Reusing SqlCommand?

Question

I am not really sure if this is possible or not.

I am currently working on a college project and I have a function that uses stored procedures. I would like to know

Answer 1

Yes. You'll want to make sure that you call myCommand.Parameters.Clear between each call in order to dump the parameters, but there's nothing stopping you from reusing the object. (I don't use C# often, so this may have an error or two in the text)

myConStr = ConfigurationManager.ConnectionStrings["MyConnString"].ConnectionString;
myConn = new SqlConnection(myConStr);
myConn.Open();

myCommand = new System.Data.SqlClient.SqlCommand("team5UserCurrentBooks3", myConn); 
myCommand.CommandType = CommandType.StoredProcedure;
myCommand.Parameters.AddWithValue("@book_id", bookID);
myCommand.Parameters.AddWithValue("@user_id", userID);
myCommand.ExecuteNonQuery();

myCommand.Parameters.Clear();
myCommand.CommandText= "NewStoredProcedureName";
myCommand.CommandType = CommandType.StoredProcedure;
myCommand.Parameters.AddWithValue("@foo_id", fooId);
myCommand.Parameters.AddWithValue("@bar_id", barId);
mycommand.ExecuteNonQuery();

myCommand.Parameters.Clear();
myCommand.CommandText = " SELECT * FROM table1 WHERE ID = @TID;"
myCommand.CommandType = CommandType.Text;
myCommand.Parameters.AddWithValue("@tid", tId);
SqlReader rdr;
rdr = myCommand.ExecuteReader();

Answer 2

Yes! You can definitely do that. Within a function you can re-use the same connection as well (I don't recommend re-using a connection object for larger scopes, but it is possible).

You could also do something like this:

myConStr = ConfigurationManager.ConnectionStrings["MyConnString"].ConnectionString;
using (var cn = new SqlConnection(myConStr) )
using (var cmd = new SqlCommand("team5UserCurrentBooks3", cn) ) 
{
    cmd.CommandType = CommandType.StoredProcedure; 
    cmd.Parameters.Add("@user_id", SqlDbType.Int).Value = userID;
    cmd.Parameters.Add("@book_id", SqlDbType.Int);
    cn.Open();

    for(int i = 0; i<10; i++)
    {
        cmd.Parameters["@book_id"].Value = i;
        cmd.ExecuteNonQuery();
    }
}

This will run the query 10 times and use the same user_id each time it executes, but change the book_id. The using block is just like wrapping your connection in a try/catch to make sure it's closed.