How do i...this is a code of update button,

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salamo 3alaykoum
i'm a biginner of C# and i want to execute a button Update, that it suceptible to update any Line Of DataGridView, but when i put the button some errors is showed
as ==> int a = Convert.ToInt32(selectedRow.Cells[0].Value);
please if anyone had a solution text me

private void button3_Click(object sender, EventArgs e){
           int selectedrowindex = admuserDataGridView.SelectedCells[0].RowIndex;
           DataGridViewRow selectedRow = admuserDataGridView.Rows[selectedrowindex];
           //int a = Convert.ToInt32(selectedRow.Cells["ItemId"].Value);
           int a = Convert.ToInt32(selectedRow.Cells[0].Value);
           try{cmd.Connection = cnx;
               cmd.CommandType = CommandType.Text;
               cnx.Open();
cmd.CommandText = "update admuser set Designation = '" + textdes.Text + "', Quantity = '" + txtQ.Text + "', PR = '" + textpr.Text + "', PO ='" + textpo.Text + "',Main Asset = '" + textMain.Text + "',Sec Asset = '" + textSec.Text + "',Serial Number = '" + textsn.Text + "',Process = '" + textp.Text + "',Supplier = '" + textSp.Text + "',Status = '" + textSt.Text + "',Original Project = '" + textorp.Text + "',Current Project = '" + textcup.Text + "', purchasing date = '" + timer.Value.Date.ToString() + "', Price = '" + textprice.Text + "',Dep Period = '" + textDep.Text + "',NBV = '" + textNBV.Text + "',State = '" + textState.Text +  "' where Item=" + a ;
               cmd.ExecuteNonQuery();
               cnx.Close();
               MessageBox.Show("U :D ", "PS");
               this.Close();
               Administrator ad = new Administrator();
               ad.Show();}
           catch(Exception ex){MessageBox.Show(ex.ToString()); } } }

What I have tried:

i'm a biginner of C# and i want to execute a button Update, that it suceptible to update any Line Of DataGridView

Posted 13-Apr-17 2:16am

Si Mohammed

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Comments

[no name] 13-Apr-17 8:20am

The most likely thing is that whatever is in selectedRow.Cells[0] can't be converted to an int. But since you made the decision not to tell us what the error is, that is just a guess. What I don't need to guess at though, is you inviting people to wipe out your database through an SQL inject attack.

Si Mohammed 13-Apr-17 8:47am

It's juste an excercice bro like a test,
So i don't care about SQL inject attack
However
Why the SelectedRow.Cell[0] can't be converted to an int

[no name] 13-Apr-17 9:11am

"It's juste an excercice bro like a test", so what? Do it right the first time and then you won't have to do it over and over and over again.
"Why the SelectedRow.Cell[0] can't be converted to an int", well, off hand I would say that it's because whatever is in SelectedRow.Cell[0] isn't a string that can be converted to an int. Just like I ALREADY told you.

Si Mohammed 13-Apr-17 9:49am

Thank you about your advice

ya i anderstaud,
thanks again

Dave Kreskowiak 13-Apr-17 9:16am

You better care about it because what you're doing in this code is reinforcing really bad habits and making it far harder to diagnose problems in your code. Rewrite to use parameterized queries instead and you might find that your errors go away.

But, since you didn't think the error messages would be important (THEY ALWAYS ARE!) there's really nothing else solid we can tell you.

Si Mohammed 13-Apr-17 9:54am

But when i see the errors i'm going to be crasy
beacause i don't have many informations or methodes to ignore it

Dave Kreskowiak 13-Apr-17 10:21am

Since you refuse to tell us what the error message are, you're on your own.

Si Mohammed 13-Apr-17 10:51am

Okey (y)

Si Mohammed 13-Apr-17 11:31am

this is the error message

int a = Convert.ToInt32(selectedRow.Cells["ItemId"].Value);

[no name] 13-Apr-17 11:50am

Okaaaay. So the real problem is that you have no idea what the difference is between a line of code and an error message?

Si Mohammed 13-Apr-17 12:19pm

what are you talkin about hahaha ??

Dave Kreskowiak 13-Apr-17 12:04pm

That's not an error message. That's a line of code.

Si Mohammed 13-Apr-17 12:19pm

the Error is in this Line

Dave Kreskowiak 13-Apr-17 12:20pm

WHAT IS THE F***ING ERROR MESSAGE!?!?!

Si Mohammed 13-Apr-17 12:27pm

hol down bro
this is the Error
==> System.InvalidOperationException : La connection n'est pas fermée, l'état actuel de la connection est ouvert
System.Data.ProviderBase.DbConnectionInternal.TryOpenConnection(DbConnection outerConnection , DbConnectionFactory connectionFactory ,

Dave Kreskowiak 13-Apr-17 12:44pm

That's a database error and has absolutely nothing to do with the line of code you posted.

The error means your trying to open a connection that is already open.

I'm out. Have a nice life.

Si Mohammed 13-Apr-17 16:50pm

thank you brother
i think i declare a boolean var in my DataBase
thank you

[no name] 13-Apr-17 8:23am

Check if your "ItemID" column holds numeric data only?
//int a = Convert.ToInt32(selectedRow.Cells["ItemId"].Value);

Si Mohammed 13-Apr-17 8:41am

No is not a numeric data ; is invisible in my Table,
i don't where is the error exactly

[no name] 13-Apr-17 9:04am

so your itemid need to be numeric and non-text to convert to integer here..what value you have in itemid?

Si Mohammed 13-Apr-17 9:46am

The ItemID had many Values, because it generat all Lines in DataGridView, so about that i want to Update with it

Karthik_Mahalingam 13-Apr-17 10:26am

post a screenshot of your datagridview

Si Mohammed 13-Apr-17 11:30am

i don't know hwo i post the screenshot
can you help me to do it

Karthik_Mahalingam 13-Apr-17 11:41am

host in http://imgur.com/ and share the link

Si Mohammed 13-Apr-17 12:18pm

it's Don

http://imgur.com/gallery/BaVOn

Karthik_Mahalingam 13-Apr-17 12:19pm

so what is the issue.

Si Mohammed 13-Apr-17 12:22pm

for exemple if i want Update some line of the DataGridView anything happen

Karthik_Mahalingam 13-Apr-17 12:24pm

are you getting any error?

Si Mohammed 13-Apr-17 12:28pm

ya this it

System.InvalidOperationException : La connection n'est pas fermée, l'état actuel de la connection est ouvert
System.Data.ProviderBase.DbConnectionInternal.TryOpenConnection(DbConnection outerConnection , DbConnectionFactory connectionFactory ,

Karthik_Mahalingam 13-Apr-17 12:47pm

try

if(cnx.State == ConnectionState.Closed)
cnx.Open();

Si Mohammed 13-Apr-17 16:50pm

thank you brother
it's work

Karthik_Mahalingam 14-Apr-17 0:41am

welcome :)

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