How can i find custom fields in a document library?

Question

Hi, guys.
I need your help, please.
My users sometimes creates custom columns i document libraries using the SharePoint GUI. That's fine, but I need to distinguish these columns from SharePoints own columns. So here's my task at hand:
I need to find all the fields (columns) for a document in a document library that were added by a user, i.e. NOT SharePoint standard fields. Is there a way to do this, like a property or something?
In my case, I have an event receiver triggering on ItemUpdated. The following snippet iterates through all fields of my item and I can read the item title and the item value.
How can I filter this to only show title and value of
custom fields?
foreach (SPField field in properties.ListItem.Fields)
string title = field.Title;
string value = string.Empty;
if (properties.ListItem[field.Title] != null)
value = properties.ListItem[field.Title].ToString();
// Do something with 'title' and 'value'
Again, the code above gives me ALL columns and I only want columns created by users. If it's possible, I'd like to skip custom content type fields.

Answer 1

Hi,
There is a custom column “CustomField1” in my library, after running the code, the output would be:
In fact, these fields do not exist in the
SPBuiltInFieldId object:
https://msdn.microsoft.com/en-us/library/microsoft.sharepoint.spbuiltinfieldid_members.aspx
As the documentation about these fields seems not being documented so well at this moment, to avoid the influence in your solution, you can exclude these fields explicitly
in the if block.
Thanks
Patrick Liang
Forum Support
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Patrick Liang
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