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hello frnds,
how can i want to fetch some value from BLABLA table in to combobox using VB 6 how can i code ????
i am using SQL Server 2000 as a database.
how can i write connection string?
please help..
thankx and regards,
koolprasad2003 ![Rose | [Rose]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/rose.gif)
Be A Good S/W Eng... Life is swing with you..Enjoy..
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Hi,
I have this error:
"The CLR has been unable to transition from COM context 0x1a6e78 to COM context 0x1a6d08 for 60 seconds. The thread that owns the destination context/apartment is most likely either doing a non pumping wait or processing a very long running operation without pumping Windows messages. This situation generally has a negative performance impact and may even lead to the application becoming non responsive or memory usage accumulating continually over time. To avoid this problem, all single threaded apartment (STA) threads should use pumping wait primitives (such as CoWaitForMultipleHandles) and routinely pump messages during long running operations."
this piece of code:
sqlcode = sqlcode & "'" & conv_str(System.Text.Encoding.Default.GetString(crs.Fields(cfieldix).Value), "mysql") & "'"
return the information from a blob field
and the function where the error is being thrown is:
Private Function conv_str(ByVal str As String, ByVal provider As String) As String<br />
<br />
Dim i As Integer, nlstr As String, rstr As Object<br />
' string validation check the string for invalid characters<br />
' keep characters that have the Asci code 32-165, 192-255 and 0,8,9,10,13<br />
' fix here the euro_symbol probleme :p<br />
' provider can either be MySQL or MSSQL<br />
Try<br />
str = str.Normalize()<br />
Catch ex As Exception<br />
'remember to make a detailed report of the error here<br />
conv_str = "NULL"<br />
<br />
Exit Function<br />
End Try<br />
<br />
Dim chrCode As Long, j As Long<br />
For j = 1 To Len(str) Step 1<br />
chrCode = Asc(Mid(str, j, 1))<br />
If chrCode < 32 Then<br />
If chrCode <> 0 And chrCode <> 8 And chrCode <> 9 And chrCode <> 10 And chrCode <> 13 Then<br />
str = Left$(str, j - 1) & " " & Right$(str, Len(str) - j)<br />
End If<br />
End If<br />
If chrCode > 165 And chrCode < 192 And chrCode <> 180 Then<br />
str = Left$(str, j - 1) & " " & Right$(str, Len(str) - j)<br />
End If<br />
<br />
Next j<br />
<br />
nlstr = ""<br />
rstr = ""<br />
i = 1<br />
<br />
If (provider.ToLower() = "mysql") Then<br />
While i <= Len(str)<br />
<br />
Select Case Mid$(str, i, 1)<br />
Case Chr(0) ' ASCII NUL<br />
nlstr = ""<br />
rstr = "\0"<br />
Case Chr(8) ' backspace<br />
nlstr = ""<br />
rstr = "\b"<br />
Case Chr(9) ' tab<br />
nlstr = ""<br />
rstr = "\t"<br />
Case Chr(180)<br />
nlstr = ""<br />
rstr = " '' "<br />
<br />
Case "'"<br />
nlstr = ""<br />
rstr = "\'"<br />
<br />
Case """"<br />
nlstr = ""<br />
rstr = "\"""<br />
Case "\"<br />
nlstr = ""<br />
rstr = "\\"<br />
Case Chr(10), Chr(13) ' line feed and carriage return<br />
If nlstr <> "" And nlstr <> Mid$(str, i, 1) Then<br />
' there was a previous newline and this is its pair: eat it<br />
rstr = ""<br />
nlstr = ""<br />
Else<br />
' this is a fresh newline<br />
rstr = LINE_BREAK<br />
nlstr = Mid$(str, i, 1)<br />
End If<br />
Case Else<br />
nlstr = ""<br />
End Select<br />
<br />
If rstr <> "" Then<br />
str = Left$(str, i - 1) & rstr & Right$(str, Len(str) - i)<br />
i = i + Len(rstr)<br />
rstr = ""<br />
Else<br />
i = i + 1<br />
End If<br />
End While<br />
<br />
End If<br />
<br />
<br />
conv_str = str<br />
<br />
End Function<br />
please help.
thanks
-- modified at 4:33 Monday 4th June, 2007
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I don't use MySql so I don't know how much I'm going to be able to help. But, how many bytes is the value that's you're trying to convert to a string?? It would seem that the operation is retrieving a large block of data from the database and it's taking too long. What is this code supposed to be doing? What's in this field?
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hi,
in the fields are xml documents but in bytes.
The field where I have this error is like 9 Mb
and the function reads the bytes and convert each byte for mysql.
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Well, since 9MB takes a while to come out of the database, you might have run into the problem. Doing this with SQL Server exposes this as a stream, avoiding the blocking call waiting for the entire field to transfer all at once.
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Hello,
I am trying to do as following and I am getting the message
"Cross-thread operation not valid: Control 'ProgressBar1' accessed from a thread other than the thread it was created on.":
My Code:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim ind As Integer
Button1.Enabled = False
ProgressBar1.Step = 21
ProgressBar1.Value = 0
Dim trd As Threading.Thread = New Threading.Thread(AddressOf ThreadDo)
trd.Start()
ListBox1.Items.Clear()
For ind = 0 To 50000
ListBox1.Items.Add(ind)
Next
Button1.Enabled = True
End Sub
Private Sub ThreadDo()
ProgressBar1.PerformStep()
If ProgressBar1.Value >= ProgressBar1.Maximum Then
Timer1.Enabled = False
End If
End Sub
Please help
Thank you
Eric H.
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You're not allowed to interact with UI components on another thread. I'd use the BackgroundWorker class and use it's progress notification to tell the main thread to update it's progress bar.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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Thank you much, have you got any simple example on this.
Eric H.
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Thank you, but I already saw it before and it is a litle complicated (I am beginner). I found exactly what I need.
Beginners, see following code:
Option Explicit On
Imports System.ComponentModel
Public Class Form1
Private worker As BackgroundWorker
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
worker = New BackgroundWorker()
worker.WorkerReportsProgress = True
AddHandler worker.DoWork, New DoWorkEventHandler(AddressOf OnWork)
AddHandler worker.ProgressChanged, New ProgressChangedEventHandler(AddressOf OnProgressChanged)
End Sub
Private Sub OnWork(ByVal sender As Object, ByVal e As DoWorkEventArgs)
Dim i As Integer
For i = 1 To 100
System.Threading.Thread.Sleep(10)
worker.ReportProgress(i)
Next
End Sub
Private Sub OnProgressChanged(ByVal sender As Object, ByVal e As ProgressChangedEventArgs)
Invoke(New ChangeProgressBarHandler(AddressOf ChangeProgressBar), e.ProgressPercentage)
End Sub
Private Delegate Sub ChangeProgressBarHandler(ByVal percentage As Integer)
Private Sub ChangeProgressBar(ByVal percentage As Integer)
ProgressBar1.Value = percentage
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
worker.RunWorkerAsync()
End Sub
End Class
Eric H.
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Here is 1 line that will stop that error and you can carry on using a thread.
Control.CheckForIllegalCrossThreadCalls = false
Just put it in the constructor of your form.
There are 10 types of people in the world, those who understand binary and those who dont.
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Yes, but that sucks. The error is there for a reason.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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 You're just upset because you didn't think of it or you don't understand it.
I give lessons on Wednesdays and Thursdays if you'd like to attend.
I know that it could give problems but for basic applications where only one thread accesses a control it is perfect. I have used this plenty of times before and had no problems.
There are 10 types of people in the world, those who understand binary and those who dont.
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smyers wrote: You're just upset because you didn't think of it or you don't understand it.
ROTFL - I know about it and know exactly what it does.
smyers wrote: I have used this plenty of times before and had no problems.
If someone has crossed the road with a blindfold on once or twice without problems, does that make it a good thing to do ? I didn't think so.
I prefer to help people learn to code properly, rather than give them nasty shortcuts that are going to bite them down the track when their code gets a little more complex.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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Christian Graus wrote: If someone has crossed the road with a blindfold on once or twice without problems, does that make it a good thing to do
It wouldn't be a problem if no cars ever drove down that road.
Like I said, using one thread will give you no problems.
PS - What does ROTFL stand for?
PPS - The lessons offer is still open 
There are 10 types of people in the world, those who understand binary and those who dont.
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smyers wrote: Like I said, using one thread will give you no problems.
Fair enough. You're welcome to offer whatever advice you see fit. Experience tells me that if your advice is easier to follow, people will prefer it, even if it's bad.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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Thak you,
I try this as following, but it doen't work
Public Class Form1
Sub New()
' This call is required by the Windows Form Designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
Control.CheckForIllegalCrossThreadCalls = False
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim ind As Integer
Button1.Enabled = False
ProgressBar1.Step = 5000
ProgressBar1.Value = 0
Dim trd As Threading.Thread = New Threading.Thread(AddressOf ThreadDo)
trd.Start()
ListBox1.Items.Clear()
For ind = 0 To 5000
ListBox1.Items.Add(ind)
ListBox1.SelectedIndex = ind
Next
Button1.Enabled = True
End Sub
Private Sub ThreadDo()
ProgressBar1.PerformStep()
If ProgressBar1.Value >= ProgressBar1.Maximum Then
Timer1.Enabled = False
End If
End Sub
End Class
Eric H.
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It seems to me that you should do some reading, and perhaps not worry about threads for a while until you've got a greater understanding of more basic things.
When asking a question, you should also define 'doesn't work', that doesn't tell us anything. Does it blow up ? Does it not do what yuo wanted ? Does it do anyting at all ? We don't know. Telling us the line that blows up and the error would also help.
And, what you're doing now is telling the framework not to protect you from yourself. This may work fine for such a simple app, but you'd do better to learn how to use a more powerful thread class ( BackgroundWorker ) and to ensure that your UI access is all in one thread. Then you can write *good* code, instead of just code that compiles.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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You right, when I am saying doesn't work, it means in this case that first the listbox fullfilled and then the progressbar get to 100%. I don't see any thread working.
I am sorry my english is not mother tongue, I hope you understand
Thanks
Eric H.
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Your code makes no sense at all - your progress bar is running in a different thread to the thing you're tracking progress on. The thread that's adding to the listbox, should be the thread that runs the progress bar, otherwise there's no relationship between the progress made and the state of the bar.
The code also calls a thread, outside of a loop, which will just step the progress bar once. And then it stops a timer, which we can't even see.
Overall, this code shows every sign of you're being well out of your depth with the concepts you are playing with, I'd recommend working through a decent book and trying to learn some basics.
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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If it is so easy for you to do this why don't you show me the solution like that I will be able to appropriate this easy example to my difficult application?
In my side, I will continue to learn VB.NET in my rythm.
Thank you
Eric H.
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I just tried to run this code and it runs. Don't know what you trying to do though.
There are 10 types of people in the world, those who understand binary and those who dont.
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the listbox is fullfilled but the progressbar doesn't progress in parallel while the listbox is adding items.
First the listbox add items
second the progressbar =100%
Isn't it?
Thank you
Eric H.
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I have finished my Project with no Errors, i try to Buld it, it will take time to Bring results and it will not Display my Results. it gives me an Errors saying"Just in Time Error" and it will Build
"
Preparing resources...
Updating references...
Performing main compilation...
"
for the Whole day. my sysytem is fast and i try to Google the Problem before i post.
Help
Vuyiswa
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