Need to affect Last Enter Value in viewstate in asp.net RSS

Question

my design

 

<table align="center" cellpadding="2" cellspacing="0" border="1" style="width: 900px; height: 100px;border: #04AFEF; background-color: White" id="Tabl">

<tr><td class="style1"><asp:Label ID="SalesNo" runat="server" Text="Sales No"></asp:Label></td>

<td><asp:Label ID="Terms" runat="server" Text="Terms"></asp:Label></td>

<td><asp:Label ID="SalesDate" runat="server" Text="Sales Date"></asp:Label></td>

<td><asp:Label ID="CustomerName" runat="server" Text="Customer Name"></asp:Label></td>

<td class="style3"><asp:Label ID="CounterName" runat="server" Text="CounterName"></asp:Label></td>

<td class="style3"><asp:Label ID="PreviosBillamount" runat="server" Text="Previous Bill Amount"></asp:Label></td></tr>

<tr><td><asp:TextBox ID="txtsalesno" runat="server"></asp:TextBox></td>

<td><asp:TextBox ID="txtTerms" runat="server">Cash</asp:TextBox></td>

<td><asp:TextBox ID="txtSalesDate" runat="server"></asp:TextBox></td>

<td><asp:DropDownList ID="ddCustomerName" runat="server" Height="18px" Width="126px"></asp:DropDownList></td>

<td><asp:DropDownList ID="ddCounterName" runat="server" Height="16px" Width="153px"></asp:DropDownList></td>

<td><asp:TextBox ID="txtPreviosBillamount" runat="server"></asp:TextBox></td></tr>

<tr><td><asp:Label ID="SalesPerson" runat="server" Text="Sales Person"></asp:Label></td>

<td><asp:Label ID="Barcode" runat="server" Text="Barcode"></asp:Label></td>

<td><asp:Label ID="Qty" runat="server" Text="Qty"></asp:Label></td>

<td><asp:Label ID="Rate" runat="server" Text="Rate"></asp:Label></td>

<td><asp:Label ID="Discount" runat="server" Text="Discount %"></asp:Label></td>

<td><asp:Label ID="Discountrs" runat="server" Text="Discount rs"></asp:Label></td></tr>

<tr><td><asp:DropDownList ID="ddSalesPerson" runat="server" Height="17px"

Width="111px"></asp:DropDownList></td>

<td><asp:TextBox ID="txtBarcode" runat="server" AutoPostBack="True" ontextchanged="txtBarcode_TextChanged" onkeypress = "return KeyCode()"></asp:TextBox></td>

<td><asp:TextBox ID="txtqty" runat="server" ontextchanged="txtqty_TextChanged" AutoPostBack="True" onkeypress = "return KeyCode()"></asp:TextBox></td>

<td><asp:TextBox ID="txtrate" runat="server"></asp:TextBox></td>

<td><asp:TextBox ID="txtdispr" runat="server" AutoPostBack="True"

ontextchanged="txtdispr_TextChanged"></asp:TextBox></td>

<td><asp:TextBox ID="txtdisrs" runat="server"></asp:TextBox></td></tr>

<tr><td colspan="6">

<asp:GridView ID="ddsales" runat="server" Width="807px"

AutoGenerateColumns="false" onrowdatabound="ddsales_RowDataBound"

onselectedindexchanged="ddsales_SelectedIndexChanged"

onrowcommand="ddsales_RowCommand" ShowFooter="True"

onrowdeleting="ddsales_RowDeleting"

onselectedindexchanging="ddsales_SelectedIndexChanging"

onprerender="ddsales_PreRender" onrowcreated="ddsales_RowCreated">

<Columns>

<asp:TemplateField ControlStyle-Width="20px">

<ItemTemplate>

<asp:CheckBox ID="chkSelect" runat="server" AutoPostBack="True" oncheckedchanged="chkSelect_CheckedChanged">

</asp:CheckBox>

</ItemTemplate> <ItemStyle Width="20px" />

<ControlStyle Width="20px" />

</asp:TemplateField>

<asp:TemplateField HeaderText="Sectionname" ControlStyle-Width="120px"><ItemTemplate><asp:Label ID="lblsectn" runat="server" Text="<%#bind('sectionname') %>"></asp:Label> </ItemTemplate><ItemStyle Width="120px" VerticalAlign="Bottom" /><ControlStyle Width="120px" /> </asp:TemplateField>

<asp:TemplateField HeaderText="Product Name" ControlStyle-Width="120px"><ItemTemplate><asp:Label ID="lblproductname" runat="server" Text="<%#bind('productname') %>"></asp:Label></ItemTemplate><ItemStyle Width="120px" VerticalAlign="Bottom" /><ControlStyle Width="120px" /></asp:TemplateField>

<asp:TemplateField HeaderText="Lotno" ControlStyle-Width="120px"><ItemTemplate><asp:Label ID="lbllotno" runat="server" Text="<%#bind('lotno') %>"></asp:Label></ItemTemplate><ItemStyle Width="120px" VerticalAlign="Bottom" /><ControlStyle Width="120px" /></asp:TemplateField>

<asp:TemplateField HeaderText="MRP" ControlStyle-Width="120px"><ItemTemplate><asp:Label ID="lblmrp" runat="server" Text="<%#bind('mrp') %>"></asp:Label></ItemTemplate>

<FooterTemplate><asp:Label ID="Salary" runat="server" /></FooterTemplate>

<ItemStyle Width="120px" VerticalAlign="Bottom" /><ControlStyle Width="120px" /></asp:TemplateField>

</Columns>

</asp:GridView>

</td></tr>

<tr><td colspan="4">

<asp:Button ID="btRemove" runat="server" Text="Remove" onclick="btRemove_Click"

Width="170px" />

<asp:Button ID="Button1" runat="server" Text="Clear All" Width="170px"

onclick="Button1_Click" />

</td></tr>

</table>

 

 

 

 

 

my code

 

 

private void BindListView()

{

string constr = ConfigurationManager.AppSettings["s"].ToString();

using (SqlConnection con = new SqlConnection(constr))

{

using (SqlCommand cmd = new SqlCommand())

{

using (SqlDataAdapter sda = new SqlDataAdapter(cmd))

{

cmd.CommandText = "SELECT distinct sectionname,lotno,Productname,mrp from purchasedummy where lotno='" + txtBarcode.Text + "'";

cmd.Connection = con;

//cmd.Parameters.AddWithValue("@PurchaseNo", Convert.ToInt32(this.barcodetx.Text.Trim()));

//cmd.Parameters.AddWithValue("@Qty", Convert.ToInt32(this.qty.Text.Trim()));

DataTable dt = new DataTable();

sda.Fill(dt);

DataTable products = new DataTable();

if (ViewState["Products"] == null)

{

products.Merge(dt, true);

}

else

{

products = (DataTable)ViewState["Products"];

products.Merge(dt, true);

}

ViewState["Products"] = products;

ddsales.DataSource = products;

ddsales.DataBind();

}

}

}

}

 

 

 

protected void txtqty_TextChanged(object sender, EventArgs e)

{

foreach (GridViewRow rowz in ddsales.Rows)

{

double mr, wt, totlrp;

mr =Convert.ToDouble((rowz.FindControl("lblmrp") as Label).Text);

wt = double.Parse(txtqty.Text);

totlrp = mr * wt;

(rowz.FindControl("lblmrp") as Label).Text = Convert.ToString(totlrp);

}

txtqty.Text = "1";

}