>>>>>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.

My point was that you don't need to make a copy of the whole list. Just using the existing one to feed in the new parameters is more efficient.
NBD .....