sql - How do I "select null as "Column" Using LINQ in C# -

How can I select tap in LINQ as a column option?

My SQL will be read.

  Select field 1, field 2, field 3, tap in the form of "faucet", field 4 will be field 4   
 my Linux query:  
  Select from table 1 new {t.field1, t.field2, t.field3, null as "null", t.field4}   
 There is an error generated by Visual Studio:  
 
 Anonymous type property can not be assigned    
 
 
 Drop  as" zero " and parameter name,  null  Casting in:  
  Select the new one from the new {t.field1, T.field2, t.field3, someField = (string) null, t.field4}  < / Pre>