C# Newtonsoft Json data, value to assign empty list, so that the sqlcommand insert statement doesn't fail

We have some columns that are empty at times and we don't want the t-sql query to get null object reference error. One is the formattedNumber. What value do you assign to an empty json string so that the sqlcommand doesn't fail? //Example //many columns can be null //check for variable is null, if null assign a non value value so the insert and update statements don't fail, possibly dbnull IList<Landlines> personcommunicationlandlines = [login to view URL]; //if personcommunicationlandlines not null do this if (personcommunicationlandlines != null) { if ([login to view URL] > 0) { string formattedNumber = personcommunicationlandlines[0].formattedNumber; //Get id value of first element of array } else //Assign dbnull to variable { personcommunicationlandlines = null; //What to assign here for null json string? string formattedNumber = null; } } Line from listing attached [login to view URL]("@personcommunicationlandlines", personcommunicationlandlines[0].formattedNumber); Full Listing attached Please reply with: The time of day that you are available. I am available 7am to 10pm UTC-06:00 Central Time US & Canada The answer for the question Confidentiality. a) No Use. Recipient agrees not to use the Confidential Information in any way, or to manufacture or test any product embodying Confidential Information, except for the purpose set forth above. b) No Disclosure. Recipient agrees to use its best efforts to prevent and protect the Confidential Information, or any part thereof, from disclosure to any person other than Recipient's employees having a need for disclosure in connection with Recipient's authorized use of the Confidential Information. c) Protection of Secrecy. Recipient agrees to take all steps reasonably necessary to protect the secrecy of the Confidential Information, and to prevent the Confidential Information from falling into the public domain or into the possession of unauthorized persons. d) Scope. The scope of Confidentiality is deemed to be in all contracts present past and future with the Parties to this request.