VbMySQL Forums

VB.NET :: RE: Updating Label with MYsql Data

Author: recycler
Posted: Thu May 08, 2008 8:05 am (GMT 0)
Topic Replies: 3

As usually the case in programming, there are several ways you can do this sort of thing. If you ask six people how they'd do it, you get at least six different recommendations. Here are two suggestions to move you forward:

1. Use the excellent tutorial series written by Mike Hillier here on this very site as examples. You'll have to dig a bit within them to find where he deals with writing to text boxes, but there's a terrific amount of good general MySQL/VB .NET guidance there. You'll find them at http://www.vbmysql.com/articles/vbnet-mysql-tutorials

2. If you are able to set the names of your text boxes to be identical to the names you use for fields in your MySQL table, then a good low-overhead technique is to use the MySQLDataAdapter object and literally walk through the result set in a For...Each loop as per this example. The actual MySQL query string is in the myQuery variable, and myConnection has already been set up elsewhere:

Code:

Try
Using myConnection As New MySqlConnection
myConnection.ConnectionString = My.Settings.MySQLConnectionString
Dim mMySqlDataReader
Using myCommand As New MySqlCommand(myQuery, myConnection)
Try
myConnection.Open()
Catch exErr As MySqlException
MsgBox("Put an error message that's meaningful here - " & exErr.Message)
End Try

mMySqlDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection)
' populate the fields
While mMySqlDataReader.Read()
'controls outside the tabs are ignored
Dim ctl As Control, tb As TabPage
For Each tb In TabControl1.TabPages
For Each ctl In tb.Controls
' You could have many segments to deal with the types of form objects you have;
' This one deals with Textboxes as an example
If TypeOf ctl Is TextBox Then
Dim txt As TextBox = ctl
'if you name your textboxes the same as your column names, you can do the following:
Try
txt.Text = "" & mMySqlDataReader(txt.Name)
Catch
End Try
End If 'ctl Is TextBox

Next 'ctl
Next
End While
myConnection.Close()

End Using
End Using
Catch exErr As MySqlException
MsgBox("Put an error message that's meaningful for this kind of failure here - " & exErr.Message)
End Try

I've made this slightly more interesting by including code to limit your result-pasting only to text boxes inside a tab control. This sort of technique allows you to avoid conflict with other text boxes NOT on a tab control that you might want to leave alone. I leave you to see how to remove that "tab control only" condition if it's not required, or substitute another condition more useful to you.

I hope these two options get you going again. Good Luck!

VB.NET :: RE: Updating Label with MYsql Data

Author: adrianfan
Posted: Thu May 08, 2008 1:55 am (GMT 0)
Topic Replies: 3

Hi recycler,

Thanks for the information.

I am currently using Visual Basic 2008 Express Edition.

Forms had been designed. Now I am doing the coding where by the labels are updated from local MYSQL database.

Done a search. However, none of the search really bring me anywhere close to what I am looking at.

However, is there a way to store mysql data from query into a variable? If yes, how do I go about doing it?

Thanks!

VB.NET :: RE: In two form... when i open connection at my mysql?

Author: goosfancito
Posted: Wed May 07, 2008 11:25 pm (GMT 0)
Topic Replies: 4

Perfect!

Thanks

recycler wrote:

In general the expert view seems to be that you keep your connections open for the minimum time. The reason is that they can consume relatively large amounts of system resources, and this mounts up if your system is complicated and/or is multi-user.

So the recommendation is to open your connection, do whatever you want to do with the database, and then immediately close the connection again, before proceeding with further VB .NET code.

If your application is working happily the way you have it at the moment AND you do not plan to extend it much, you can probably leave things as they are. But as described above, best practice suggests Open, work with the database, and then immediately Close the connection again. The code in the MySQL connector that bridges the gap between VB .NET and MySQL is designed to open and close connections efficiently and even re-use the same code again if possible, so it doesn't matter that you might open/close the connection repeatedly.

HTH.

VB.NET :: RE: In two form... when i open connection at my mysql?

Author: recycler
Posted: Wed May 07, 2008 10:07 pm (GMT 0)
Topic Replies: 4

In general the expert view seems to be that you keep your connections open for the minimum time. The reason is that they can consume relatively large amounts of system resources, and this mounts up if your system is complicated and/or is multi-user.

So the recommendation is to open your connection, do whatever you want to do with the database, and then immediately close the connection again, before proceeding with further VB .NET code.

If your application is working happily the way you have it at the moment AND you do not plan to extend it much, you can probably leave things as they are. But as described above, best practice suggests Open, work with the database, and then immediately Close the connection again. The code in the MySQL connector that bridges the gap between VB .NET and MySQL is designed to open and close connections efficiently and even re-use the same code again if possible, so it doesn't matter that you might open/close the connection repeatedly.

HTH.

VB.NET :: RE: In two form... when i open connection at my mysql?

Author: goosfancito
Posted: Wed May 07, 2008 8:44 pm (GMT 0)
Topic Replies: 4

Very clean,
in the tutorial open before make query..... in my projects i open when start application and close when exit application.
I want to hear view.

Thanks.

recycler wrote:

Hello goosfancito:

Different developers might suggest different approaches to this depending on what else you are doing with connections in your full application.

If you have not already browsed through them, there are some good tutorials in another part of this website:

http://www.vbmysql.com/articles/vbnet-mysql-tutorials

They inlcude one approach to handling connections. Ernest Ebonat, the moderator of this Forum, has some firm ideas on how this should be done which I'm sure he'll share when he next passes through.

I hope this helps.

VB.NET :: RE: In two form... when i open connection at my mysql?

Author: recycler
Posted: Wed May 07, 2008 5:15 pm (GMT 0)
Topic Replies: 4

Hello goosfancito:

Different developers might suggest different approaches to this depending on what else you are doing with connections in your full application.

If you have not already browsed through them, there are some good tutorials in another part of this website:

http://www.vbmysql.com/articles/vbnet-mysql-tutorials

They inlcude one approach to handling connections. Ernest Ebonat, the moderator of this Forum, has some firm ideas on how this should be done which I'm sure he'll share when he next passes through.

I hope this helps.

VB.NET :: RE: Updating Label with MYsql Data

Author: recycler
Posted: Wed May 07, 2008 5:07 pm (GMT 0)
Topic Replies: 3

Hello adrianfan:

Yes, it is possible. VB .NET enables you to display something entered in a text box by a user either in another text box or in a label control. Labels are intrinsically non-editable, and text boxes can optionally be set to be non-editable.

That answer is probably not very helpful without more detail. You might find some guidance if you use a search engine to look for 'beginners VB .NET tutorials' or similar. You can get Visual Basic 2008 Express Edition from the Microsoft website entirely free and experiment away!

Good Luck!

VB.NET :: Updating Label with MYsql Data

Author: adrianfan
Subject: Updating Label with MYsql Data
Posted: Wed May 07, 2008 4:48 am (GMT 0)
Topic Replies: 3

Hi All,

I am new to coding and would like to check if this could be done. Currently, I have a form whereby the user need to enter their names. After which the queried data will be displayed in either label or any other uneditable format. Is it possible?

VB.NET :: In two form... when i open connection at my mysql?

Author: goosfancito
Subject: In two form... when i open connection at my mysql?
Posted: Fri May 02, 2008 10:43 pm (GMT 0)
Topic Replies: 4

Hello,

I have 2 form, form1 and form2. in form2 i do one query.

My question is: where i open connection? in form1 ( this call to form2 ) or in form2 before to make query?

Thanks

VB.NET :: RE: MySQL Workbench OSS 5.0.17 RC released

Author: ebonat2006
Posted: Wed Apr 30, 2008 2:37 pm (GMT 0)
Topic Replies: 5

Hey mrhutch,

I know what you meant, some people don�t like Toad. I personally like it very much. I found on him easy to use and fast development. I use Toad for Oracle and IBM DB2 too.
_________________
Thanks

Ernest Bonat, Ph.D.
Visual WWW, Inc.
www.evisualwww.com

VB.NET :: RE: Server to VB .NET communications

Author: recycler
Posted: Wed Apr 30, 2008 2:17 pm (GMT 0)
Topic Replies: 4

Is that book good? - Yes, no reservations at all!

For ADO.NET, I got Microsoft ADO.NET, by David Sceppa, 2002 (ISBN 0-7356-1423-7. Possibly a bit out of date now if you need to be really up to date, but I just wanted an easy read on how MySQL connector objects might look in VB .NET applications, and the content of the book can easily be generalised to MySQL from its understandable SQL Server bias.

VB.NET :: RE: Server to VB .NET communications

Author: mrhutch
Posted: Wed Apr 30, 2008 2:06 pm (GMT 0)
Topic Replies: 4

*inventive* ~ lol yeah, I've been called that before. Hoping that Ernest comes back with a corker...

Is that book good? I was just about to buy an ado.net book but if thats any good I'll get it.
_________________
www.skepsolutions.co.uk

VB.NET :: RE: Server to VB .NET communications

Author: recycler
Posted: Wed Apr 30, 2008 2:00 pm (GMT 0)
Topic Replies: 4

Hello Matt:

Presumably you're looking for a generic approach that you can use also outside of VB .NET?

It sounds as though it should work but it seems (no offence intended) a very inventive solution!

I can't help still thinking there must be a less clunky way to do it, although I'm a bit stuck for better ideas at the moment. Maybe the good Ernest will come up with some brilliant wheeze.

I'll also re-read my copy of MySQL Stored Procedure programming by Harrison & Feuerstein, O'Reilly, which I cannot recommend highly enough. There are probably some ideas in there.

- Mike -

VB.NET :: RE: Server to VB .NET communications

Author: mrhutch
Posted: Wed Apr 30, 2008 12:39 pm (GMT 0)
Topic Replies: 4

Hi Mike...

I've got exactly the same issue here! In SQL Server I used to use raiseerror in SQL to call xp_cmdshell() to run batch files on the server. It was great, you coulf have a trigger calling a stored procedure which could call any number of batch files / applications server-side....

and all fairly safely as well. Now I really need Mysql to fire out to the OS... The only way I can think of to do it is to create a table with a column for the application (or batch file) path and name in, then get a trigger to update a flag field in the row needed. Then build a simple windows service with a timer that checks the flag every minute and if it has been updated, and if it has, run the corresponding app/batch file... then set the flag back..

I say windows service because in the interests of cross-platform this would be easy enough to do in *nix with shells and cron jobs.

Whaddya think ?
_________________
www.skepsolutions.co.uk

VB.NET :: RE: MySQL Workbench OSS 5.0.17 RC released

Author: mrhutch
Posted: Wed Apr 30, 2008 12:33 pm (GMT 0)
Topic Replies: 5

I agree with recycler.. Current version is much more stable.. I have bever used any of these type of tools to create DB structures from scratch though.. I have a small CMS type project coming up and have decided to use workbench for all the DB design.. We'll have to see if it can hold up and save me time!

I used to use TOAD a few years ago with oracle.. great tool but the GUI just used to make me feel like I was chewing tin-foil! really jarred with me, and I couldn't wait to stop using it!
_________________
www.skepsolutions.co.uk