>>>>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();
>        }

This is essentially doing the same thing. For each param, create a new one with the same prop values, and assign it to the cmd. The
only drawback in my case is that I'm using a factory and not all of the Param properties are supported. The technique I used doesn't
care about that.