Creating and using objects in C#

Question

Hi everyone There are two ways by which we can use objects in C#. 1) DataSet ds = new DataSet(); 2) DataSet ds; Can anyone tell me what is the difference between these two. I know logically in the first one memory is allocated for that object and constructors are called. But we are used to with both the ways of creating the objects. Which is the correct way to create object and what are the situations on which either of the two should be used. Its very helpful if example is given with explanation. Thanks Pankaj

Pankaj Sahasrabudhe · Answer

Thanks for the reply that cleared my doubt. :)

Scott Lysle · Answer

DataSet ds = new DataSet(); creates a new instance of the dataset. DataSet ds; declares the variable but it is unassigned (no new instance exists yet) private void button1_Click( object sender EventArgs e) { DataSet ds; // Throws an error here ds.DataSetName = Chuck ; DataTable dt = new DataTable (); ds.Tables.Add(dt); } private void button2_Click( object sender EventArgs e) { DataSet ds = new DataSet (); // allows this since the dataset exists here ds.DataSetName = Chuck ; DataTable dt = new DataTable (); ds.Tables.Add(dt); }