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hi, i still dont understand the concept of "stream", more specifically:
System.IO.Stream
System.IO.MemoryStream
Here's a code fragment in VB.NET:
Dim HSBCWC As new Customer()
HSBCWC.ID = 08346
HSBCWC.FirstName = "Paul"
HSBCWC.LastName = "Bowie"
...
Dim stream As MemoryStream()
Dim serializer As New XmlSerializer( Customer.GetType() )
serializer.Serialize( stream, HSBCWC ) QUESTION 1: Why not serialize to a string as supposed to a MemoryStream? It would be much simpler rite?
...
stream.Flush() QUESTION 2: I dont understand why we need to flush? flush what from what? I thought HSBCWC has already been "flushed" to stream?
stream.Seek(0,SeekOrigin.Begin) however, I do understand why u need to Seek (rewind the stream).
...
Dim reader As New StreamReader(stream)
message.body = reader.ReadToEnd()
stream.Close()
SmptMail.Send(message)
I'm a newbie and pretty confused why we need "streams" in general.
help! 
SHAME
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"The MemoryStream class creates streams that have memory as a backing store instead of a disk or a network connection."
I thought MemoryStream is a memory object (data in RAM). So, "Flush" will flush this data (already in memory) to another memory location???
help!
norm
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Streams are supposed to be a higher-level abstract concept. An example: If you make a compression routine that compress one file to another, it will do just it.
But if you create a routine that compresses a input stream into a output stream you can use this routine in ,e.g., serial ports, sockets, HTTP, files, and even memory, without changing it.
So, a memorystream is useful when you want to use a routine that does something in/from a stream but do not want to have a file writing/reading overhead.
The flush method does nothing: it's there only to make the interface consistent.
Concussus surgo.
When struck I rise.
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Thanx for the feedback first of all.
(1) but in the code fragment that i showed earlier, why not Serialize to a "String" as opposed to a "MemoryStream"
(2) Quote: "An example: If you make a compression routine that compress one file to another, it will do just it."
what do u mean by "it will do just it"?
norm
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I'm currently buidling an ASP.NET application that requires custom HTML emails be sent. I was going to use "Sever.Execute" to capture the result of an aspx template execution and use it as the body of an HTML email. This works, but it only works if it is called from the "Page_Load" Sub. As soon as I call it from an event sub it fails and returns a "Corrupt ViewState" Error. Is this normal? Does "Server.Execute" only work in Page_Load? Is there another/better way to do this? Help is appreciated.
Code:
**** This Works ****
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
SendItDude()
End Sub
**** This Doesn't Work ***
Private Sub btnSend_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSend.Click
SendItDude()
End Sub
Public Sub SendItDude()
Dim EM As CarSystem.Emailer = New CarSystem.Emailer()
Dim writer As New StringWriter()
Dim x As Integer = 1
Dim List(x) As Integer
List(0) = 3332
List(1) = 3332
Server.Execute("../Assignpreview.aspx?car_id=7", writer)
Response.Write(EM.Email_it(8, List, 3332, "This is a test", writer.ToString()))
End Sub
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I would like to write a control panel applet, but have only found examples in C++
Can anyone guide me to some sample code on creating applet
Cheers
Geoff
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I'm not a VB developer, but am in charge of implementing PVCS for our development team. The problem I've come across is that when I load up a VB project now, the Project View Tree does not display available forms, or anything really. I cannot figure out how to get this view back to displaying properly. Can someone help me, please?
We're running VB6, and PVCS VM6.8.
I don't know if this is a known VB anomaly or something to do with PVCS IDE add-on. Thanks.
BW
{insert witty/thought-provoking saying here}
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Has anyone ever seen an issue in VB6 Where a call to Time or Date fails without an error message?
Actually now that I think about it there could be more than one thing here.
1. If an error is generated during the Load procedure of a Form, are any of the controls updated?
2. Is there any type of system or user permissions that would cause the Time or Date functions to fail at runtime?
Basically, I have a form that is very simple it sets two dt pickers and then reads in data from an ini file and puts it all onto controls on the screen. It works great on 3 different systems, but on the fourth the form shows with no errors, but all the controls are blank (not filled in, but completely drawn).
I don't think there is a code issue, but I'm trying to narrow my search to find out why this one system is different than the others.
From an internal company e-mail November, 2001 --
"Would the person who stole the ethics training manual from the class last Friday please return it."
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I'm using VB 6.I want to show a bitmap field from database.When I use acceess 97 database its ok but for access 2000 I can not show it.Is there any trick for it?Or is there any veiwer component for access 2000?
Mazy
"If I go crazy then will you still
Call me Superman
If I’m alive and well, will you be
There holding my hand
I’ll keep you by my side with
My superhuman might
Kryptonite"Kryptonite-3 Doors Down
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Can anybody help me to handle keypress event in Datagrid Columns? I have to validate the data entered in a column for that I need to have the keypress event of datagrid columns.
I have tried with DataGrid_Keypress Event but that does fire the key press event.
Please provide urgent help 
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I want to add a new webform using C# for the codebehind in an existing ASP.NET application using VB but there is no option under the menu Add new file to select C# webform. (I use Visual Studio .NET) I try to create the aspx and aspx.cs file in a different C# project and copy the files over but when I try to open the web page the browser display the error message that it does not find the class for the codebehind. Is there a way to do it or I have to stuck with one language under a web project. Anybody have any idea or solution for this? I want to gradually convert my project from VB.Net to C#.Net and I hope a lot other people might have the same problem. It is ok if you can show me a link to any website or document on how to do this I will be so happy. Thank in advance.
Young Huynh
John World
Senior Software Engineer
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I'm having a problem with a program that needs to figure out which (if any) of the PC card slots in a laptop a particular card is in. I guess I either need to interigate the CIS tuples in some way, or (probably "safer") ask the WinAPI for the list of devices it can see, but can anyone point me in the direction of the correct calls to make please? I'm writing in VB6 under NT4/2000 if that makes any difference. Thanks.
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Upgrade Failed: Exception occured The referenced Component CommonDialog is missing a design timr license ?
I get the above error when I attempt to upgrade my VB 6.0 project to VB.NET. Can anyone shed any light on this error. I am lost. I have licenses for both products. Had anyone had this error?
Sincerely,
Derek S. Smigelski
derek@smigelski.com
Dereks@mip.com
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Hi Friendz!
Do any one know how to close a running exe in vb 6.0
PLz tell me as early as possible.
Work Hard and Test your Luck
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Looks like Ray's solution should work, the basic idea is that you will need the handle to the window you want to close. Once you have the handle to the window you will then send a message to the message queue passing it the WM_CLOSE message to close that Window. So all you need is something like this:
Define these in a module:
Public Declare Function SendMessage Lib "user32.dll" Alias "SendMessageA" (ByVal hWnd As Long, ByVal _
Msg As Long, wParam As Any, lParam As Any) As Long
Public Const WM_CLOSE = &H10
Your code:
Dim hWnd As Long
'You will want the handle to the window you want to close
'however this is just an example with the handle to the
'current window.
hWnd = Me.hWnd
result = SendMessage(hWnd, WM_CLOSE, ByVal CLng(0), ByVal CLng(0))
HTH
Nick Parker
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See Api PostMessage
Oberdan
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I built a webcontrol that has several properties, one of which is a Collection type. This property works just fine in design view from the Property Browser and brings up the Collection Editor when selected. However, when I run or close the project then re-open the project in design mode my inserted items are no longer visible!!!
What am I missing? I have read that collections must be Type Converted but no good examples are out there in VB.NET!?!?
Thanks!
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Hi
I have a ActiveX control in V.Basic and need to load a bitmap and obtain the handle to use with API functions eg: SelectObject,GetObject,TransparentBlt,etc.
It´s work fine if the image is loaded from a file eg:
hImageGray = LoadImage(App.hInstance, "c:\gray.bmp", IMAGE_BITMAP, 0, 0, LR_COLOR Or LR_LOADFROMFILE)
The problem is when I try to load the bitmap from a resource file added in the ActiveX control project.
I try from different methods:
"ID_GRAY = 102
hImageGray = LoadImage(App.hInstance, CLng(ID_GRAY), IMAGE_BITMAP, 0, 0, LR_COLOR )"
" LoadBitmap(App.hInstance, ID_GRAY)"
"LoadBitmap(App.hInstance, "102") "
Ever with the same result. No work".
Also try to use the v.Basic method to load the image with LoadResPicture, returning a IPictureDisp with the image loaded.
This solution have a problem: the handle property of IPictureDisp isn't a bitmap handle to use with the GDI API´s.
Any ideas to solve this problem???
Thank´s (and sorry by my bad english!
MrSparc.
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Yes, thanks for you help.
Now you are right, the variable does not get set to null at once, but if I try to create a new DC and select an old hBitmap in it, it return error...meaning a bitmap has been deleted successfully. Thanks again.
.
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Haha...sorry man, I clicked it by accident, I actually wanted to reply to your answer to me just two lines before yours in this table.
Anyways, with respect to your question, I had the same problem and never succeeded in loading a bitmap from the resource. I perused all the books I had, Web sites, posted the same question at a several developer, sites...but nope, no answer. I guess it is not possible to explain to an API functions to use a bitmap from a VB resource. They made those wrapper functions to retreive an object from the resource, like LoadResPicture and alike, but it was never meant to be used by API functions. I also find it strange, for it is only logical if you use LR_LOADFROMFILE that you can use another constant to retreive a bitmap from the resource for example...but I don't think it is possible.
Anyways, thanks for your answer to my inquiry, you were absolutelly right.
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This is THE solution:
The solution to load the resource of bitmap in a StdPicture object is really effective!.
I tried to use handle property of the IPictureDisp that returned the LoadResPicture but it failed because he is not handle of bitmap.
Nevertheless, if we assigned the IPictureDisp returned by LoadResPicture in a StdPicture object, the StdPicture.handle is perfect bitmap handle!!
This is the solution that I implemented :
Dim tBitmap As BITMAP
Dim iRes As Integer
Dim picTemp As New StdPicture
' 102 is the ID of a Bitmap in the .res file.
Set picTemp = LoadResPicture(102, vbResBitmap)
hImageGray = picTemp.handle
If hImageGray <> 0 Then
GetObjectAPI hImageGray, Len(tBitmap), tBitmap
' bla bla bla bla.....
........
DeleteObject hImageGray
' I think that this DeleteObject could be cleared since bitmap
' would have to be destroyed when Set picTemp = Nothing,
' but by the doubts that Bill has forgotten to him....
End If
Set picTemp = Nothing
This works excellent.
Mike_spice, when I discovered the solution jumped in a leg. I hope that it serves so much to you as it served my, since in my case, it had a ActiveX and it was already thinking the revolting thing that it would be to distribute bitmap along with the OCX .
MrSparc.
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Folowing are the queries related to VB.NET
1.How to insert & update data into the table from the datagrid?
2.How to put validation in the datagrid while inserting data?
3.how to know the number of rows in the datagrid?
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Hi guys. This one is really driving me crazy.
I create a memory DC, and load a bitmap in it:
MemDC = CreateCompatibleDC(0)
hBitmap = LoadImageA(App.hInstance, szPath, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE)
SelectObject MemDC, hBitmap
and it works fine, I can use it in processing with BitBlt function, now here comes the problem:
lRes = DeleteDC(MemDC)
If lRes = 0 Then
'We have an error deleting a DC, do something...
End If
lRes = DeleteObject(hBitmap)
If lRes = 0 then
'We have an error deleting an object, do something...
End If
but even tho it shows that it has deleted the hBitmap object, it actually didn't, cause I can get its handle from Immediate Pane by typing ?hBitmap. It is impossible to delete hBitmap from memory, and I effectively have a memory leak. Every time I create that object, it never gets deleted from the memory. Trying to delete it before I delete DC doesn't work either, cause DC flags it as being used and thus not deletable.
In C++ it is easy, you create an pOldBitmap at the beginning of the function and then you select it back into DC at the end of the function, so you can delete the bitmap you created, or you use CDC::SaveDC which is fine for MFC but does not have a related function in API. But how to do it here in VB with API functions?
I spent some serious time trying to figure this out, but couldn't. When I check a MemDC in the ImmediatePane of my IDE, like ?MemDC it shows NULL, so it really gets deleted, but if I do ?hBitmap then it shows something like 16110, and even 10 minutes after it will show the same, so the memory never got reclaimed.
Any help would be appreciated. Thanks.
.
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You code this written good, safe with some small corrections.
MemDC = CreateCompatibleDC(hdc)
hBitmap = LoadImageA(App.hInstance, szPath, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE)
hOldBitmap = SelectObject( MemDC, hBitmap )
' bla bla bla
SelectObject MemDC, hOldBitmap
lRes = DeleteDC(MemDC)
If lRes = 0 Then
'We have an error deleting a DC, do something...
End If
lRes = DeleteObject(hBitmap)
If lRes = 0 then
'We have an error deleting an object, do something...
End If
Now the explication:
When call to the function DeleteDCo or DeleteObject, this delete the object from the memory, but not set to zero the variable param.
It is why you sees in the immediate window the same value of handle when typing "?hBitmap ".
The unquestionable test that bitmap was destroyed is to try to use his handle after to have called to DeleteObject(hBitmap).
Good Luck!!
MrSparc.
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