Re: Number comparisons in VBScript - Visual Basic Discussion Boards

Re: Run Application in 64-bit mode

Brandon-X120004-May-12 9:18

Brandon-X12000

4-May-12 9:18

Thanks for the advice Smile | :)

Simple Thanks and Regards,
Brandon T. H.

Been programming in Visual Basic for 4 years this point forward, and is very good at it (I can even create programs completely on code, without dragging those items from the toolbox). Programming C++ for 1 year so far and the same with C#.

Many of life's failures are people who did not realize how close they were to success when they gave up. - Thomas Edison

Problem using a fixed length string in a structure used as a parameter to a Win32API call

dmt19401-May-12 9:29

dmt1940

1-May-12 9:29

Imports System.Runtime.InteropServices
Public Class Form1
Public Const MAXPNAMELEN = 32 ' max product name length (including NULL)
<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Structure MIDIINCAPS 'Structure def copied from win32api.txt
Dim wMid As Int16
Dim wPid As Int16
Dim vVersion As Integer
<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAXPNAMELEN)> _
Dim szPname As String 'win32api.txt def is String*MAXPNAMELEN
End Structure
Declare Function midiInGetNumDevs Lib "winmm.dll" () As Long
Declare Function midiInGetDevCaps Lib "winmm.dll" Alias "midiInGetDevCapsA" _
(ByVal uDeviceID As Int32, ByVal lpCaps As MIDIINCAPS, ByVal uSize As Int32) As Int32
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim retval As Int32
Dim NumMidiInDevices As Int32
Dim DevCounter As Int32
Dim devicecaps As New MIDIINCAPS
NumMidiInDevices = midiInGetNumDevs()
For DevCounter = 0 To NumMidiInDevices - 1
retval = midiInGetDevCaps(DevCounter, devicecaps, Len(devicecaps)) ' Runtime error msg here
'=======================================================================
'A call to PInvoke function 'MidiInCapTest!MidiInCapTest.Form1::midiInGetDevCaps' has unbalanced the stack. This is likely because the managed PInvoke signature does not match the unmanaged target signature. Check that the calling convention and parameters of the PInvoke signature match the target unmanaged signature.
'========================================================================
Next DevCounter
End Sub
'============================================================================
'I have tried <VBFixedString(MAXPNAMELEN)> instead of Marshall as, in the sructure plus countless tries at int16, int32 etc for the other parameters in the API call,in a fruitless attempt to outwit the known inconsistencies between winapi32.txt data types & .NET but to no avail.

'Can anyone help

End Class

Re: Problem using a fixed length string in a structure used as a parameter to a Win32API call

Dave Doknjas1-May-12 14:13

Dave Doknjas

1-May-12 14:13

The main thing is that the 2nd parameter should be 'ByRef':

Declare Function midiInGetDevCaps Lib "winmm.dll" Alias "midiInGetDevCapsA" (ByVal uDeviceID As Integer, ByRef lpCaps As MIDIINCAPS, ByVal uSize As Integer) As Integer

Public Structure MIDIINCAPS
    Dim ManufacturerID As Short
    Dim ProductID As Short
    Dim DriverVersion As Integer
    Dim Label As String
    Dim Support As Integer
End Structure

David Anton
Convert between VB, C#, C++, & Java
www.tangiblesoftwaresolutions.com

Re: Problem using a fixed length string in a structure used as a parameter to a Win32API call

dmt19402-May-12 6:52

dmt1940

2-May-12 6:52

You are right, the main thing was to use byref on the 2nd param. I usually copy Api calls directly from win32api.txt but in this case copied it from someone elses downloaded code Frown | :(

Thanks for the assist

Midigeek

Re: Problem using a fixed length string in a structure used as a parameter to a Win32API call

Luc Pattyn1-May-12 14:20

Luc Pattyn

1-May-12 14:20

Hi,

This article[^] of mine should help you out for most issues.

Yes it may take some experimenting; however for optimum progress, you should fix issues in this order:
1. The stack problem should be solved through the CallingConvention attribute.
2. The numeric parameters or fields should pose no problem, just make sure you use the managed/unmanaged types with matching sizes.
3. The fixed-length string field takes a MarshalAs with SizeConst (not sure a symbolic constant is acceptable); I expect ByValTStr is right, the doc says:
Used for in-line, fixed-length character arrays that appear within a structure. The character type used with ByValTStr is determined by the System.Runtime.InteropServices.CharSet argument of the System.Runtime.InteropServices.StructLayoutAttribute applied to the containing structure.

Good luck

Smile | :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

Re: Problem using a fixed length string in a structure used as a parameter to a Win32API call

dmt19402-May-12 7:52

dmt1940

2-May-12 7:52

See my reply to David Anton's ByRef suggestio which was the only change I made. Thanks for the link to your article which also mentions delegates.

Now that Phase one (identify connected MIDI devices) works I shall code the MidiIn phase....watch this space!

Number comparisons in VBScript

vanikanc30-Apr-12 9:56

vanikanc

30-Apr-12 9:56

Hi,

I have two numbers, they are rather large.

So I have
dim A
dim B

A=123456789
B=123456789

I am trying to compare the numbers,

if (A > B) then
code here
else
code here 2
end if

It is not comparing the numbers for some reason and going into the first part of the if statement, which is quite frankly false. I want it to go the second part of the code.

I have tried to cast A and B as cint, that did not work as well.

Any help is appreciated.

Re: Number comparisons in VBScript

Dave Kreskowiak30-Apr-12 13:18

Dave Kreskowiak

30-Apr-12 13:18

Without seeing your actual code, it's pretty much impossible to tell you what's wrong. From your description, it's possible that you might be comparing strings and not the values they represent.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak

Re: Number comparisons in VBScript

vanikanc30-Apr-12 14:33

vanikanc

30-Apr-12 14:33

you are right on the dot! But how can I make this code compare as numbers? I tried to cast as number and it did not work. I used cint.

Re: Number comparisons in VBScript

Midnight Ahri30-Apr-12 15:38

Midnight Ahri

30-Apr-12 15:38

have you tried not to use CInt and dim an integer variable?

Re: Number comparisons in VBScript

Dave Kreskowiak30-Apr-12 16:04

Dave Kreskowiak

30-Apr-12 16:04

What did I just say about seeing the relevent code??

A guide to posting questions on CodeProject[^]

Dave Kreskowiak

Re: Number comparisons in VBScript

vanikanc1-May-12 2:34

vanikanc

1-May-12 2:34

It look just like what I mentioned in my intial email.

if (A > B) then
code1
else
code2
end if

I have also tried it this way:
if ((cint(A) > cint(B))
code1
else
code2
end if

Re: Number comparisons in VBScript

Dave Kreskowiak1-May-12 4:03

Dave Kreskowiak

1-May-12 4:03

That's only the compare, not the relevant code. What is supply these variables you are comparing???

A guide to posting questions on CodeProject[^]

Dave Kreskowiak

Re: Number comparisons in VBScript

vanikanc1-May-12 6:35

vanikanc

1-May-12 6:35

Thanks for all your help.

I used CDbl to on the number and it is working.

why I lose data after chnage the code or add code

romo2228-Apr-12 13:44

romo22

28-Apr-12 13:44

Hi guys I have very big question

I have a project on Visual Studio, this project include table SQL data. I notice when I add records or add rows with information . imagine that I add more than 1000 rows full with a lot of names and number. the crazy thing that all these data will be removed once I change a little code or add. I wonder how can I protect my data even I make change code time to time.

Re: why I lose data after chnage the code or add code

Wes Aday28-Apr-12 14:33

Wes Aday

28-Apr-12 14:33

What makes you think that changing the code in your project magically causes the data in the database to disappear?

Why is common sense not common?
Never argue with an idiot. They will drag you down to their level where they are an expert.
Sometimes it takes a lot of work to be lazy
Please stand in front of my pistol, smile and wait for the flash - JSOP 2012

Re: why I lose data after chnage the code or add code

Richard MacCutchan28-Apr-12 21:37

Richard MacCutchan

28-Apr-12 21:37

Probably those crazy things he mentioned.

Binding 100,000 items to a list box can be just silly regardless of what pattern you are following. Jeremy Likness

Re: why I lose data after chnage the code or add code

Wes Aday29-Apr-12 2:19

Wes Aday

29-Apr-12 2:19

Richard MacCutchan wrote:
crazy things

Yeah probably. I would not be able to guess which one, out of the 4 or 5 billion crazy things that it could be, is causing the problem

Re: why I lose data after chnage the code or add code

romo2229-Apr-12 0:06

romo22

29-Apr-12 0:06

well that what happen to me every time I create SQL table and after save some record like add rows full with information it will be saved and fine but once I change any code or for example create new button on the form the data on the GridviewData will disappear I am not sure if that because I have to change something on the Proprieties

Re: why I lose data after chnage the code or add code

Wes Aday29-Apr-12 2:16

Wes Aday

29-Apr-12 2:16

romo22 wrote:
I have to change something on the Proprieties

I would have to say no.... the things that you are describing is not possible. If your data was saved then it was saved. You are possibly creating a transaction and not committing. More likely you are clearing the table somewhere in your code. Adding a button to your project will not magically make data in a database just disappear.

Re: why I lose data after chnage the code or add code

phil.o29-Apr-12 4:37

phil.o

29-Apr-12 4:37

Trying to guess what is going on from what you told us is quite tough...

What could happen is that you have your database as a .sdf or .mdb file ; when you change your code, and recompile, the datafile is copied to the output directory.

So when you recompile, you overwrite the datafile in the output directory of your projet (the datafile that your application is actually using).

But it's just a guess. Unfortunately I lost my crystal ball Smile | :)

...No memory stick has been harmed during establishment of this signature.

Re: why I lose data after chnage the code or add code

romo2229-Apr-12 12:10

romo22

29-Apr-12 12:10

thanks guys for helping me

I did something to make my question clear

watch this YouTube you can see my question

please watch with full screen

http://www.youtube.com/watch?v=jDj_ZD10y0k&feature=youtu.be[^]

thanks guys

Re: why I lose data after chnage the code or add code

Richard MacCutchan29-Apr-12 23:03

Richard MacCutchan

29-Apr-12 23:03

Please don't expect people to go to other sites to try and understand your question. Explain clearly what your problem is, showing code extracts where necessary, and show what results you expect and what you get.

Binding 100,000 items to a list box can be just silly regardless of what pattern you are following. Jeremy Likness

Re: why I lose data after chnage the code or add code

Midnight Ahri29-Apr-12 23:55

Midnight Ahri

29-Apr-12 23:55

you don't even tell us your billion data gone from database or dataset.. Dead | X|

Re: why I lose data after chnage the code or add code

Richard MacCutchan30-Apr-12 0:04

Richard MacCutchan

30-Apr-12 0:04

Why are you telling me this?

Binding 100,000 items to a list box can be just silly regardless of what pattern you are following. Jeremy Likness

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.