C# 'using' statement question

Question

If you employ a using clause to dispose of a connection, are other items within the clause that implement IDisposable also automatically disposed? If not, how do you handle making sure all IDisposable items are automatically disposed?

public static DataTable ReturnDataTable(
    string ConnectionString, string CommandTextString, CommandType CommandType, 
    int CommandTimeout, List<System.Data.SqlClient.SqlParameter> ParameterList = null)
{
    using (System.Data.SqlClient.SqlConnection Connection =
        new System.Data.SqlClient.SqlConnection())
    {
        Connection.ConnectionString = ConnectionString;

        System.Data.SqlClient.SqlCommand Command =
            new System.Data.SqlClient.SqlCommand();
        Command.Connection = Connection;
        Command.CommandText = CommandTextString;
        Command.CommandType = CommandType;
        Command.CommandTimeout = CommandTimeout;

        if (ParameterList != null)
        {
            if (ParameterList.Count > 0)
            {
                foreach (SqlParameter parameter in ParameterList)
                {
                    Command.Parameters.AddWithValue(
                        parameter.ParameterName, parameter.Value);
                }
            }
        }

        System.Data.DataTable DataTable = new System.Data.DataTable();

        System.Data.SqlClient.SqlDataAdapter DataAdapter =
            new System.Data.SqlClient.SqlDataAdapter();
        DataAdapter.SelectCommand = Command;
        DataAdapter.Fill(DataTable);

        return DataTable;
    }
}

Why don't you use another form of using: using System.Data.SqlClient;? — svick
– svick, Commented Apr 25, 2011 at 2:02

Teoman Soygul · Accepted Answer · 2011-04-25 00:44:45Z

7

You can stack the statements like this (to initialize all disposable objects early on)

using (...)
using (...)
{
  ...
}

or you can use nested using statements for each disposable object you need

using (...)
{
   using (...) { ... }
   using (...) { ... }
}

edited Apr 25, 2011 at 0:44

answered Apr 25, 2011 at 0:35

Teoman Soygul

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KJRB · Accepted Answer · 2011-04-25 00:44:54Z

3

Only an object created in the using clause will be disposed. If you want to make sure that call to dispose is automatically generated for every disposable object created inside of the using block you will need to wrap each of them in a using clause (or you can just call dispose or close, whichever they support, of course). So, the answer is not.

answered Apr 25, 2011 at 0:44

KJRB

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Daniel A. White · Accepted Answer · 2011-04-25 00:35:14Z

2

No. You will have to explicitly call Dispose on the ones that are not inside the parameters of the using statement.

answered Apr 25, 2011 at 0:35

Daniel A. White

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