hi am trying to write a code in which i need to perform a update but on primary keys how do i achieve it i have written the following code: kindly look at it let me know where m wrong Protected Sub rgKMSLoc_UpdateCommand(ByVal source As Object, ByVal e As Telerik.Web.UI.GridCommandEventArgs) Handles rgKMSLoc.UpdateCommand Try KAYAReqConn.Open()

        If TypeOf e.Item Is GridEditableItem Then

            Dim strItemID As String = CType(e.Item.FindControl("hdnID"), HiddenField).Value
            Dim strrcmbLocation As String = CType(e.Item.FindControl("rcmbLocation"), RadComboBox).SelectedValue
            Dim strKubeLocation As String = CType(e.Item.FindControl("txtKubeLocation"), TextBox).Text
            Dim strCSVCode As String = CType(e.Item.FindControl("txtCSVCode"), TextBox).Text

            SQLCmd = New SqlCommand("SELECT * FROM MstKMSLocKubeLocMapping WHERE LocationID= '" & rcmbLocation.SelectedValue & "'", KAYAReqConn)

            Dim dr As SqlDataReader
            dr = SQLCmd.ExecuteReader
            If dr.HasRows Then
                lblMsgWarning.Text = "<font color=red>""User ID Already Exists"

                Exit Sub
            End If
            dr.Close()


            SQLCmd = New SqlCommand("UPDATE MstKMSLocKubeLocMapping SET LocationID=@Location,KubeLocation=@KubeLocation,CSVCode=@CSVCode WHERE LocationID = '" & strItemID & "'", KAYAReqConn)
            SQLCmd.Parameters.AddWithValue("@Location", Replace(strrcmbLocation, "'", "''"))
            SQLCmd.Parameters.AddWithValue("@KubeLocation", Replace(strKubeLocation, "'", "''"))
            SQLCmd.Parameters.AddWithValue("@CSVCode", Replace(strCSVCode, "'", "''"))
            SQLCmd.Parameters.AddWithValue("@Status", "A")
            SQLCmd.ExecuteNonQuery()
            lblMessageUpdate.Text = "<font color=blue>""Record Updated SuccessFully"
            SQLCmd.Dispose()
            rgKMSLoc.Rebind()

        End If
    Catch ex As Exception
        Response.Write(ex.ToString)
    Finally
        KAYAReqConn.Close()

    End Try
End Sub

this is my designer page' Location: ' /> ' DataSourceID="dsrcmbLocation" DataTextField="Location" DataValueField="LocationID" Height="150px"> Kube Location: ' Class="forTextBox" MaxLength="4" onkeypress="return filterInput(2,event);"> CSV Code: ' Class="forTextBox" MaxLength="4" onkeypress="return filterInput(2,event);">

                        <tr class="tableRow">
                            <td colspan="2" align="center" class="tableCell">
                                <asp:ImageButton ID="btnUpdate" runat="server" CommandName="Update" CausesValidation="true"
                                    ValidationGroup="Update" ImageUrl="~/Images/update.gif"></asp:ImageButton>
                                <asp:ImageButton ID="btnCancel" runat="server" CausesValidation="false" CommandName="Cancel"
                                    ImageUrl="~/Images/No.gif"></asp:ImageButton>
                            </td>
                        </tr>
                    </table>
                </FormTemplate>
            </EditFormSettings>

Locationid is my primary key