Hello. I am working through Scott Mitchell's ASP.Net in 24 hours book. I am finishing the photo album project.
I have a GridView that retrieves a list of uploaded photo rows for the logged-in user.
The GridView is for editing and deleting rows.
The photo Category field in the Gridview is a dropdown list. The text entry field was deleted after converting this field to a Template.
Like the uploaded photos, these Categories are user-specific. They are created in another web page.
Users also have the option to select "none" for the category when they upload an image.
For the GridView: The Category ID field's ItemTemplate and EditItemTemplate both have a " - None - " choice added to them.
I am getting this error:
'pictureReadOnlyCategories' has a SelectedValue which is invalid because it does not exist in the list of items. Parameter name: value
Note: The ID for the ItemTemplate for that dropdown list is the ID listed above in the error: "pictureReadOnlyCategories".
Am I missing some step in this process of changing a GridViews text field to a dropdown that can be used for editing? I went through the book's instructions three times.
Here is my code for the dropdown list and a screenshot of the Design
View Complete Post