How to find data key in CheckedChanged checkbox event in ListView in ASP.NET?

Question

I use the list view inside that in the element template I use the label and checkbox. I want that whenever a user clicks on this checkbox, the value should be updated in the table. I am using datakeys in a listview. At the core of the datakey value should be updated in the table. Inquiry:

string updateQuery = "UPDATE [TABLE] SET [COLUMN] = " + Convert.ToInt32(chk.Checked) + " WHERE PK_ID =" + dataKey + " ";` 

I also need help displaying the result, as it is inside the table. If the value for the column in the table for a particular pkid is 1, then the shoul flag will be checked.

Here is the code snippet:

<asp:ListView ID="lvFocusArea" runat="server" DataKeyNames="PK_ID" OnItemDataBound="lvFocusArea_ItemDataBound">
    <LayoutTemplate>
        <table border="0" cellpadding="1" width="400px">
            <tr style="background-color: #E5E5FE">
                <th align="left">
                    Focus Area
                </th>
                <th>
                    Is Current Focused
                </th>
            </tr>
            <tr id="itemPlaceholder" runat="server">
            </tr>
        </table>
    </LayoutTemplate>
    <ItemTemplate>
        <tr>
            <td width="80%">
                <asp:Label ID="lblFocusArea" runat="server" Text=""><%#Eval("FOCUS_AREA_NAME") %></asp:Label>
            </td>
            <td align="center" width="20%">
                <asp:CheckBox ID="chkFocusArea" runat="server" OnCheckedChanged="chkFocusArea_CheckedChanged" AutoPostBack="true" />
            </td>
        </tr>
    </ItemTemplate>
    <AlternatingItemTemplate>
        <tr style="background-color: #EFEFEF">
            <td>
                <asp:Label ID="lblFocusArea" runat="server" Text=""><%#Eval("FOCUS_AREA_NAME") %></asp:Label>
            </td>
            <td align="center">
                <asp:CheckBox ID="chkFocusArea" runat="server" OnCheckedChanged="chkFocusArea_CheckedChanged" AutoPostBack="true" />
            </td>
        </tr>
    </AlternatingItemTemplate>
    <SelectedItemTemplate>
        <td>
            item selected
        </td>
    </SelectedItemTemplate>
</asp:ListView>

Help me.

Answer 1

: datakey

protected void chkFocusArea_CheckedChanged(object sender, EventArgs e)  
{  
    CheckBox cb = (CheckBox)sender;  
    ListViewItem item = (ListViewItem)cb.NamingContainer; 
    ListViewDataItem dataItem = (ListViewDataItem)item ;
    string code = ListView1.DataKeys[dataItem.DisplayIndex].Value.ToString();
}

Answer 2

<asp:CheckBox ID="chkFocusArea" runat="server" Checked='<%# Eval("[COLUMN]")  %>' oncheckedchanged="chkFocusArea_CheckedChanged" AutoPostBack="true" />

chkFocusArea_CheckedChanged .