ADO.Net

Vikram Agrawal

Why we can not create the object of DataReader class?

3 Replies

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Jignesh Trivedi12y ago
hi,

The SqlCommand.ExecuteReader() method returns an instance of the SqlDataReader class.data rows would be assigned to the cmd.ExecuteReader and it's previous assignment to an empty SqlReader would be pointless. Furthermore, the cmd.ExecuteReader() works as a factory method creating the SqlDataReader instance. we can't go about using the new keywords as SqlDataReader and also doesn't have a public constructor defined for SqlReader class.

hope this will help you.
Vikram Agrawal12y ago
well
when we create the object of SqlDataReader then its shows an compile time error that SqlDataReader class doesnt have any constructor in it.

and when we go to the meta data file of SqlDataReader there is no constructor presents in it.
Vulpes12y ago
Well, all data readers in the .NET framework inherit from the abstract DbDataReader class and you can't create an object of an abstract class in C#.

However, you can create objects of the 'concrete' data readers such as SqlDataReader or OdbcDataReader even though they don't have constructors.

To create an object, you have to call the ExecuteReader() method of the associated Command object instead. It's done like this because a data reader needs exclusive access to the corresponding connection and so they don't want you to be creating more than one data reader at a time.