Try this code and let me know the result.
private void rdodate_CheckedChanged(object sender, EventArgs e)
{
if (rdodate.Checked)
{
dateTimePicker1.Enabled = true;
ddmonth_fee_report.Enabled = false;
}
}
private void rdomonth_CheckedChanged(object sender, EventArgs e)
{
if (rdomonth.Checked)
{
ddmonth_fee_report.Enabled = true;
dateTimePicker1.Enabled = false;
}
}