Multiplying Two Columns of a gridview and show it in a new column

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i want to mul two columns of my gridview and show it in a third column. The problem i am facing it shows an error of null reference exception in rowdatabound code..how to fix that? This in my .cs code

C#

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Globalization;

public partial class ProjectBilling : System.Web.UI.Page
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["SQLDbConnection"].ConnectionString);
   // SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ProjectManagementConnectionString"].ConnectionString);
    protected void Page_Load(object sender, EventArgs e)
    {
        
        if (!Page.IsPostBack)
        {
            //AppSettingsReader configReader = new AppSettingsReader();

        }

    }

    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) 
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {

            TextBox txtHour = (TextBox)e.Row.FindControl("Hour");
            TextBox txtrate = (TextBox)e.Row.FindControl("RatePerHour");
            TextBox TextBoxInsertTotal = (TextBox)e.Row.FindControl("Total");

            txtHour.Attributes["onKeyup"] = "javascript: return multiplication('" + Convert.ToInt32(txtHour.Text) + "','" + Convert.ToDouble(txtrate.Text) + "','" + Convert.ToInt32(TextBoxInsertTotal.ClientID) + "')";
            txtrate.Attributes["onKeyup"] = "javascript: return multiplication('" + Convert.ToInt32(txtHour.Text) + "','" + Convert.ToDouble(txtrate.Text) + "','" + Convert.ToInt32(TextBoxInsertTotal.ClientID) + "')";
        }
    } 

    private DataSet GetData(string query)
    {
        string conString = ConfigurationManager.ConnectionStrings["SQLDbConnection"].ConnectionString;
        SqlCommand cmd = new SqlCommand(query);
        using (SqlConnection con = new SqlConnection(conString))
        {
            using (SqlDataAdapter sda = new SqlDataAdapter())
            {
                cmd.Connection = con;
                sda.SelectCommand = cmd;
                using (DataSet ds = new DataSet())
                {
                    sda.Fill(ds);
                    return ds;
                }
            }
        }
    }

    protected double CalculateTotal(double RatePerHour, int Hour)
    {
        return RatePerHour * Hour;
    }
    protected void Add_Click(object sender, EventArgs e)
    {
        try
        {

            SqlDataSource1.InsertParameters["Hour"].DefaultValue =
                ((TextBox)GridView1.FooterRow.FindControl("txtHour")).Text;
            SqlDataSource1.InsertParameters["ProjectType"].DefaultValue =
                            ((DropDownList)GridView1.FooterRow.FindControl("ddlName")).SelectedValue;
            SqlDataSource1.InsertParameters["ProjectName"].DefaultValue =
                            ((TextBox)GridView1.FooterRow.FindControl("projectnameTextBox")).Text;
            SqlDataSource1.InsertParameters["Month"].DefaultValue =
                           ((DropDownList)GridView1.FooterRow.FindControl("ddlmonth")).SelectedValue;
            SqlDataSource1.InsertParameters["Year"].DefaultValue =
               ((DropDownList)GridView1.FooterRow.FindControl("ddlyear")).SelectedValue;
            SqlDataSource1.InsertParameters["RatePerHour"].DefaultValue =
               ((TextBox)GridView1.FooterRow.FindControl("txtrate")).Text;


            SqlDataSource1.Insert();
        }
           
        catch (Exception ex)
        {

        }


    }
    
    protected void Button1_Click(object sender, EventArgs e)
    {
        
    }
}

My aspx code is:(total calculation must change after editing the hour or RatePerHour )

XML

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ProjectBilling.aspx.cs" Inherits="ProjectBilling" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Project Billing</title>
    <link href="StyleSheet1.css" rel="stylesheet" />
</head>
<script>
    function multiplication(hour, rate, TextBoxInsertTotal) {
        //Your logic for multiplication
        var hour = document.getElementById(txtHour).value;
        var rate = document.getElementById(txtrate).value;
        document.getElementById(TextBoxInsertTotal).value = hour * rate;
    }
</script>
<body>
    <form id="form1" runat="server">
        <div>
            <div id="menu">
                <ul>
                    <li><a href="HomePage.aspx">Home</a></li>

                    <li><a href="ProjectEntry.aspx">Projects</a></li>

                    <li><a href="ProjectBilling.aspx">Project Billing</a></li>

                    <li><a href="report1.aspx">Report</a></li>

                    <li><a href="login.aspx">Logout</a></li>
                </ul>
            </div>

            <br />
            <br />
            <h2>Project Billing</h2>

            <br />
            <br />

            <asp:GridView ID="GridView1" runat="server" align="center" AutoGenerateColumns="False" CellPadding="4" DataKeyNames="ProjectBillingId" ForeColor="#333333" GridLines="None" ShowFooter="True" DataSourceID="SqlDataSource1" AllowPaging="True" OnRowDataBound="GridView1_RowDataBound">
                <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
                <Columns>
                    <asp:TemplateField HeaderText="" InsertVisible="False" SortExpression="Id">

                        <FooterTemplate>
                            <asp:Button ID="Add" runat="server" Text="Insert" OnClick="Add_Click" />
                        </FooterTemplate>
                    </asp:TemplateField>

                    <asp:TemplateField HeaderText="Project Type" SortExpression="Project Type">
                        <EditItemTemplate>
                            <asp:DropDownList ID="ddlNames" runat="server" DataTextField="ProjectType" DataValueField="ProjectType" DataSourceID="SqlDataSource2" SelectedValue='<%# Bind("ProjectType") %>'>
                            </asp:DropDownList>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:Label ID="Label4" runat="server" Text='<%# Bind("ProjectType") %>'></asp:Label>
                        </ItemTemplate>
                        <FooterTemplate>
                            <asp:DropDownList ID="ddlName" runat="server" DataTextField="ProjectType" DataValueField="ProjectType" DataSourceID="SqlDataSource2">
                            </asp:DropDownList>
                        </FooterTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Project Name" SortExpression="Project Name">
                        <EditItemTemplate>
                            <asp:TextBox ID="projectNameTextBox" runat="server" Text='<%# Bind("ProjectName") %>'>
                            </asp:TextBox>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:Label ID="Label3" runat="server" Text='<%# Bind("ProjectName") %>'></asp:Label>
                        </ItemTemplate>
                        <FooterTemplate>
                            <asp:TextBox ID="projectnameTextBox" runat="server">
                            </asp:TextBox>
                        </FooterTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Hour" SortExpression="Hour">
                        <EditItemTemplate>
                            <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Hour") %>'></asp:TextBox>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:Label ID="Label2" runat="server" Text='<%# Bind("Hour") %>'></asp:Label>
                        </ItemTemplate>
                        <FooterTemplate>
                            <asp:TextBox ID="txtHour" runat="server" CssClass="txthr"></asp:TextBox>
                            <%--<asp:RequiredFieldValidator ID="rfvFirstName" runat="server" ErrorMessage="FirstName is reqired" ControlToValidate="txtFirstName" Text="*" ForeColor="Red"></asp:RequiredFieldValidator>--%>
                        </FooterTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Rate/Hour" SortExpression="Rate/Hour">
                        <EditItemTemplate>
                            <asp:TextBox ID="ratePerHourTextBox" runat="server" Text='<%# Bind("RatePerHour") %>'></asp:TextBox>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:Label ID="hourLabel" runat="server" Text='<%# Bind("RatePerHour") %>'></asp:Label>
                        </ItemTemplate>
                        <FooterTemplate>
                            <asp:TextBox ID="txtrate" runat="server" ></asp:TextBox>
                            <%--<asp:RequiredFieldValidator ID="rfvFirstName" runat="server" ErrorMessage="FirstName is reqired" ControlToValidate="txtFirstName" Text="*" ForeColor="Red"></asp:RequiredFieldValidator>--%>
                        </FooterTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Total" SortExpression="Total">
                        <%--<ItemTemplate>
                            <asp:Label ID="totalLabel" runat="server" CssClass="total" Text='<%#DataBinder.Eval(Container.DataItem,("RatePerHour"))%>*<%#DataBinder.Eval(Container.DataItem,("Hour"))%>'></asp:Label>
                        </ItemTemplate>--%>
                        <%--<EditItemTemplate>
                            <asp:TextBox ID="TextBoxEditTotal" runat="server" Text='<%#CalculateTotal((double)Eval("RatePerHour"), (int)Eval("Hour")) %>'></asp:TextBox>
                        </EditItemTemplate>--%>
                         <FooterTemplate>
                            <asp:TextBox ID="TextBoxInsertTotal" runat="server" ></asp:TextBox>
                        </FooterTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Year" SortExpression="Year">
                        <EditItemTemplate>
                            <asp:DropDownList ID="DropDownList3" runat="server" SelectedValue='<%# Bind("Year") %>'>
                                <asp:ListItem Value="-1">Year:</asp:ListItem>
                                <asp:ListItem Value="2017">2017</asp:ListItem>
                                <asp:ListItem Value="2016">2016</asp:ListItem>
                                <asp:ListItem Value="2015">2015</asp:ListItem>
                                <asp:ListItem Value="2014">2014</asp:ListItem>
                                <asp:ListItem Value="2013">2013</asp:ListItem>
                                <asp:ListItem Value="2012">2012</asp:ListItem>
                                <asp:ListItem Value="2011">2011</asp:ListItem>
                                <asp:ListItem Value="2010">2010</asp:ListItem>
                                <asp:ListItem Value="2009">2009</asp:ListItem>

                            </asp:DropDownList>
                            <%--<asp:RequiredFieldValidator ID="rfvEditYear" runat="server" ErrorMessage="Year is reqired" ControlToValidate="DropDownList3" Text="*" ForeColor="Red" InitialValue="Year:"></asp:RequiredFieldValidator>--%>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:Label ID="Label9" runat="server" Text='<%# Bind("Year") %>'></asp:Label>
                        </ItemTemplate>
                        <FooterTemplate>
                            <asp:DropDownList ID="ddlyear" runat="server">
                                <asp:ListItem Value="-1">Year:</asp:ListItem>
                                <asp:ListItem Value="2017">2017</asp:ListItem>
                                <asp:ListItem Value="2016">2016</asp:ListItem>
                                <asp:ListItem Value="2015">2015</asp:ListItem>
                                <asp:ListItem Value="2014">2014</asp:ListItem>
                                <asp:ListItem Value="2013">2013</asp:ListItem>
                                <asp:ListItem Value="2012">2012</asp:ListItem>
                                <asp:ListItem Value="2011">2011</asp:ListItem>
                                <asp:ListItem Value="2010">2010</asp:ListItem>
                                <asp:ListItem Value="2009">2009</asp:ListItem>

                            </asp:DropDownList>
                            <%--<asp:RequiredFieldValidator ID="rfvYear" runat="server" ErrorMessage="Year is reqired" ControlToValidate="ddlyear" Text="*" ForeColor="Red" InitialValue="Day:"></asp:RequiredFieldValidator>--%>
                        </FooterTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Month" SortExpression="Month">
                        <EditItemTemplate>
                            <asp:DropDownList ID="DropDownList2" runat="server" SelectedValue='<%# Bind("Month") %>'>
                                <asp:ListItem Value="-1">Month:</asp:ListItem>
                                <asp:ListItem Value="January">January</asp:ListItem>
                                <asp:ListItem Value="February">February</asp:ListItem>
                                <asp:ListItem Value="March">March</asp:ListItem>
                                <asp:ListItem Value="April">April</asp:ListItem>
                                <asp:ListItem Value="May">May</asp:ListItem>
                                <asp:ListItem Value="June">June</asp:ListItem>
                                <asp:ListItem Value="July">July</asp:ListItem>
                                <asp:ListItem Value="August">August</asp:ListItem>
                                <asp:ListItem Value="September">September</asp:ListItem>
                                <asp:ListItem Value="October">October</asp:ListItem>
                                <asp:ListItem Value="November">November</asp:ListItem>
                                <asp:ListItem Value="December">December</asp:ListItem>
                            </asp:DropDownList>
                            <%--<asp:RequiredFieldValidator ID="rfvEditMonth" runat="server" ErrorMessage="Month is reqired" ControlToValidate="DropDownList2" Text="*" ForeColor="Red" InitialValue="Month:"></asp:RequiredFieldValidator>--%>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:Label ID="Label8" runat="server" Text='<%# Bind("Month") %>'></asp:Label>
                        </ItemTemplate>
                        <FooterTemplate>
                            <asp:DropDownList ID="ddlmonth" runat="server">
                                <asp:ListItem Value="-1">Month:</asp:ListItem>
                                <asp:ListItem Value="January">January</asp:ListItem>
                                <asp:ListItem Value="February">February</asp:ListItem>
                                <asp:ListItem Value="March">March</asp:ListItem>
                                <asp:ListItem Value="April">April</asp:ListItem>
                                <asp:ListItem Value="May">May</asp:ListItem>
                                <asp:ListItem Value="June">June</asp:ListItem>
                                <asp:ListItem Value="July">July</asp:ListItem>
                                <asp:ListItem Value="August">August</asp:ListItem>
                                <asp:ListItem Value="September">September</asp:ListItem>
                                <asp:ListItem Value="October">October</asp:ListItem>
                                <asp:ListItem Value="November">November</asp:ListItem>
                                <asp:ListItem Value="December">December</asp:ListItem>
                            </asp:DropDownList>
                            <%--<asp:RequiredFieldValidator ID="rfvMonth" runat="server" ErrorMessage="Month is reqired" ControlToValidate="ddlmonth" Text="*" ForeColor="Red" InitialValue="Month:"></asp:RequiredFieldValidator>--%>
                        </FooterTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField ShowHeader="False">
                        <EditItemTemplate>
                            <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="True" CommandName="Update" Text="Update"></asp:LinkButton>
                            &nbsp;<asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel"></asp:LinkButton>
                        </EditItemTemplate>
                        <ItemTemplate>
                            <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" CommandName="Edit" Text="Edit"></asp:LinkButton>
                            &nbsp;<asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" CommandName="Delete" Text="Delete"></asp:LinkButton>
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>
                <EditRowStyle BackColor="#999999" />
                <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
                <RowStyle BackColor="#F7F6F3" ForeColor="#333333" HorizontalAlign="Center" />
                <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
                <SortedAscendingCellStyle BackColor="#E9E7E2" />
                <SortedAscendingHeaderStyle BackColor="#506C8C" />
                <SortedDescendingCellStyle BackColor="#FFFDF8" />
                <SortedDescendingHeaderStyle BackColor="#6F8DAE" />
            </asp:GridView>
            <asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ConnectionStrings:ProjectManagementConnectionString%>" SelectCommand="SELECT * from Project"></asp:SqlDataSource>
            <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ProjectManagementConnectionString %>" DeleteCommand="DELETE FROM [ProjectBilling] WHERE [ProjectBillingId] = @ProjectBillingId" InsertCommand="INSERT INTO [ProjectBilling] ([Hour],[RatePerHour], [ProjectType],[ProjectName], [Month], [Year]) VALUES (@Hour,@RatePerHour, @ProjectType,@ProjectName, @Month, @Year)" SelectCommand="SELECT * FROM [ProjectBilling]" UpdateCommand="UPDATE [ProjectBilling] SET [Hour] = @Hour,[RatePerHour]=@RatePerHour, [ProjectType] = @ProjectType,[ProjectName] = @ProjectName, [Month] = @Month, [Year] = @Year WHERE [ProjectBillingId] = @ProjectBillingId">
                <DeleteParameters>
                    <asp:Parameter Name="ProjectBillingId" Type="Int32" />
                </DeleteParameters>
                <InsertParameters>
                    <asp:Parameter Name="Hour" Type="String" />
                    <asp:Parameter Name="RatePerHour" Type="Double" />
                    <asp:Parameter Name="ProjectType" Type="String" />
                    <asp:Parameter Name="ProjectName" Type="String" />
                    <asp:Parameter Name="Month" Type="String" />
                    <asp:Parameter Name="Year" Type="String" />
                </InsertParameters>
                <UpdateParameters>
                    <asp:Parameter Name="Hour" Type="String" />
                    <asp:Parameter Name="RatePerHour" Type="Double" />
                    <asp:Parameter Name="ProjectType" Type="String" />
                    <asp:Parameter Name="ProjectName" Type="String" />
                    <asp:Parameter Name="Month" Type="String" />
                    <asp:Parameter Name="Year" Type="String" />
                    <asp:Parameter Name="ProjectBillingId" Type="Int32" />
                </UpdateParameters>
            </asp:SqlDataSource>
            <br />

        </div>
    </form>
</body>
</html>

Posted 10-Mar-15 22:53pm

star_tasneem

Updated 10-Mar-15 22:56pm

v3

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