Visual Basic

List containing custom controls

16-Jan-15 22:49

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

Sorry, not to anyone here.

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

Re: SNMP Coding for VB 2013

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.

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

13-Jan-15 11:39

SQL

Hi there,

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

Richard MacCutchan13-Jan-15 21:53

13-Jan-15 21:53

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

SepPax14-Jan-15 6:33

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.

Richard MacCutchan14-Jan-15 6:58

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.

SepPax14-Jan-15 9:54

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.

Richard MacCutchan14-Jan-15 23:44

14-Jan-15 23:44

Your logic is not the same as described in the algorithm (not sure why). Try:

Public Function Hash_calc(frame As String)

    Dim hash As UInteger = 5831
    Dim nextChar As Char
    Dim temp As UInt32
    
    For i = 0 To frame.Length() - 1
    
        nextChar = frame.Substring(i, 1)
        temp = Convert.ToUInt32(nextChar)
        hash = hash * 33 + temp
    Next

    Hash_calc = hash
    
End Function

I have changed the function name to Hash_calc as that is more meaningful, this is a hashing algorithm, not a CRC. I also changed the integer declarations to UInteger as that makes more sense for use in a 32-bit or 64-bit application. Finally you need to switch off the overflow checking in your projects properties page in Visual Studio.

SepPax15-Jan-15 10:37

15-Jan-15 10:37

Many thanks,

guess the point was about disabling the overflow checking (which I was not aware about).

I need just one more improvement, about getting the Hash_calc result to become a value between 0000h and FFFFh (a WORD). Which would be the correct approach?

Thanks once more.

Richard MacCutchan15-Jan-15 21:38

15-Jan-15 21:38

I guess just go back to using UInt16.

SepPax18-Jan-15 1:55

18-Jan-15 1:55

seems the right choice is Ushort.
I get results within FFFFh now. Thumbs Up | :thumbsup:

Just need to find out why those results are not matching the originator's hash, will debug further.

Richard MacCutchan18-Jan-15 2:17

18-Jan-15 2:17

Make sure that the originator is using exactly the same algorithm, including the hash seed value.

SepPax18-Jan-15 3:32

18-Jan-15 3:32

yes, will ask to set some debugs in order to check it.
The seed is identical, I guess it's something related to the results or maybe Ushort is not the right choice due to positive/negative calculation results.

SepPax18-Jan-15 9:02