将DEFAULT值传递到新的SqlParameter（）中

Question

How can i pass DEFAULT value into stored procedure in MVC4 .NET ? I have this code

return Database.SqlQuery<Program>(
                "spGetProgram @p1,@p2,@p3,@p4",
                new SqlParameter("p1", (object)ID ?? "DEFAULT"),
                new SqlParameter("p2", (object)displayStart ?? "DEFAULT"),
                new SqlParameter("p3", (object)displayLength ?? "DEFAULT"),
                new SqlParameter("p4", (object)searchString ?? "DEFAULT")
            ).ToList();

I tried

• "DEFAULT" --> Error: Conversion Failed
• null --> Error: parameter was not passed
• DBNull.Value --> it pass N'' value but this Value is not DEFAULT

How can i do this ?

Answer 1

I found a workaround but it works only for one default parameter.

return Database.SqlQuery<int>(
                "spGetProgramsCount " + (searchString != null ? "@p1" : ""),
                (searchString != null ? new SqlParameter("p1", searchString) : null)
            ).First();

but when I have more parameters for example

return Database.SqlQuery<int>(
                "spGetProgramsCount" + (searchString != null ? " @p1," : "")
+ (searchString2 != null ? " @p2," : "")
+ (searchString3 != null ? " @p3," : ""),
                (searchString != null ? new SqlParameter("p1", searchString) : null), (searchString2 != null ? new SqlParameter("p2", searchString2) : null), (searchString3 != null ? new SqlParameter("p3", searchString3) : null)
            ).First();

I am getting

When executing a command, parameters must be exclusively database parameters or values.

and i believe it is because commas in the procedure, i don't know how to handle it :/