Database

Re: sense these changes immediately and notify my program

9-Oct-09 4:39

you did not mention which db are you using in case of Sql Server, triggers can help you out

Best Of Regards,
SOFTDEV
If you have knowledge, let others light their candles at it

reza assar11-Oct-09 17:05

reza assar

11-Oct-09 17:05

hi dear softdev
i build a database named "Alarms" but this is not important !
please attention !
i want to notify my windows application , not to notify any other objects in sql server!!!! (how can i use triggers to notify an application?)
and both of application and database will run in a local computer
perhaps i have to use "notification service"
but it is hard to implement and distribute it !
is there any other solution ?
pleeeeeeeeeeeeeeaaaaaaaaase help me! Sigh | :sigh:

Re: sense these changes immediately and notify my program

Ashfield12-Oct-09 3:49

Ashfield

12-Oct-09 3:49

reza assar wrote:
perhaps i have to use "notification service"

That would be the best way, its not difficult if you read up about it. Otherwise all I can suggest is polling for changes

Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP

DataGridView Access Problem [modified]

Grollub8-Oct-09 9:11

Grollub

8-Oct-09 9:11

Hello,

I have been working with VB ADO for some time using Visual Studio 2003 and created several applications connecting to Excel with ADO. However, I have moved to Visual Studio 2008 now and have run into some trouble with the new DatagridView in the latest .NET version. Let me step through the process.

Upon 'Form_Load', I connect to my database, fill the dataset, bind it to my DataGridView in a different Form named, which is publicly defined and created upon startup. I utilize the DataGridView values to populate several text boxes and richtextboxes based upon the data. This is all working great.

The problem came when I tried to create other controls to manipulate this datagridView. The lines I am using to access this are:

Form2.DataGridView1.Item("ColumnName", CurrentRecordRow).Value()

Whenever I try this same line of code through a different subroutine (a button click for example) I get an index out of array error.

Through some troubleshooting, I have managed to discover that the 'RowCount' property of the DataGridView changes to '0' when outside the Form_load subroutine where I populate the DataGridView from the created dataset. (in the FormLoad, the rowcount is 236, when I click a button that shoots a messagebox with the Rowcount again, it says its 0)

This explains the 'index' fatal error generated, but not why the data seems suddenly 'gone' once the form has loaded?

Can anyone make a recommendation of what I may be doing wrong in accessing the data within this DataGridView?

thanks,

Grollub

modified on Thursday, October 8, 2009 3:35 PM

Re: DataGridView Access Problem

Mycroft Holmes8-Oct-09 20:00

Re: DataGridView Access Problem

8-Oct-09 20:00

1 Excel is NOT a database and should not be used as a database. I recommend that you change to either XML files for VERY small volumes or SQL Server/Express for more robust data storage. Take Excel out of the design.

2 When manipulating the data in a datagridview you work with the underlying data container (datatable probably)

3 Check the CurrentRecordRow using a break point, it is probably not set

Grollub9-Oct-09 4:05

Grollub

9-Oct-09 4:05

Thanks very much for the reply.

1.) I agree whole-heartedly. Excel is not a database, I am just trying to get something up and running while I learn MySQL and implement. The spreadsheet is already in place, and I had hoped to get something quick and dirty up and running for those who utilize it... and then come back later and move the program to SQL. (under a time crunch).

2.) In this case, I have a dataset.. should I just move through the dataset itself (make this a public variable?) and just use the DataGridView to display the data?

3.) I checked this... and I set the value right above this... I have checked it using a breakpoint and the index I provide is valid... its just the datagridView that seems to 'lose' rows. Could this be a private vs. public variable issue?

Re: DataGridView Access Problem

Mycroft Holmes9-Oct-09 11:45

Re: standard SqlServer 2008

9-Oct-09 11:45

Take a look at this article[^], it is designed to service the user control but may give you some ideas around the DGV, it uses an XML datasource.

Also look into the use of the bindingsource in the article, adds another layer but is quite useful.

Remember do NOT allow your users to do inline editing in a list control (DGV, listview). I force the user to a dialog for CRUD, supply a toolstrip with Add/Edit/Delete, double click the grid also does Edit. Pop a dialog with selected or blank record for the add/edit, write back to your data store before closing the dialog and reload the grid on a successful CRUD.

This may not suit the purist because there are multiple I/O to the database but it works very well and you can never lost data.

Never underestimate the power of human stupidity
RAH

standard SqlServer 2008

ali_reza_zareian8-Oct-09 8:43

ali_reza_zareian

8-Oct-09 8:43

Is it true that,the database of Visual studio 2008 can't work with sql server 2008?
if it is false,
I want to connect to the sql server 2008 so I can connect but it doesn't work.

Mycroft Holmes8-Oct-09 20:03

Re: standard SqlServer 2008

8-Oct-09 20:03

I was going to reply that VS does not have a database but realised you may mean the database designer, it certainly does connect to VS 2008 (although I never use it there would have been a LOT of noise if it didn't connect to sql server 2008).

Have a look through Connectionstrings.com for the syntax and search for some articles on connection to SQL Server

εїзεїзεїз10-Oct-09 1:01

10-Oct-09 1:01

Their is no reason that it will not work , it works , but question here is worked means connectivity or something else Wink | ;)

Best Of Regards,
SOFTDEV
If you have knowledge, let others light their candles at it

Problem in Query

nagendrathecoder7-Oct-09 21:30

nagendrathecoder

7-Oct-09 21:30

Hello all,

I am trying to execute following query but getting an error as amount us not a valid column:

select itemname,rate,qty,discount,(rate * qty) as amount,(amount -(amount * (disount/100))) as Total from ItemMaster;

Then i try:

select itemname,rate,qty,discount,(rate * qty) as amount,((rate * qty) - ((rate * qty) * (disount/100))) as Total from ItemMaster;

and it worked fine.

I need to execute queries which involves more complex expressions within them.
My doubt is, is there any way to run query by first method so that we don't need to write complex expressions again and again?

Thanks,
Nagendra.

εїзεїзεїз7-Oct-09 21:58

7-Oct-09 21:58

try making Sql Server UDF (User Defined Functions)

Best Of Regards,
SOFTDEV
If you have knowledge, let others light their candles at it

Mycroft Holmes7-Oct-09 22:26

7-Oct-09 22:26

There are a number of methods to achieve a semblance of this, UDF is one, in the above simplistic sample on you could create a view that calcs the amount column, you could create a table variable to hold the equivalent of the view, this would only be valid for the current proc whereas a view persists to the database.

I am in the habit of creating a view for my transaction tables, creating any calculated columns (amount) and joining to the foreign key tables (an example would be an OrderLine to Product table on the ProductID to get the product name in the view).

εїзεїзεїз7-Oct-09 23:03

7-Oct-09 23:03

I agree with you View will be a good option

Best Of Regards,
SOFTDEV
If you have knowledge, let others light their candles at it

Ashfield8-Oct-09 1:23

Ashfield

8-Oct-09 1:23

I would go with the view approach, a UDF can add a large overhead to a simple query, slowing it right down - much more than you would expect.

Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP

Sql Server Access

anishkannan7-Oct-09 19:17

anishkannan

7-Oct-09 19:17

HI

I want to Access SQL Server database from network. What are the configure made in sql server ... If have any step please share with me ... or give proper Url for this scenario...
Thankyou

Re: Sql Server Access

εїзεїзεїз7-Oct-09 22:04

7-Oct-09 22:04

What problem are you facing.

Best Of Regards,
SOFTDEV
If you have knowledge, let others light their candles at it

Re: Sql Server Access

Mycroft Holmes7-Oct-09 22:30