object. You need to cast to productImage to access the property.

int something = ((productImage)productImages[0]).imageId;

A much better solution though is to used a strongly typed collection like List<T>. You can specify the element type is productImage and avoid the casting altogether.

public List<productImage> productImages = new List<productImage>();
productImage newImage = new productImage();
newImage.imageID = 123;
productImages.Add(newImage);
int something = productImages[0].imageID;  // Works