nedash says:
if (Ch3D.Checked == true)
            {
                _cmd.Parameters.AddWithValue("@GenrePre", "1");
 
            }
            else
            {
                if (ChOscar.Checked == true)
                {
                    _cmd.Parameters.AddWithValue("@GenrePre", "2");
 
                }
                else {
 
                    if (ChDobleF.Checked == true)
                    {
                        _cmd.Parameters.AddWithValue("@GenrePre", "3");
 
                    }
                }
            }
 Please refer below code.
if (Ch3D.Checked == true)
{
    _cmd.Parameters.AddWithValue("@GenrePre", "1");
}
if (ChOscar.Checked == true)
{                 
    _cmd.Parameters.AddWithValue("@GenrePre", "2");
}
if (ChDobleF.Checked == true)
{                    
     _cmd.Parameters.AddWithValue("@GenrePre", "3");
}