Exception while passing enum value to stored procedure using Entity Framework 6

问题

I have an enum

public enum Group
{
        Services = 1,
        Dev = 2,
        Support = 3
}

I am using it in a model

public class Invoice
{
        public int ID { get; set; }
        public DateTime MyDate { get; set; }
        public string Name { get; set; }
        public Group? Group { get; set; }
}

Now I am calling a stored procedure using the above model class:

public ... method(Group grp)
 var Details = this.Context.Database.SqlQuery<Invoice>("spname @ID,@MyDate,@Name,@Group,
 ......
                    new SqlParameter("Group", grp),
                    ).ToList();

Group is of int type in SQL Server.

I get an exception:

Error converting nvarchar to int

in case when there is value in the grp parameter

I get exception when null is there in parameter that enum should be nullable type..but I have made it i,e Group?

The stored procedure itself is working correctly in database using execute command.

回答1:

Try

SqlParameter sqp = null;
if(grp.HasValue)
  sqp=new SqlParameter("Group", grp.Value)
else
  sqp=new SqlParameter("Group", DBNull.Value)
...

Then use sqp in your call to query

Why this complexity? Well.. your grp is type Group? and hence can be null but there isn't a good single line way of converting it to either an int (not nullable) or null (nullable)

回答2:

Change

new SqlParameter("Group", grp)

as

   if(grp.HasValue)
   {
      new SqlParameter("Group", Convert.ToInt32(grp.Value));
   }
   else
   {
     new SqlParameter("Group", DBNull.Value);
   }

should work.

来源：https://stackoverflow.com/questions/45396682/exception-while-passing-enum-value-to-stored-procedure-using-entity-framework-6