I have a gridview populated by checkbox using the code below  
Data Source Result:  
Branch,101,102,103,104,105,106,107,108,109,110  
00001,null,null,null,null,null,null,null,null,null,null  
00016,1,1,1,1,1,0,0,0,0,0
00244,1,1,1,1,1,1,1,1,1,1
 <asp:TemplateField HeaderText="101">
                <ItemTemplate>
                    <asp:CheckBox runat="server" id="cb101" Checked='<%# Eval("101").ToString().Equals("1") %>' />
                </ItemTemplate>
           </asp:TemplateField>... and so on
It is properly working for checkbox if if the column is 0 and 1. 
Now what I need to do is if the column is null the checkbox should be disabled/readonly