Ajax toolkit error - Uncaught Sys.WebForms.PageRequestManagerServerErrorException: Sys.WebForms.PageRequestManagerServerErrorException: Input string was not in a correct format.

 Uncaught Sys.WebForms.PageRequestManagerServerErrorException: Sys.WebForms.PageRequestManagerServerErrorException: Input string was not in a correct format.

If you get the above error, please add command argument in link button of grid

 <asp:TemplateField HeaderText="Modify" Visible="true">

                <ItemTemplate>

                    <asp:LinkButton ID="lnkModify" runat="server" CssClass="btn btn-danger" CommandName="Modify"

                        ToolTip="modify"  CommandArgument='<%# Eval("ID")%>' > Modify</asp:LinkButton>

                </ItemTemplate>

            </asp:TemplateField>