SqlDataSource.Select Command Not Working?

My compiler says that the line in bold below is illegal. The error msg I'm getting is: No overload for method 'select' takes '0' arguments. How can I correct this error and execute a SELECT?

 protected void Button1_Click(object sender, EventArgs e)

{

SqlDataSource2.Select ();

 }

 protected void SqlDataSource2_Selected(object sender, SqlDataSourceStatusEventArgs e)

{string strReadyFirstName = e.Command.Parameters["@FirstName"].Value.ToString();string strReadyLastName = e.Command.Parameters["@LastName"].Value.ToString();

}

 <asp:SqlDataSource ID="SqlDataSource2" runat="server"

ConnectionString="<%$ ConnectionStrings:ConnectionString %>"

SelectCommand="SELECT [User_ID], [User_Name], [FirstName], [LastName], [Company_Name], [Department_Name] FROM [CompanyDepartment] WHERE ([User_Name] = @User_Name)" OnSelected="SqlDataSource2_Selected">

<selectparameters>

<asp:sessionparameter DefaultValue="TheirUserName" Name="User_Name" SessionField="TheirUserName" Type="String" />

</selectparameters>

</asp:SqlDataSource>