Object reference not set to an instance of an object. in gridview on RowDataCommand

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Dear Friend I have one Gridview with the name Geidview1 when we calculate running total of column values on RowDataCommand Event it return an error "Object reference not set to an instance of an object"
below is the image of error

please any one can suggest us how we can remove this error.

below is my code

my c# code for bind gridview

public void bindgvduedate()
{
con = new SqlConnection();
con.ConnectionString = ConfigurationManager.ConnectionStrings["con1"].ConnectionString;
con.Open();
SqlCommand cmd = new SqlCommand();
cmd.CommandText = "readfeedetails";
cmd.CommandType = CommandType.StoredProcedure;
cmd.Connection = con;
////cmd.Parameters.AddWithValue("@classname",Convert.ToString(ddlclassname.SelectedItem));
////cmd.Parameters.AddWithValue("@feecatename", Convert.ToString(ddlstcategory.SelectedItem));

SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable table = new DataTable();
da.Fill(table );
GridView1.DataSource= table;
GridView1.DataBind();
con.Close();

}

this function i call on page load event

Griedview aspx code

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
BackColor="White" BorderColor="#336666" BorderStyle="Double"
Font-Size="11px" BorderWidth="3px"
CellPadding="4" GridLines="both"
ShowFooter="True" onrowdatabound="GridView1_RowDataBound">
<rowstyle forecolor="#333333" backcolor="White" height="21px">
<columns>
<asp:TemplateField>
<HeaderTemplate>Apr-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lblaprl" runat="server" Text='<%#Eval("Apr-15") %>'>
<footertemplate> <asp:Label ID="lbl_aprTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>May-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lblmay" runat="server" Text='<%#Eval("May-15")%>'>
<footertemplate> <asp:Label ID="lbl_mayTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Jun-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lbljun" runat="server" Text='<%#Eval("Jun-15") %>'>
<footertemplate> <asp:Label ID="lbl_junTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Jul-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lbljul" runat="server" Text='<%#Eval("Jul-15") %>'>
<footertemplate> <asp:Label ID="lbl_julTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Aug-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lblaug" runat="server" Text='<%#Eval("Aug-15") %>'>
<footertemplate> <asp:Label ID="lbl_augTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Sep-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lblsep" runat="server" Text='<%#Eval("Sep-15") %>'>
<footertemplate> <asp:Label ID="lbl_sepTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Oct-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lbloct" runat="server" Text='<%#Eval("Oct-15") %>'>
<footertemplate> <asp:Label ID="lbl_octTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Nov-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lblnov" runat="server" Text='<%#Eval("Nov-15") %>'>
<footertemplate> <asp:Label ID="lbl_novTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Dec-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lbldec" runat="server" Text='<%#Eval("Dec-15") %>'>
<footertemplate> <asp:Label ID="lbl_decTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Jan-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lbljan" runat="server" Text='<%#Eval("Jan-15") %>'>
<footertemplate> <asp:Label ID="lbl_janTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Feb-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lblfeb" runat="server" Text='<%#Eval("Feb-15") %>'>
<footertemplate> <asp:Label ID="lbl_febTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Mar-15 </HeaderTemplate>
<itemtemplate><asp:Label ID="lblmar" runat="server" Text='<%#Eval("Mar-15") %>'>
<footertemplate> <asp:Label ID="lbl_marTotalamount" CssClass="footer_text" runat="server" Text="1">

<asp:TemplateField>
<HeaderTemplate>Total </HeaderTemplate>
<itemtemplate><asp:Label ID="lbltotal" runat="server" Text="0">
<footertemplate> <asp:Label ID="lbl_Totalsamount" CssClass="footer_text" runat="server" Text="1">

<footerstyle backcolor="White" forecolor="#333333">
<pagerstyle backcolor="#336666" forecolor="White" horizontalalign="Center">
<SelectedRowStyle BackColor="#339966" Font-Bold="True" ForeColor="White" />
<HeaderStyle BackColor="#336666" Font-Bold="True" ForeColor="White" />

code for calculating running total

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{

if (e.Row.RowType == DataControlRowType.Footer)
{
con = new SqlConnection();
con.ConnectionString = ConfigurationManager.ConnectionStrings["con1"].ConnectionString;
con.Open();
SqlCommand cmd = new SqlCommand("select sum(feeamount) from dbo.feemaster where classname='KG'and feeactive=1 and feecatename='NEW'and duemonth='Apr-15'", con);
SqlDataReader dr = cmd.ExecuteReader();
if (dr.Read())
{
//e.Row.Cells[1].Text = "Total : ";
Label lbl_aprTotalamount = GridView1.FindControl("lbl_aprTotalamount") as Label;
lbl_aprTotalamount.Text = dr[0].ToString();
}

}

}

my database table

CREATE TABLE [dbo].[feemaster](
[feeId] [int] IDENTITY(1,1) NOT NULL,
[feetype] [nvarchar](50) NULL,
[feename] [nvarchar](50) NULL,
[classname] [nvarchar](50) NULL,
[duemonth] [nvarchar](50) NULL,
[feeamount] [decimal](15, 2) NULL,
[feeactive] [bit] NULL,
[feecatename] [nvarchar](50) NULL
) ON [PRIMARY]
GO
SET IDENTITY_INSERT [dbo].[feemaster] ON
INSERT [dbo].[feemaster] ([feeId], [feetype], [feename], [classname], [duemonth], [feeamount], [feeactive], [feecatename]) VALUES (1, N'One Time', N'Prospectus & Registration Fee', N'PRE NURSURY', N'Apr-15', CAST(300.00 AS Decimal(15, 2)), 1, N'NEW')
INSERT [dbo].[feemaster] ([feeId], [feetype], [feename], [classname], [duemonth], [feeamount], [feeactive], [feecatename]) VALUES (13, N'One Time', N'Prospectus & Registration Fee', N'NURSURY', N'Apr-15', CAST(300.00 AS Decimal(15, 2)), 1, N'NEW')
INSERT [dbo].[feemaster] ([feeId], [feetype], [feename], [classname], [duemonth], [feeamount], [feeactive], [feecatename]) VALUES (2, N'One Time', N'Prospectus & Registration Fee', N'KG', N'Apr-15', CAST(300.00 AS Decimal(15, 2)), 1, N'NEW')

INSERT [dbo].[feemaster] ([feeId], [feetype], [feename], [classname], [duemonth], [feeamount], [feeactive], [feecatename]) VALUES (16, N'Annual', N'Maintenance Fee', N'NURSURY', N'Apr-15', CAST(500.00 AS Decimal(15, 2)), 1, N'NEW')
INSERT [dbo].[feemaster] ([feeId], [feetype], [feename], [classname], [duemonth], [feeamount], [feeactive], [feecatename]) VALUES (17, N'Annual', N'Maintenance Fee', N'NURSURY', N'Apr-15', CAST(500.00 AS Decimal(15, 2)), 1, N'OLD')
INSERT [dbo].[feemaster] ([feeId], [feetype], [feename], [classname], [duemonth], [feeamount], [feeactive], [feecatename]) VALUES (18, N'Annual', N'Maintenance Fee', N'KG', N'Apr-15', CAST(500.00 AS Decimal(15, 2)), 1, N'NEW')

my stored procedure

create proc [dbo].[readfeedetails]
AS
BEGIN
select
*
from
(
select f.feename, f.feeamount,dd.duemonth
from feemaster as f
left outer join duedate as dd on dd.duemonth =f.duemonth where classname='KG' and feeactive=1 and feecatename='OLD'

) as f
pivot
(
min(f.feeamount)
for f.duemonth in ([Apr-15],[May-15],[Jun-15],[Jul-15],[Aug-15],[Sep- 15],[Oct-15],[Nov-15],[Dec-15],[Jan-15],[Feb-15],[Mar-15])
) as PIV

END

GO

Posted 23-Nov-15 23:18pm

jitendra raj

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Comments

Raje_ 24-Nov-15 5:30am

Did you trying debugging? In Which line you get this error?
My guess is in this line "ConfigurationManager.ConnectionStrings["con1"].ConnectionString;". Have you declared a connection string in web.config file with name 'con1'?

jitendra raj 24-Nov-15 5:42am

Thanks raj for you reply, yes I Have declared a connection string in web.config file with name 'con1'?

and we found error here

Line 191: lbl_aprTotalamount.Text = dr[0].ToString();

Raje_ 24-Nov-15 6:13am

Cool. And please check Solution 1. He has given a very nice example.

F-ES Sitecore 24-Nov-15 6:21am

So examine that line in the debugger, what is null? lbl_aprTotaslamount? If so how are you populating that variable? It's in the line above so your FindControl is returning null. Google "RowDataBound findcontrol" and look at the examples that show how you use FindControl in the RowDataBound event and there is the answer to your problem.

If you learn to debug your code then you get the solutions to your problems much faster and you become a better developer. Dumping hundreds of lines of code onto a form and asking people what the problem is without even saying basic info like the line that throws the error helps no-one.

3 solutions

Solution 1

This is one of the most common problems we get asked, and it's also the one we are least equipped to answer, but you are most equipped to answer yourself.

Let me just explain what the error means: You have tried to use a variable, property, or a method return value but it contains null - which means that there is no instance of a class in the variable.
It's a bit like a pocket: you have a pocket in your shirt, which you use to hold a pen. If you reach into the pocket and find there isn't a pen there, you can't sign your name on a piece of paper - and you will get very funny looks if you try! The empty pocket is giving you a null value (no pen here!) so you can't do anything that you would normally do once you retrieved your pen. Why is it empty? That's the question - it may be that you forgot to pick up your pen when you left the house this morning, or possibly you left the pen in the pocket of yesterdays shirt when you took it off last night.

We can't tell, because we weren't there, and even more importantly, we can't even see your shirt, much less what is in the pocket!

Back to computers, and you have done the same thing, somehow - and we can't see your code, much less run it and find out what contains null when it shouldn't.
But you can - and Visual Studio will help you here. Run your program in the debugger and when it fails, VS will show you the line it found the problem on. You can then start looking at the various parts of it to see what value is null and start looking back through your code to find out why. So put a breakpoint at the beginning of the method containing the error line, and run your program from the start again. This time, VS will stop before the error, and let you examine what is going on by stepping through the code looking at your values.

But we can't do that - we don't have your code, we don't know how to use it if we did have it, we don't have your data. So try it - and see how much information you can find out!

Posted 23-Nov-15 23:24pm

OriginalGriff

Solution 3

Try Below Code :-

C#

Label lbl_aprTotalamount = (Label)e.Row.FindControl("lbl_aprTotalamount");

Posted 24-Nov-15 0:01am

sanjay243657

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Anil Sharma1983 · Accepted Answer · 2015-11-23T23:47:00

C#

Label lbl_aprTotalamount = GridView1.FindControl("lbl_aprTotalamount") as Label;

this line gave error because when it lies muliple rows. so please modify your code this way

ASP.NET

<FooterTemplate>
            <asp:label id="lbl_decTotalamount" cssclass="footer_text" runat="server" text="1" xmlns:asp="#unknown"> </asp:label>
            </FooterTemplate>

C#

Label lbl_aprTotalamount= (Label)e.Row.FindControl("lbl_aprTotalamount");