my gridview footer is not showing the results of calculated columns - asp.net

Question

my aspx code is:
<asp:GridView ID="GridView1" runat="server" AllowPaging="True"
AutoGenerateColumns="False" DataKeyNames="Item_id"
DataSourceID="SqlDataSource2" ShowFooter="True"
onrowdatabound="GridView1_RowDataBound">
<Columns>
<asp:TemplateField HeaderText="Item_id" InsertVisible="False"
SortExpression="Item_id">
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Bind("Item_id") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Bind("Item_id") %>'></asp:Label>
</EditItemTemplate>
<FooterTemplate>
<asp:Button ID="BtnInsert" runat="server" Text="Insert"
Font-Bold="true" BackColor="#0099CC" ForeColor="white" Height="30px" Width="100px" />
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Category_name" SortExpression="Category_name">
<ItemTemplate>
<asp:Label ID="Label2" runat="server" Text='<%# Bind("Category_name") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Category_name") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="TbC" runat="server" Height="20px" Width="120px" Font-Bold="true"></asp:TextBox>
</FooterTemplate>
<ItemStyle Width ="100px" />
</asp:TemplateField>
<asp:TemplateField HeaderText="item_name" SortExpression="item_name">
<ItemTemplate>
<asp:Label ID="Label3" runat="server" Text='<%# Bind("item_name") %>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("item_name") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="TbN" runat="server" Height="20px" Width="120px" Font-Bold="true"></asp:TextBox>
</FooterTemplate>
<ItemStyle Width ="100px" />
</asp:TemplateField>
<asp:TemplateField HeaderText="unit_price" SortExpression="unit_price">
<ItemTemplate>
<asp:TextBox ID="TbPrice" runat="server" Text='<%# Bind("unit_price") %>'></asp:TextBox>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("unit_price") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="TbP" runat="server" Height="20px" Width="100px" Font-Bold="true"></asp:TextBox>
</FooterTemplate>
<ItemStyle Width ="100px" />
</asp:TemplateField>
<asp:TemplateField HeaderText="QuantitySelected"
SortExpression="QuantitySelected">
<ItemTemplate>
<asp:Textbox ID="TbQt" runat="server" Text='<%# Bind("QuantitySelected") %>'></asp:Textbox>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="TextBox4" runat="server"
Text='<%# Bind("QuantitySelected") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="TbQ" runat="server" Height="20px" Width="100px" Font-Bold="true"></asp:TextBox>
</FooterTemplate>
<ItemStyle Width ="100px" />
</asp:TemplateField>
<asp:TemplateField HeaderText="Total" SortExpression="Total">
<ItemTemplate>
<asp:Textbox ID="TbTl" runat="server" Text='<%# Bind("Total") %>'></asp:Textbox>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="TextBox5" runat="server" Text='<%# Bind("Total") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="TbT" runat="server" Height="20px" Width="100px" Font-Bold="true"></asp:TextBox>
</FooterTemplate>
<ItemStyle Width ="100px" />
</asp:TemplateField>
<asp:TemplateField HeaderText="Discount" SortExpression="Discount">
<ItemTemplate>
<asp:Textbox ID="TbD" runat="server" Text='<%# Bind("Discount") %>'></asp:Textbox>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="TextBox6" runat="server" Text='<%# Bind("Discount") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="TbD" runat="server" Height="20px" Width="100px" Font-Bold="true"></asp:TextBox>
</FooterTemplate>
<ItemStyle Width ="100px" />
</asp:TemplateField>
<asp:TemplateField HeaderText="Grand_total" SortExpression="Grand_total">
<ItemTemplate>
<asp:Textbox ID="TbGtl" runat="server" Text='<%# Bind("Grand_total") %>'></asp:Textbox>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="TextBox7" runat="server" Text='<%# Bind("Grand_total") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="TbG" runat="server" Height="20px" Width="100px" Font-Bold="true"></asp:TextBox>
</FooterTemplate>
<ItemStyle Width ="100px" />
</asp:TemplateField>
</Columns>
</asp:GridView>
my code behind is:
public partial class ItemPage : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
protected void btn_Click(object sender, EventArgs e)
{
SqlDataSource2.InsertParameters["Category_name"].DefaultValue = ((TextBox)GridView1.FooterRow.FindControl("TbC")).Text;
SqlDataSource2.InsertParameters["item_name"].DefaultValue = ((TextBox)GridView1.FooterRow.FindControl("TbN")).Text;
SqlDataSource2.InsertParameters["unit_price"].DefaultValue = ((TextBox)GridView1.FooterRow.FindControl("TbP")).Text;
SqlDataSource2.InsertParameters["QuantitySelected"].DefaultValue = ((TextBox)GridView1.FooterRow.FindControl("TbQ")).Text;
SqlDataSource2.InsertParameters["Total"].DefaultValue = ((TextBox)GridView1.FooterRow.FindControl("TbT")).Text;
SqlDataSource2.InsertParameters["Discount"].DefaultValue = ((TextBox)GridView1.FooterRow.FindControl("TbD")).Text;
SqlDataSource2.InsertParameters["Grand_total"].DefaultValue = ((TextBox)GridView1.FooterRow.FindControl("TbG")).Text;
}
double price = 0.0f;
double quantity = 0.0f;
double total = 0.0f;
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
TextBox tb11 = (TextBox)e.Row.FindControl("Tb2");
TextBox tb12 = (TextBox)e.Row.FindControl("Tb3");
TextBox tb13 = (TextBox)e.Row.FindControl("TbPrice");
TextBox tb14 = (TextBox)e.Row.FindControl("TbQt");
TextBox tb15 = (TextBox)e.Row.FindControl("TbTl");
TextBox tb16 = (TextBox)e.Row.FindControl("TbDs");
TextBox tb17 = (TextBox)e.Row.FindControl("TbGtl");
price = Convert.ToDouble(((TextBox)e.Row.FindControl("TbPrice")).Text);
quantity = Convert.ToDouble(((TextBox)e.Row.FindControl("TbQt")).Text);
total = price * quantity;
//total += total;
tb15.Text = total.ToString();
}
else
{
if (e.Row.RowType == DataControlRowType.Footer)
{
TextBox tb1 = (TextBox)e.Row.FindControl("TbC");
TextBox tb2 = (TextBox)e.Row.FindControl("TbN");
TextBox tb3 = (TextBox)e.Row.FindControl("TbP");
TextBox tb4 = (TextBox)e.Row.FindControl("TbQ");
TextBox tb5 = (TextBox)e.Row.FindControl("TbT");
TextBox tb6 = (TextBox)e.Row.FindControl("TbD");
TextBox tb7 = (TextBox)e.Row.FindControl("TbG");
tb5.Text = total.ToString();
}
}
}
}
}
i hv posted my edit code again. the problem is when i run the page i am getting blank textboxes in my footer. only textbox in "total" column has vales and that too is some vague value.. i have to put values in "price" "quantity" and then click "insert" button to add values into grid along with calculated value in "total" column.. i am still stuck!! plz help!!

Answer 1

you also need this:
if (e.Row.RowType == DataControlRowType.DataRow)
where you do the summation.
Note: the variables need to be declared outside the event handler or they will be zeroed on each iteration.
EDIT- zero out the summation variable when e.Row.RowType == DataControlRowType.Header
EDIT Do something like this:
double grand_total = 0;
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.Header)
{
grand_total = 0;
}
if (e.Row.RowType == DataControlRowType.DataRow)
{
double price = Convert.ToDouble(((TextBox)e.Row.FindControl("TbP")).Text);
double quantity = Convert.ToDouble(((TextBox)e.Row.FindControl("TbQ")).Text);
double total = price * quantity ;
((TextBox)e.Row.FindControl("TbT")).Text = total.ToString();
grand_total += total;
}
if (e.Row.RowType == DataControlRowType.Footer)
{
((TextBox)e.Row.FindControl("TbT")).Text = grand_total.ToString() ;
}
}