数据读取器在命令中使用语句

Question

I have a legacy system that I have noticed the following code in

var dataTable = new DataTable();
using(var connection = new SqlConnection())
using(var command = connection.CreateCommand())
{
     command.commandType = CommandType.StoredProcedure;
     //Attach command parameters etc. 
     var reader = command.ExecuteReader();
     dataTable.Load(reader);
}
return dataTable;

Normally I would wrap the data reader into a using statement so the lines would read:

using(var reader = command.ExecuteReader())
{
   dataTable.Load(reader);
}

I think that I'll schedule the time in to update these methods to include a using statement for the data reader as well, but I was wondering whether anyone knew whether, in the instance above, the datareader will get disposed of when the command or connection is disposed of anyway?

Answer 1

You have to do it yourself, since the command doesn't clear up the DataReader for you. See as an example SqlCommand.Dispose .

It is save in this situation to use a using since DataTable.Load doesn't keep a reference to the DataReader used. As a proof of that, see the reference source of DataTable .