I can not edit in the gridview - asp.net

Question

I am using linq to entity i have added the gridview but it's not editing and when i debug it doesn't access the method GridView5_RowUpdating().. here it's the code of the grid view
<asp:GridView ID="GridView5" runat="server" AllowSorting="True"
AutoGenerateColumns="False" CellPadding="4" DataKeyNames="CustomerId"
DataSourceID="SqlDataSource3" ForeColor="#333333" GridLines="None"
onrowupdating="GridView5_RowUpdating">
<AlternatingRowStyle BackColor="White" />
<Columns>
<asp:CommandField ShowDeleteButton="True" ShowEditButton="True" />
<asp:BoundField DataField="CustomerId" HeaderText="CustomerId"
InsertVisible="False" ReadOnly="True" SortExpression="CustomerId" />
<asp:BoundField DataField="FirstName" HeaderText="FirstName"
SortExpression="FirstName" />
<asp:BoundField DataField="LastName" HeaderText="LastName"
SortExpression="LastName" />
<asp:BoundField DataField="City" HeaderText="City" SortExpression="City" />
</Columns>
<FooterStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
<HeaderStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
<PagerStyle BackColor="#FFCC66" ForeColor="#333333" HorizontalAlign="Center" />
<RowStyle BackColor="#FFFBD6" ForeColor="#333333" />
<SelectedRowStyle BackColor="#FFCC66" Font-Bold="True" ForeColor="Navy" />
<SortedAscendingCellStyle BackColor="#FDF5AC" />
<SortedAscendingHeaderStyle BackColor="#4D0000" />
<SortedDescendingCellStyle BackColor="#FCF6C0" />
<SortedDescendingHeaderStyle BackColor="#820000" />
</asp:GridView>
I have Required field validator when i am trying to insert manually when i removed the Required field validator can someone tell me what's happening?

Answer 1

Firstly you need to implement the RowEditing event on the gridview to enable editing, MSDN definition:
Occurs when a row's Edit button is clicked, but before
the GridView control enters edit mode.
ASPX:
<asp:GridView
ID="gvCustomers"
runat="server"
OnRowEditing="gvCustomers_RowEditing">
Code behind:
protected void gvCustomers_RowEditing(object sender, GridViewEditEventArgs e)
{
gvCustomers.EditIndex = e.NewEditIndex;
//Re bind the grid view
}
Now if this event is not being fired when you click the Edit link on your grid view it means that there is some validation logic on the page which is preventing a post back.
The best way to get rid of this issue is to set the ValidationGroup attribute, for the validation controls causing trouble(not the gridview):
<div id="insertEmployee">
<asp:TextBox ID="txtName" runat="server" ValidationGroup="Insert" />
<asp:RequiredFieldValidator ID="rfvName" runat="server" ControlToValidate="txtName" ErrorMessage="Name is required" ValidationGroup="Insert" />
<asp:Button ID="btnAdd" runat="server" Text="Add" ValidationGroup="Insert" />
</div>