If you create a custom item with an entry ID that does not exist in the Item.dbc, it will be displayed as a red question mark:
[li][SIZE=14px]It cannot be enchanted[/SIZE][/li]
[li][SIZE=14px]It cannot be added to the action bar[/SIZE][/li][li][SIZE=14px]It cannot be right-clicked from your inventory to equip it in your character panel[/SIZE][/li][li][SIZE=14px]It will disappear when placed into a bank or guild vault slot (visual bug only)[/SIZE][/li][li][SIZE=14px]If the item is a weapon, spells that require a weapon cannot be used (ex. Sinister Strike, Hamstring, etc.)[/SIZE][/li][/ul]
[SIZE=14px]Solution #1: Use unused items from the item.dbc[/SIZE]
One solution is to use unused item entry #s from the item.dbc file. The client knows that these items exist, but they’re most likely NPC items (not available to players):
[li][SIZE=14px]Gregarious’ importable table of unused item.dbc items: [/SIZE]item_dbc_unused.sql[/li]
[li]Rochet2’s list of unused items: http://pastebin.com/sirbRBJY[/li]
[li]ragmanii’s list of unused items: http://www.trinitycore.org/f/topic/2687-guide-the-truth-about-custom-items-and-the-big-red-question-mark/#entry59125[/li]
Notes on this solution: While you are freely able to use the entries above for your item, the client will still fight you over the display model if you decide to change it. When you first log in with your new item, it will look fine. However, if you delete your cache and log back in, the item will appear to be the original unchanged item until you relog again. Relogging will force your client to load the custom displayId into your cache, thus showing you the new display you gave it. Also, other players will see the default display if they delete their cache as well. Thankfully, this is rather temporary, as a simple relog will get the item to show your edit as opposed to the original.
Furthermore, the item’s default icon display will show up while it is in your bags, but if the item is equipped, it will convert its icon to the new displayId you gave it. For this reason, it is recommended to use items in either option above that look similar to the one you’re making. Example: If you’re making an axe, try to find an unused axe for your new item’s entry ID.
[SIZE=18px]Solution #2: Create and distribute a new patch containing a modified item.dbc[/SIZE]
This process is explained in more detail in this thread. Other information can be found by Googling “trinitycore custom item dbc patch”, or similar.
The advantages with this solution include:
[li]Unlimited item entry #s[/li][li]All of the problems above in “The Problem” section above no longer apply[/li][li]All items become a “real” item that the game recognizes 100%[/li][/ul]
The disadvantage, however, might be enough not to use this solution: All of the players on your server will need to download this patch in order to interact with your custom items. For those of you forcing the use of a custom launcher in order to play on your servers, this is not a problem as you could set the launcher to download the additional content patch. However, for other server administrators who do not have or want to require a launcher, this is not a recommended solution.