How to avoid multiple times calling a method

Hi all,
I have an checkboxlist control i need to avoid to calling a method redundantly...Please check my code

Page Design:

<asp:CheckBoxList ID="chkContactDetails" runat="server" 
        RepeatDirection="Horizontal" AutoPostBack="True" 
        onselectedindexchanged="chkContactDetails_SelectedIndexChanged">
<asp:ListItem>Contact Details</asp:ListItem>
<asp:ListItem>Horoscope Details</asp:ListItem>
<asp:ListItem>Kundali Details</asp:ListItem>
</asp:CheckBoxList>

Code.cs file

checkboxlist_selection changed EVENT

for (int i = 0; i < chkContactDetails.Items.Count; i++)
            {
                if (chkContactDetails.Items[i].Selected == true)
                {
                    if (chkContactDetails.Items[i].Text == "Contact Details")
                    {
                        tblContactDetails.Visible = true;
                        GetContactDetails(CustId);                       
                    }
                    else if (chkContactDetails.Items[i].Text == "Horoscope Details")
                    {
                        tblHoroscopeDetails.Visible = true;
                        GetHoroscopeDetails(CustId);                       
                    }
                    else if (chkContactDetails.Items[i].Text == "Kundali Details")
                    {
                        GetKundaliDetails(CustId);
                    }
                }
}

when ever i am selecting the last check box kundali details and then i am selecting and deselecting the other two check boxes at every time it was getting to database and once again calling the function how to avoid this. I need to call the method only once after selection of a specific item..

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