SharePoint is Flowers and Rainbows and Unicorns

One of our clients reported that after updating several items in a list with a BDC column everything seemed to break. They could still view the information since it is stored in the list item, however they could not add new or edit existing items in the list as the field was required. The list contained over 49,000 items (in folders) so recreating the list/field was not really an option. Without knowing the exact reason, it was determined that three fields within the BusinessDataField had been unset. These fields were: SystemInstanceName, EntityName, and BdcFieldName. Essentially the link had been broken back to the bdc. The solution, outlined below, was to update the field instance with the correct values.

The method used to determine the problem and fix it is fairly straightforward:

1. Find the error in the 12 hive logs, in our case it was this:

   System.ArgumentOutOfRangeException:   Parameter name: name     at Microsoft.Office.Server.ApplicationRegistry.MetadataModel.ApplicationRegistry.GetLobSystemInstanceByName(String name)...
   

2. Open reflector to the application registry object and examine the GetLobSystemInstanceByName method
   1. You will see that what throws that exception is if the name is either empty of longer than 255 characters
   2. This tells us that something is wrong with the SystemInstanceName property of that field in that list
3. Add a new BDC field to the list for the appropriate entity that is “broken”
4. Run the below code for both fields (or have it do both at once)

   SPSecurity.RunWithElevatedPrivileges(delegate()
   {
       SPList list = null;
   
       using (SPSite site = new SPSite("{siteURl}"))
       {
           using (SPWeb web = site.OpenWeb())
           {
               try
               {
                   list = web.Lists[new Guid("{listguid}")];
               }
               catch { }
           }
           site.RootWeb.Dispose();
   
           if (list != null)
           {
               BusinessDataField field = (BusinessDataField)list.Fields["{FieldName}"];
   
               if (field != null)
               {
                   Type t = field.GetType();
                   List<PropertyInfo> props = new List<PropertyInfo>(t.GetProperties());
   
                   props.ForEach(delegate(PropertyInfo p)
                   {
                       this.Cout(p.Name, p.GetValue(field, null));
                   });
               }
           }
       }
   });

5. Note what fields are incorrect or empty between the two outputs, in this case SystemInstanceName, EntityName, and BdcFieldName and note the correct values
6. Run the below code up update the field with the appropriate values

   SPSecurity.RunWithElevatedPrivileges(delegate()
   {
       SPList list = null;
   
       using (SPSite site = new SPSite("{siteURl}"))
       {
           using (SPWeb web = site.OpenWeb())
           {
               try
               {
                   list = web.Lists[new Guid("{listguid}")];
               }
               catch { }
           }
           site.RootWeb.Dispose();
   
           if (list != null)
           {
               BusinessDataField field = (BusinessDataField)list.Fields["{FieldName}"];
   
               if (field != null)
               {
                   field.SystemInstanceName = "{lob system instance name}";
                   field.EntityName = "{entity name}";
                   field.BdcFieldName = "{bdc field name}";
                   field.Update();
                   list.Update();
               }
           }
       }
   });

7. Test to ensure that functionality has returned
8. Delete column you created in step 1