Re: what's wrong, Object reference not set to an instance of an object. - C# Discussion Boards

Re: When to declare windows service application settings

Sunny Ahuwanya6-Jan-09 10:46

Sunny Ahuwanya

6-Jan-09 10:46

I'd go for the simplest solution first, which is onStart (also takes care of Restart)

Sunny Ahuwanya

"The beauty of the desert is that it hides a well somewhere"
-- Antoine de Saint Exupéry

what's wrong, Object reference not set to an instance of an object.

suni_dotnet6-Jan-09 9:47

suni_dotnet

6-Jan-09 9:47

Hi,
whats wrong in this code. iam getting this error at AddWithValue. what value i need to set for what.

protected void GridView2_RowUpdating(Object sender, GridViewUpdateEventArgs e)
{
string connectionstring = WebConfigurationManager.ConnectionStrings["RoyalHotelManagement"].ConnectionString;
SqlConnection con = new SqlConnection(connectionstring);
SqlCommand cmd = new SqlCommand("InsertSuite", con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@filleddate", GridView2.SelectedRow.Cells[3].Text);
cmd.Parameters.AddWithValue("@freedate", GridView2.SelectedRow.Cells[4].Text);
cmd.Parameters.AddWithValue("@nameofcustomer", GridView2.SelectedRow.Cells[7].Text);
try
{
con.Open();
SqlDataReader reader = cmd.ExecuteReader();
}

thanks in advance

Re: what's wrong, Object reference not set to an instance of an object.

Jon Rista6-Jan-09 10:00

Jon Rista

6-Jan-09 10:00

I am guessing that something in the GridView is null. It could be:

1. SelectedRow, if there is no selected row.
2. Any of the cells
3. The Text value of the cell (null string)

Re: what's wrong, Object reference not set to an instance of an object.

suni_dotnet6-Jan-09 10:17

suni_dotnet

6-Jan-09 10:17

hi,
yes database values are null(gridview is populated with database values), i need to input the values through gridview in edit mode.

Re: what's wrong, Object reference not set to an instance of an object.

Jon Rista6-Jan-09 14:34

Jon Rista

6-Jan-09 14:34

I understand that the database values are null...I was talking about GridView values. Your NullReferenceException is most likely because the SelectedRow is null, or the Text of one or more Cells is null. Both will cause a NullReferenceException.

Re: what's wrong, Object reference not set to an instance of an object.

Pete O'Hanlon6-Jan-09 10:15

Pete O'Hanlon

6-Jan-09 10:15

As has already been said, it could be a null SelectedRow, or the value in the Cells might be null. What you need to do is put a breakpoint on the line with the first AddWithValue (just click F9 to insert the breakpoint), and then run the application. When you hit this method, hover your mouse over the different properties until you see one that pops up the tooltip "null".

There - now you know how to solve these issues for yourself.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

My blog | My articles | MoXAML PowerToys

Re: what's wrong, Object reference not set to an instance of an object.

suni_dotnet6-Jan-09 10:22

suni_dotnet

6-Jan-09 10:22

hi,
but i need to input values to the blank cells. i cannot populate them with some other values. they has to be null/blank.

Re: what's wrong, Object reference not set to an instance of an object.

Rutvik Dave6-Jan-09 11:17

Rutvik Dave

6-Jan-09 11:17

First of all try to explain what you want to do with the code.

if you want to store the value (which is added directly in the gridview) in the database,

then try to use GridView2.Rows[e.RowIndex].Cell[3].Text for all the cells, becuase it can be possible that no rows selected at that time.

also assign the Values of the gridview to some variable and the check wether the value is null or not.

i.e.

string FilledDate = GridView2.Rows[e.RowIndex].Cell[3].Text;
if (FilledDate != null)
    cmd.Parameters.AddWithValue("@filleddate", FilledDate);
else
    cmd.Parameters.AddWithValue("@filleddate", ""); // or give appropriate error messege instead of inserting blank values.

-----------------------

or you can use directly

e.NewValues[3] Instead of GridView2.SelectedRow.Cells[3].Text
in your original code.

e.NewValue will give you all the new updated values.
e.OldValue will give you all the old existing values.

do this for all the fields.

and one more thing give GridView2 some appropriate Name, instead of using auto generated name.

Re: what's wrong, Object reference not set to an instance of an object.

Wendelius6-Jan-09 11:18

Wendelius

6-Jan-09 11:18

This is quite confusing. Your procedure name is InsertSuite, which sounds like you're inserting data into the database. However you're executing a reader so it seems like you're actually fetching data. This is also the impression from your replies.

If you're trying to update the database I think you should use e.RowIndex to get the actual row, but if you're trying to fetch the data I think you should use different event since RowUpdating is raised when rows update button is clicked.

The need to optimize rises from a bad design.My articles[^]

HOW CAN MADE MESSENGER IN C#.NET?HOW CAN MADE STUDENT FORM IN C#.NET?

mohammedali20066-Jan-09 9:25

mohammedali2006

6-Jan-09 9:25

SALAM SIR;
HOW CAN MADE MESSENGER IN C#.NET?
HOW CAN MADE STUDENT FORM IN C#.NET?
THANKS SIR

mohammedali

Re: HOW CAN MADE MESSENGER IN C#.NET?HOW CAN MADE STUDENT FORM IN C#.NET?

EliottA6-Jan-09 9:28

EliottA

6-Jan-09 9:28

Forth time already? No means no, go away. A student can research[^] or even go to a class[^] every now and then and LEARN SOMETHING.

We are NOT going to do your work!

To get you to stop posting this, pay a real coder over at rentacoder[^] where they will be glad to do your work... for money.

Re: HOW CAN MADE MESSENGER IN C#.NET?HOW CAN MADE STUDENT FORM IN C#.NET?

Dave Kreskowiak6-Jan-09 9:54

Dave Kreskowiak

6-Jan-09 9:54

EliottA wrote:
pay a real coder over at rentacoder[^]

OMG, that was funny! Laugh | :laugh:

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

Re: HOW CAN MADE MESSENGER IN C#.NET?HOW CAN MADE STUDENT FORM IN C#.NET?

EliottA6-Jan-09 9:56

EliottA

6-Jan-09 9:56

You know what I mean Dave.
Laugh | :laugh:

Re: HOW CAN MADE MESSENGER IN C#.NET?HOW CAN MADE STUDENT FORM IN C#.NET?

Dave Kreskowiak6-Jan-09 10:43

Dave Kreskowiak

6-Jan-09 10:43

Oh, of course I do! Laugh | :laugh:

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

Re: HOW CAN MADE MESSENGER IN C#.NET?HOW CAN MADE STUDENT FORM IN C#.NET?

fuad_200025-Mar-10 22:26

fuad_2000

25-Mar-10 22:26

hi
am search from someone who can make small program for me

thank you

f0f020002000@yahoo.com

Re: HOW CAN MADE MESSENGER IN C#.NET?HOW CAN MADE STUDENT FORM IN C#.NET?

Dave Kreskowiak26-Mar-10 1:59

Dave Kreskowiak

26-Mar-10 1:59

Then you've come to the wrong web site. Usually, that's for some homework assignment or some contract job that the person took on and has no idea how to do it. In either case, noone is doing you anyn favors by doing your work for you.

If you want something written for you, go to http://www.RentACoder.com[^]

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Re: HOW CAN MADE MESSENGER IN C#.NET?HOW CAN MADE STUDENT FORM IN C#.NET?

Xmen Real 6-Jan-09 14:57

Xmen Real

6-Jan-09 14:57

EliottA wrote:
where they will be glad to do your work... for money.

yes yes, i will be glad... Laugh | :laugh:

TVMU^P[[IGIOQHG^JSH`A#@`RFJ\c^JPL>;"[,*/|+&WLEZGc`AFXc!L
%^]*IRXD#@GKCQ`R\^SF_WcHbORY87֦ʻ6ϣN8ȤBcRAV\Z^&SU~%CSWQ@#2
W_AD`EPABIKRDFVS)EVLQK)JKSQXUFYK[M`UKs*$GwU#(QDXBER@CBN%
Rs0~53%eYrd8mt^7Z6]iTF+(EWfJ9zaK-iTV.C\y<pjxsg-b$f4ia>
--------------------------------------------------------
128 bit encrypted signature, crack if you can

Re: HOW CAN MADE MESSENGER IN C#.NET?HOW CAN MADE STUDENT FORM IN C#.NET?

Wes Aday6-Jan-09 9:30

Wes Aday

6-Jan-09 9:30

mohammedali2006 wrote:
HOW CAN MADE MESSENGER IN C#.NET?
HOW CAN MADE STUDENT FORM IN C#.NET?

Your questions do not make any sense so it is unlikely that you will get any kind of helpful answer

Why is common sense not common?
Never argue with an idiot. They will drag you down to their level where they are an expert.
Sometimes it takes a lot of work to be lazy
Individuality is fine, as long as we do it together - F. Burns

Re: HOW CAN MADE MESSENGER IN C#.NET?HOW CAN MADE STUDENT FORM IN C#.NET?

EliottA6-Jan-09 9:42

EliottA

6-Jan-09 9:42

Review his posts. Its been a couple of months, he is probably redoing some course that he didn't study for again. He wants an Instant messenger of some kind coded in .net given to him so he can change the name and submit it.

CP IGNORE THIS USER FOREVER

leckey6-Jan-09 9:39

leckey

6-Jan-09 9:39

1. Repeat, repeat, repeat...repeat!
2. All caps
3. Can't use Google

"Well, we're getting "F"'d at work. WPF, WCF, and WWF... WTF?" --John Simmons

Re: CP IGNORE THIS USER FOREVER [modified]

CPallini6-Jan-09 9:42

CPallini

6-Jan-09 9:42

Please don't be so rude: add 'SALAM SIR' Roll eyes | :rolleyes:

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: CP IGNORE THIS USER FOREVER

EliottA6-Jan-09 9:43

EliottA

6-Jan-09 9:43

don't forget to address him as sir!

Re: CP IGNORE THIS USER FOREVER

CPallini6-Jan-09 9:44

CPallini

6-Jan-09 9:44

Fixed.