Can not Edit gridview having TemplateField

[coolcoder2007]

Hi,

I have a gridview which is having a TemplateField with a checkbox.When I edit this field an erro is occured saying,"Could not find control 'chkPrimary' in ControlParameter 'Primary_Skill'."I am giving the code below..Plz help me...

<asp:GridView id="gdSkills" runat="server" DataSourceID="SqlDataSource1" DataKeyNames="Emp_code,Skill_Id" PageSize="15" AllowPaging="True" AutoGenerateColumns="False">
<HeaderStyle CssClass="gridViewHeader" />
<RowStyle CssClass="gridViewRowStyle" Wrap="False" Width="100%" />
<AlternatingRowStyle CssClass="gridViewAlternative" Wrap="False" Width="100%" />
<Columns>
<asp:BoundField DataField="Skill_name" HeaderText="Skill" ReadOnly="True" />
<asp:BoundField DataField="No_Months" HeaderText="No of Months" />
<asp:TemplateField HeaderText="Primary">
<ItemTemplate>
<asp:CheckBox ID="chkPrimary" runat="server" Checked='<%# GetBoolean(Eval("Skill_Id"),Eval("Emp_code"))%>' />
</ItemTemplate>
</asp:TemplateField>
<asp:CommandField ShowEditButton= "True"/>
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ProviderName="System.Data.SqlClient"

ConnectionString="<%$ ConnectionStrings:MyDatabase%>"


SelectCommand="select ES.Skill_id,Skill_name,emp_code,No_Months,Primary_ Skill from Skill S
join Emp_skills ES on S.Skill_id=ES.Skill_id
where emp_code=@Emp_code order by Skill_name"
UpdateCommand="update emp_Skills set No_Months=@No_Months,Primary_Skill=@Primary_Skill where Skill_id=@Skill_id AND EMP_CODE=@Emp_Code">
<SelectParameters>
<asp:SessionParameter Name="Emp_code" SessionField="Empcode" Type="String" />
</SelectParameters>
<UpdateParameters>
<asp:Parameter Name="No_Months" Type="Double" />
<asp:Parameter Name="Skill_id" Type="Int32" />
<asp:ControlParameter Name="Primary_Skill" ControlID="chkPrimary" />
<asp:SessionParameter Name="Emp_code" SessionField="Empcode" Type="String" />
</UpdateParameters>
</asp:SqlDataSource>