How to update table in SQL Server with Entity Framework?

Not entirely sure what you're trying to do.... assuming you want to update the whole table, you could try something like this:

• load the whole table into memory as a List<StcDocItems>
• loop over each item and see if it has a matching entry - if so, update it

So this would be the code to do this:

public class StcDocItems
{
    public int Id { get; set; }
    public int PartRef { get; set; }
    public int DocRefType { get; set; }
    public int? ItemRef { get; set; }
}

using(YourDbContext ctx = new YourDbContext())
{
    // get all rows from table
    List<StcDocItems> allItems = ctx.StcDocItems.ToList();

    // iterate over items
    foreach(StcDocItems item in allItems)
    {
        // do we find a row which has "ItemRef = Id" and "DocTypeRef = 63" ?
        StcDocItems updateToItem = allItems.FirstOrDefault(i => i.ItemRef = item.Id && i.DocTypeRef = 63);

        // if we found an item
        if(updateToItem != null)
        {
            // set the partRef to new item's partRef
            item.PartRef = i.PartRef;
        }
    }

    // save any changes back to database table
    ctx.SaveChanges();
}  

Update StcDocItems set partRef =366 where itemRef=id and DocTypeRef =63