c# - How to set DateTime object to null and sent as parameter to stored procedure? -

i call stored procedure visual studio project , passing datetime parameter.

here c# code:

datetime? dtstartfrom = null; var result = _context.database.sqlquery<damageeventsdtl>("spdamageeventsdtl  @dtstartfrom", new sqlparameter("dtstartfrom", dtstartfrom)).tolist(); 

here how variable defined in stored procedure:

@dtstartfrom date 

on row exception:

the parameterized query '(@dtstartfrom nvarchar(4000))spdamageeventsdtl  @dtstartfrom' expects parameter '@dtstartfrom', not supplied. 

so guess there problem null values, tryed way:

 datetime? dtstartfrom = dbnull.value; 

but on row above error:

cannot implicitly convert type 'system.dbnull' 'system.datetime?' 

any idea how can set datetime object null , sent parameter stored procedure?

your parameter name should match of query:

new sqlparameter("@dtstartfrom", dtstartfrom); 

edit:

datetime? dtstartfrom = null; sqlparameter sqldateparam = new sqlparameter("@dtstartfrom", sqldbtype.datetime); sqldateparam.isnullable = true;  if (dtstartfrom.hasvalue)     sqldateparam.value = dtstartfrom.value; else     sqldateparam.value = dbnull.value  var result = _context.database.sqlquery<damageeventsdtl>("spdamageeventsdtl  @dtstartfrom", sqldateparam).tolist();