Update row in Gridview? - c#-4.0

Question

I have updated a row in Gridview but it is not working.
Here is my code :
protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex];
//Label lbldeleteid = (Label)row.FindControl("Label1");
string bname= GridView1.DataKeys[e.RowIndex].Values["manufacturer"].ToString();
TextBox tbmanu = (TextBox)GridView1.Rows[e.RowIndex].Cells[0].Controls[1];
var myString = tbmanu.ToString();
SqlCommand cmd = new SqlCommand("manu_upd",con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add("#manufacturer", SqlDbType.NVarChar,100);
cmd.Parameters["#manufacturer"].Value = myString;
con.Open();
cmd.ExecuteNonQuery();
con.Close();
GridView1.EditIndex = -1;
BindData();
I got the following error :
Unable to cast object of type 'System.Web.UI.LiteralControl' to type
'System.Web.UI.WebControls.TextBox'.
here is my Grid view :
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
CellPadding="4" DataKeyNames="manufacturer" ForeColor="#333333"
GridLines="None" Width="400px" BorderStyle="Double"
CellSpacing="3" Font-Bold="True" Font-Size="Small" ShowFooter="True"
ShowHeaderWhenEmpty="True" onrowdeleting="GridView1_RowDeleting"
onrowediting="GridView1_RowEditing"
onrowupdating="GridView1_RowUpdating"
onrowcancelingedit="GridView1_RowCancelingEdit"
AutoGenerateEditButton="True">
<AlternatingRowStyle BackColor="White"/>
<Columns>
<asp:TemplateField HeaderText="Number" ItemStyle-
HorizontalAlign="Center">
<ItemTemplate>
<asp:Label ID="lbnaumber" runat="server" Text='<%#
Container.DataItemIndex + 1 %>'></asp:Label>
</ItemTemplate>
<ItemStyle HorizontalAlign="Center"></ItemStyle>
</asp:TemplateField>
<asp:TemplateField HeaderText="Manufacturer"
SortExpression="manufacturer">
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%#
Bind("manufacturer") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="tbmanu" runat="server" Text='<%#
Bind("manufacturer") %>'></asp:TextBox>
</EditItemTemplate>
<ItemStyle HorizontalAlign="Center" />
</asp:TemplateField>
<%--<asp:CommandField ShowEditButton="True" />--%>
<asp:CommandField ShowDeleteButton="True" />
</Columns>
<EditRowStyle BackColor="#2461BF"/><FooterStyle BackColor="#507CD1"
Font-Bold="True" ForeColor="White" />
<HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White"/>
<PagerStyle BackColor="#2461BF" ForeColor="White"
HorizontalAlign="Center" />
<RowStyle BackColor="#EFF3FB" /><SelectedRowStyle BackColor="#D1DDF1"
Font-Bold="True" ForeColor="#333333" />
<SortedAscendingCellStyle BackColor="#F5F7FB"/>
<SortedAscendingHeaderStyle BackColor="#6D95E1" />
<SortedDescendingCellStyle BackColor="#E9EBEF" />
<SortedDescendingHeaderStyle BackColor="#4870BE" />
</asp:GridView>
When I change the index of my text box 1 to 3 it shows me below error :
Specified argument was out of the range of valid values.
Parameter name: index
When i change its index 3 to 2 it gives me below error :
Unable to cast object of type 'System.Web.UI.WebControls.DataControlLinkButton' to type 'System.Web.UI.WebControls.TextBox'.
I have one required field validator in my form but when I enable that validation update in grid view is not working.

Answer 1

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
GridViewRow row = GridView1.Rows[e.RowIndex];
TextBox tbmanu1 = (TextBox)row.FindControl("tbmanu");
//or try
//TextBox tbmanu1= (TextBox)row.Cells[0].FindControl("tbmanu");
string myString = Convert.Tostring(tbmanu1.text);
cmd.Parameters["#manufacturer"].Value = myString;
}

Answer 2

Try wrapping your gridview in a asp:UpdatePanel and set the update mode to conditional.
Good Luck