Writing queries in code behind vs. SqlDataSource

SqlDataAdapter ad = new SqlDataAdapter("SELECT * FROM Categories", myConnection);

DataSet ds = new DataSet();

ad.Fill(ds, "Categories");

myGridView.DataSource = ds;

myGridView.DataBind();

<asp:SqlDataSource ID="SqlDataSource1" runat="server"
  ConnectionString="<%$ ConnectionStrings:myConnection %>"
  SelectCommand="SELECT * FROM Categories" />