Visual Basic Discussion Boards

Re: Byref or Byval : which is faster and consume less memory

Dave Kreskowiak22-Jan-15 17:09

22-Jan-15 17:09

Not quite.

ByVal will NOT make a copy of a reference type. Both ByVal and ByRef will pass a pointer to the object.

The difference is that passing a reference type ByVal makes a copy of the POINTER, not the object.

What's the difference? Passing a reference type ByRef will allow the called method to replace the original object with a new one. Passing a reference type ByVal will not.

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Re: Byref or Byval : which is faster and consume less memory

Dave Kreskowiak22-Jan-15 17:07

Dave Kreskowiak

22-Jan-15 17:07

Yes! Neither is making a copy of the original object. ByRef and ByVal both pass a pointer to the object.

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How to create relationship of 2 tables using OleDbConnection

gwittlock17-Jan-15 11:36

gwittlock

17-Jan-15 11:36

I have a MS Access Database that has 2 tables (for this example)

Table_1 has a Filed named [ID] which is the Primary Key

Table 2 has a field name [tbl1ID]

I want to Create a relationship between Table_2 and Table_1

I tried:

"ALTER TABLE Table_2 ADD CONSTRAINT [tbl1ID] FOREIGN KEY (MyNewID) REFERENCES [Table_1](ID)"

I get the error "Can Not Find Table Or Constraint"

I know Table_1 and Table_2 exists and I know ID is a filed in Table_1 and I know tbl1ID is in Table_2

So can anyone tell me where I went wrong?

Re: How to create relationship of 2 tables using OleDbConnection

PIEBALDconsult17-Jan-15 12:02

PIEBALDconsult

17-Jan-15 12:02

Not sure, but are tbl1ID and MyNewID in the wrong order?

Re: How to create relationship of 2 tables using OleDbConnection

gwittlock17-Jan-15 12:12

gwittlock

17-Jan-15 12:12

Well I flip them per your suggestion and I still Get the same error.

Re: How to create relationship of 2 tables using OleDbConnection

gwittlock17-Jan-15 22:45

gwittlock

17-Jan-15 22:45

Well It Looks like I had a typo after-all. I had a space in the sable name where it should have been an Underscore.

Thanks.

Re: How to create relationship of 2 tables using OleDbConnection

AccessDeveloper29-Jan-15 7:01

AccessDeveloper

29-Jan-15 7:01

I connect them by using a select query. Access is all about tables, querys and records

Click on "connect" button, the progressbar is filled, a label appears writing if it is connected to the support or not

Member 1138076216-Jan-15 10:12

Member 11380762

16-Jan-15 10:12

Good Evening,

I would like to make a progressBar - (Visual Basic Express 2010) vb - connect his PC, for example, the Lego Mindstorm bluetooth.
I click on the "connect" the progressBar should be filled completely, then subsequently a label is displayed by marking "Connected"; if you click on the button "disconnect" the ProgressBar empties completely the label is displayed by marking "disconnected".
While the progressbar fills or empties there must be a connection or disconnection between the PC and the Lego Mindstorm (here).
And displayed directly in the label1 "connected" or "disconnected".
Thank you in advance, I will be very grateful to you.

I'm sorry for details, and expressions that I used.
I hope you understood what I mean.

Best Regards,
William

P.S: This is extremely urgent !!
Thank you to contact me asap for more detail.

Re: Click on "connect" button, the progressbar is filled, a label appears writing if it is connected to the support or not

Eddy Vluggen16-Jan-15 13:15

Eddy Vluggen

16-Jan-15 13:15

Member 11380762 wrote:
P.S: This is extremely urgent !!

To you, yes, not to me. We're volunteers, and I can even choose to ignore the post completely. I would not even be rushed if you were paying.

As for the question, it needs more detail. If connecting consists of a few measurable steps, with the Lego giving you feedback on how connected it is, then yes, you can have a meaningful progressbar.

I'll bet you a banana that it doesn't. In that case you start with an "indeterminate" state, and measure how long it takes. On next startup, take that value as the max and measure again, and adjust the current max. Make it an average for better results.

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

Re: Click on "connect" button, the progressbar is filled, a label appears writing if it is connected to the support or not

Richard MacCutchan16-Jan-15 22:49

Richard MacCutchan

16-Jan-15 22:49

Member 11380762 wrote:
P.S: This is extremely urgent !!

Sorry, not to anyone here.

List containing custom controls

Bart Van Eyndhoven15-Jan-15 23:10

Bart Van Eyndhoven

15-Jan-15 23:10

Hi there,

For some functionality, I'm thinking about developing a custom control. It would be a kind of mini pnnel containing a few basic controls.

On my form, I would then have to create a panel displaying something liek a listbox, but instead of display text, it should be displaying instances of my custom control. When they don't fit in the panel, there should be a vertical scroll bar appearing.

I also need drag & drop functionality. This means I will need to somehow catch per control if a certain other control is dropped on it (like in a TreeView).

Does anyone have any idea about how to get this done? What container control is best to use in this case and how do I use it?

Thanks in advance!

Re: List containing custom controls

Richard Andrew x6416-Jan-15 5:57

Richard Andrew x64

16-Jan-15 5:57

Bart Van Eyndhoven wrote:
Does anyone have any idea about how to get this done?

Derive a new class from UserControl. Add your controls in the UI designer. Develop your code in the source editor. Voila!

The difficult we do right away...
...the impossible takes slightly longer.

Re: List containing custom controls

Eddy Vluggen16-Jan-15 7:38

Eddy Vluggen

16-Jan-15 7:38

Instead of a UserControl, I'd use a Panel. That's the only difference.

Bart Van Eyndhoven wrote:
When they don't fit in the panel, there should be a vertical scroll bar appearing.

AutoScroll[^].

Bart Van Eyndhoven wrote:
I also need drag & drop functionality. This means I will need to somehow
catch per control if a certain other control is dropped on it (like in a
TreeView).

There's a HOWTO on MSDN, a walkthrough and various examples.

Bart Van Eyndhoven wrote:
Does anyone have any idea about how to get this done?

MSDN[^]

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

SNMP Coding for VB 2013

RudyL15-Jan-15 11:11

RudyL

15-Jan-15 11:11

Hi,

I'm new to VB2013 and am looking to generate a small app that will read SNMP data from a device and log it to a file. I came accross this nice little tool An introduction to #SNMP, an Open Source SNMP implementation[^]

It has some small examples but they all seem to have been written for 2008 or older. Does anyone have a newer example of how to use this (assume I needs to do everything) or some other way to perform SNMP GET and Even SET (later task)?

Thanks!

Re: SNMP Coding for VB 2013

Richard MacCutchan15-Jan-15 21:40

Richard MacCutchan

15-Jan-15 21:40

I don't know what you mean by "written for 2008", but you should use the forum at the end of the article for your questions.

Re: SNMP Coding for VB 2013

Eddy Vluggen16-Jan-15 7:44

Eddy Vluggen

16-Jan-15 7:44

Member 11378320 wrote:
It has some small examples but they all seem to have been written for 2008 or
older.

Code examples aren't written for a specific version of Visual Studio. It targets a specific version of the .NET runtime. Now, you can run code that targets "older" .NET versions on newer versions.

If you run into problems using the code, then there's a forum at the end of the article; you could use it to contact the author, he/she might have more ideas. Also, it'd be rather wise to explain what you tried, and what exactly went wrong - if there's an error or exception, than include that. That way the person responding can give usable advice, otherwise they'd have to guess at which examples you tried and what could be happening.

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

Right Mouse Click in TextBox brings up strange menu

KKW_acd15-Jan-15 5:51

KKW_acd

15-Jan-15 5:51

I'm using the Right Mouse click to launch a popup menu, but when I Right Mouse click in the TextBox, a menu appears:

Undo (Grayed)
Cut (Grayed)
Copy (Grayed)
Paste
Delete (Grayed)
Select All
Right to left Reading order
Show Unicode control characters (Grayed)
Insert Unicode control character> (Grayed)
Open IME
Reconversion (Grayed)

After hitting the Esc key, then my popup menu appears.
I have no idea where this is coming from or how to stop it.

Any ideas?

Re: Right Mouse Click in TextBox brings up strange menu

CHill6015-Jan-15 6:00

CHill60

15-Jan-15 6:00

Please don't cross-post ... I've responded to your post in Quick Answers

Re: Right Mouse Click in TextBox brings up strange menu

KKW_acd15-Jan-15 6:48

KKW_acd

15-Jan-15 6:48

Sorry, Didn't mean to cross-post.
Just after I had posted the original, I realized this is where I should have posted. So I did, and went back to remove the original, and you had responded so quickly (Thanks you), before I was able to deleted it.

Re: Right Mouse Click in TextBox brings up strange menu

CHill6015-Jan-15 6:57

CHill60

15-Jan-15 6:57

Either forum would do .. just not both Smile | :)

DJB2 Hash algorithm for VB

SepPax13-Jan-15 11:39

SepPax

13-Jan-15 11:39

SQL

Hi there,

does anybody know where to find a DJB2 Hashing algorithm code or lib for VB.NET?

Re: DJB2 Hash algorithm for VB

Richard MacCutchan13-Jan-15 21:53

Richard MacCutchan

13-Jan-15 21:53

See http://www.cse.yorku.ca/~oz/hash.html[^], that is not exactly difficult to convert to VB.

Re: DJB2 Hash algorithm for VB

SepPax14-Jan-15 6:33

SepPax

14-Jan-15 6:33

Well,

guess you are right about it should not be difficult to be done, but I'm smashing my head on the wall since some time already, keep getting overflow errors and cast errors... WTF | :WTF:

I'm probably not that good in that kind of VB programming, that's why I'm asking if anybody suceeded in have it done and working... and available to share it.

Thanks in advance.

Re: DJB2 Hash algorithm for VB

Richard MacCutchan14-Jan-15 6:58

Richard MacCutchan

14-Jan-15 6:58

Well, I'm not a VB programmer but I can probably help if you show your code and what errors you receive.

Re: DJB2 Hash algorithm for VB

SepPax14-Jan-15 9:54

SepPax

14-Jan-15 9:54

I have tried so many variants that I lost the path Sigh | :sigh:

BTW, the following is one of them

Public Function CRC_calc_crc_bernstein(frame As String, len As Integer)

    Dim crc As UInt16 = 5831
    Dim tmp As UInt16 = 0
    Dim t As UInt16 = 0

    For i = 1 To len

        tmp = Mid(frame, i, 1)

        ' t = (crc << 5) + crc + tmp
        t = (crc * 33) + 1  'this is another variant
        t = t + crc
        t = t + tmp

    Next

    CRC_calc_crc_bernstein = crc

End Function

The main error I get is that usually after few cycles of For I get an Overflow exception
I tried the use of Ctype() and DirectCast() without success, so... I'm almost giving up.

Thanks in advance for your kind help.

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