Because oControl is of type Control, not RadioButton. There's no Checked property to the Control class. You have to cast it:

((RadioButton)oControl).Checked = Convert.ToBoolean(_DataRow[1]);

>Control oControl = null;

>Then later...

>oControl = new MyRadioButton();
>oControl.Text = sCaption;
>oControl.Checked = Convert.ToBoolean(_DataRow[1]);

>I'm getting

>'System.Windows.Forms.Control' does not contain a definition for 'Checked' and no extension method 'Checked' accepting a first argument of type 'System.Windows.Forms.Control' could be found

>Here's MyRadioButton

>class MyRadioButton : RadioButton
>{
>}

>So why isn't the Checked property there?