I have a requirement to create a custom datalist. I created it via creating new datalist xml file and associated files. If want to add a new field in this datalist I need to go and edit the datalist xml file.
Can I have any other solution for adding fields in the datalist without editing the xml file?
No, you must edit content model XML in order to modify or create new data lists if you are using Alfresco out-of-the-box.
If you want to try one of the content model management tools available at http://addons.alfresco.com you might be able to use one of those to change the data list schema without manually editing XML.