Set the Enabled property of a Checkbox

Hello,
I have a checkbox in my aspx and a public boolean in the code behind.
Now i want to set the enabled property of the checkbox using the variable. I have tried the following but couldn't get it to work.
<asp:CheckBox ID="cbCheckAll1" runat="server" Enabled='<%=LockStatus %>'/>

If you have any other work around that might help.. please let me know.. Any help will be greatly appreciated.
P.S.: I must do it this way.. i cannot do it like cb.CheckAll1.enabled = LockStatus
Thank you
--Pavan

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