>>>I'v run into this problem before, and I hit it again tonight:
>>>http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/80ed858a-64e3-4821-a1a3-44940fbf4e83
>>>
>>>How about this for a solution - In my DataAccess class, whenver I receive a DbParameters collection, simply make a local copy of
>>>each parameter, place each copy into a new collection, then assign that collection to the DbCommand object?
>>>
>>>This way, my collection of parameter never really gets used, like this:
>>>
>>>
>>>

>>>private List<DbParameter> _CopyParameters(List<DbParameter> Parameters)
>>>{
>>>    List<DbParameter> RetVal = new List<DbParameter>();
>>>
>>>    foreach (DbParameter Param in Parameters)
>>>    {
>>>        DbParameter NewParam = _Factory.CreateParameter();
>>>        NewParam.ParameterName = Param.ParameterName;
>>>        NewParam.Value = Param.Value;
>>>        NewParam.Direction = Param.Direction;
>>>
>>>        RetVal.Add(NewParam);
>>>
>>>       Parameters.Remove(Param);
>>>
>>>    }
>>>
>>>    return RetVal;
>>>}
>>>

>>>
>>>Then use it like this:
>>>

>>>public int ExecuteNonQuery(string Command, List<DbParameter> Parameters, CommandType CommandType)
>>>{
>>>    int RetVal = 0;
>>>
>>>    DbCommand cmd = _GetCommand(Command);
>>>
>>>    try
>>>    {
>>>        RetVal = cmd.ExecuteNonQuery();
>>>    }
>>>    catch (Exception e)
>>>    {
>>>        throw;
>>>    }
>>>
>>>    return RetVal;
>>>}
>>>

>>>
>>>Then in _GetCommand()...
>>>
>>>

>>>private DbCommand _GetCommand(string Command, List<DbParameter> Parameters, CommandType CmdType)
>>>{
>>>    _GetFactory();
>>>    _GetConnection();
>>>
>>>    DbCommand cmd = _Factory.CreateCommand();
>>>    cmd.CommandText = Command;
>>>    cmd.Connection = _Connection;
>>>    cmd.CommandType = CmdType;
>>>
>>>    if (Parameters != null)
>>>    {
>>>        List<DbParameter> NewParams = _CopyParameters(Parameters);
>>>
>>>        cmd.Parameters.Clear();
>>>        cmd.CommandType = CmdType;
>>>
>>>        foreach (DbParameter p in NewParams)
>>>        {
>>>            cmd.Parameters.Add(p);
>>>        }
>>>    }
>>>
>>>    return cmd;
>>>}
>>>
>>>

>>>
>>>I implemented this and it seems to work. Thoughts?
>>
>>Could you organise things so that the parameter are removed after the command executes - that would mean you wouldn't need a copy everytime:

public int ExecuteNonQuery(List<SqlParameter> l)
>>        {
>>            SqlCommand sc = new SqlCommand();
>>            foreach (SqlParameter p in l){sc.Parameters.Add(p);}
>>            int RetVal = sc.ExecuteNonQuery();
>>            foreach (SqlParameter p in l){sc.Parameters.Remove(p);}
>>            return RetVal;
>>        }

>
>I tried your suggestion. It throws a runtime error "Collection was modified...."

:-{ Oh well, it worked without the actual .ExecuteQuery()

>Oh well. Nice try. Truth is, I'm not unhappy with my workaround.

You still don't really need to make a copy. This should work (with all parameter properties handled):

public int ExecuteNonQuery(List<SqlParameter> l)
        {
            SqlCommand sc = new SqlCommand();

            foreach (SqlParameter p in l)
            {
                sc.Parameters.Add(new SqlParameter(
                    p.ParameterName,
                    p.SqlDbType,
                    p.Size,
                    p.Direction,
                    p.Precision,
                    p.Scale,
                    p.SourceColumn,
                    p.SourceVersion,
                    p.SourceColumnNullMapping,
                    p.Value, p.XmlSchemaCollectionDatabase,
                    p.XmlSchemaCollectionOwningSchema,
                    p.XmlSchemaCollectionName));
            }
            return sc.ExecuteNonQuery();
        }