c# - whats the use of data adapter -

can explain why sqldataadapter used in following code? code working fine without adapter.

also, why use dataadapter? please me understand dataadapter usage.

namespace windowsformsapplication1 {     public partial class form1 : form     {         public form1()         {             initializecomponent();          private void button1_click(object sender, eventargs e)         {             try             {                 sqlconnection con = new sqlconnection("data source=.....\\sqlexpress;initial catalog=......;integrated security=true");                 con.open();                  sqldataadapter da =new sqldataadapter(); // why use `sqldataadapter` here?                 sqlcommand sc = new sqlcommand("insert bhargavc values(" + textbox1.text + "," + textbox2.text + ");", con);                 var o = sc.executenonquery();                 messagebox.show(o + "record inserted");                 con.close();             }             catch (exception)             {                 messagebox.show("error in code");             }         }                private void button2_click(object sender, eventargs e)         {             application.exit();         }          private void form1_load(object sender, eventargs e)         {         }     } } 

there several reasons use dataadapter:

1. you can't fill dataset without one.
2. when adapter completes .fill() method, close connection you; don't have explicitly call .close() method on connection object. although, still practice to.

in case, isn't necessary have 1 though. but, if did want use one, implementation this:

sqldataadapter da = new sqldataadapter();      dataset ds = new dataset(); da.fill(ds); 

from there, there further actions can take on ds object exporting excel via interop, filling datagridview or updating database table.