how to use sqltransaction in c#

Question

I am using following code to execute two commands at once. I used sqltransaction to assure either all command get executed or rolled back.When I run my program without \"tra

Answer 1

You can create a SqlTransaction from a SqlConnection.

And use it to create any number of SqlCommands

SqlTransaction transaction = connection.BeginTransaction();
var cmd1 = new SqlCommand(command1Text, connection, transaction);
var cmd2 = new SqlCommand(command2Text, connection, transaction);

Or

var cmd1 = new SqlCommand(command1Text, connection, connection.BeginTransaction());
var cmd2 = new SqlCommand(command2Text, connection, cmd1.Transaction);

---

If the failure of commands never cause unexpected changes don't use transaction.

if the failure of commands might cause unexpected changes put them in a Try/Catch block and rollback the operation in another Try/Catch block.

Why another try/catch? According to MSDN:

Try/Catch exception handling should always be used when rolling back a transaction. A Rollback generates an InvalidOperationException if the connection is terminated or if the transaction has already been rolled back on the server.

Here is a sample code:

string connStr = "[connection string]";
string cmdTxt = "[t-sql command text]";

using (var conn = new SqlConnection(connStr))
{
    conn.Open();
    var cmd = new SqlCommand(cmdTxt, conn, conn.BeginTransaction());


    try
    {
        cmd.ExecuteNonQuery();
        //before this line, nothing has happened yet
        cmd.Transaction.Commit();
    }
    catch(System.Exception ex)
    {
        //You should always use a Try/Catch for transaction's rollback
        try
        {
            cmd.Transaction.Rollback();
        }
        catch(System.Exception ex2)
        {
            throw ex2;
        }
        throw ex;
    }

    conn.Close();
}

The transaction is rolled back in the event it is disposed before Commit or Rollback is called.

So you don't need to worry about app being closed.