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TheMrProgrammer wrote: But when i run the same sub again,ie when i update the database, it tries to put the data, but in that data some old data is also present
and there comes a msgbox saying that duplicate entries and much more.
Without seeing the relevant parts of your code, any one who attempts an answer is simply guessing.
TheMrProgrammer wrote: one more Q:
the size of the mdb file reaches to 50MB.
is there a way to have the size less?
Again without knowing more about the Database it is almost impossible to tender a cogent reply.
Henry Minute
Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”
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We're going to need more information to help you. How are you adding these records. What error messages are you getting? Are you using a DataAdapter or just straight insert commands? Are your tables constrained to be unique?
Also,
TheMrProgrammer wrote: one more Q:
the size of the mdb file reaches to 50MB.
is there a way to have the size less?
Access database files will retain their size even after records have been deleted. (If you had a .mdb file with thousands of records, then deleted the records, the .mdb file will still be very large in size.) If this is what you are referring to, Yes. You can reclaim what is no longer being used by the file. I think I used one of these articles[^] when I needed to accomplish this goal.
Hope this helps.
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well....
partially you were correct to guess.
what you suggested was not the Q i asked.
But I am glad for the links of these articles.
Thanks.
My initial problem is solved.
It was a case of index.
Let me explain my 2nd Q.
Suppose i have new database D.
In it i write about 20 MB of data.
so the size of D is 20 MB.
What I wish is compress D so the 20MB reduces to a less value.
Is it possible?
TheMrProgrammer
http://www.icbse.com/2009/funny-exam-answers-school-students
http://download.cnet.com/TheCalcMan/3000-2094_4-10958266.html
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You can create a zip file. Here are some articles[^] about how to do that in code. But I'm not sure this is exactly what you are looking for either. In order to use a zipped file you'd have to convert it back to the file type it was before, which would increase it back to it's original size as well. But if you are looking to compress it as a means of archiving or backing up this may work for you.
Good luck!
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I suspect that you are not clearing or reinitialising the variables holding the data after the data is added to your database, therefore some of the data would be written to the database again, on subsequent writes to the database.
Steve Jowett
-------------------------
Real programmers don't comment their code. If it was hard to write, it should be hard to read.
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No No
This was not the case.
thanks anyway for trying to help.
TheMrProgrammer
http://www.icbse.com/2009/funny-exam-answers-school-students
http://download.cnet.com/TheCalcMan/3000-2094_4-10958266.html
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Hi all,
I have a little problem and I hope to find some help:
I'm developing a program (C.F.2-V.B.)that have multiple forms.
I need that when I switch from Form1 to Form2, I can continuing to use some of controls builded in Form1.
For example, if in Form1 I have a ComboBox1 populated with its appropiate items, when I switch on Form2, I need to have the same ComboBox1 (without the need to build a new ComboBox and re-populate it with same values).
Is it possible?
This to avoid to do 2 time the same work, and to save precious memory of device.
Thanks
Ignazio
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Hurricane3000 wrote: I need to have the same ComboBox1 (without the need to build a new ComboBox and re-populate it with same values)
Why?
How much work is involved?
Henry Minute
Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”
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Hi,
I want avoid to have a duplicate of the same ComboBox in memory for 3 reasons:
1 - because application is for devices (Compact Framework)where memory must be used with parsimony. It can contain also 20,000 items
2 - To make more fast application avoiding to populate 2 times 2 different Combobox with the same data.
3 - Because to have 2 ComboBox with same items in the same program not sounds to be an "efficent" solution.
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In that case you might have done better to post your question in the Mobile Development Forum, although it does not seem to be as active as this one.
I have zero exposure to the Compact Framework and therefore do not even know if this would work but you might have one list and use that as the DataSource for both ComboBoxes. Either by having the list in a library assembly, or by passing it as a parameter to the constructor of the Form(s).
Sorry not to be more help. 
Henry Minute
Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”
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Thanks Henry!
Ufortunately in my case the DataSource property is not appliable (and also I don't think that I can have some benefit.)
If not possible differentely, I necessarily will must have 2 ComboBoxes.
Ignazio
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I just got done telling someone else this same thing. You cannot have the same instance of a control in two different containers (forms) at the same time. You can add the combo to the controls collection of the second form by first removing it from the controls collection of the first form. You'll have to move it back before your second form is destroyed or dismissed.
20,000 items in a combo?? I'd seriously rethink the design...
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Thanks Dave,
20,000 items is the maximum, but normally I need to fill the Combo with less than 10,000 items getting data from a text-file.
Applying your suggestion, items are preserved , or will be necessary to re-populate the Combo?
Ignazio
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Hi,
1.
As Dave said, a Control has a single Parent, i.e. one Form holding it. You can't make it work reliably on two forms at the same time.
2.
You might consider replacing your two forms by a single form holding:
1. the common controls (including your ComboBox) once;
2. a TabControl so you can choose which TabPage you want to see (so these pages would contain what was not common on your forms).
3.
anything above 100 items in a list for a user to choose from is a GUI horror. You should avoid this both for the user comfort and for performance; there are many ways to avoid it, most of them have a two-level approach: select something (maybe the first letter of a name, a range of values, a page number, whatever), then in a second control show what satisfies the first selection.
One elegant example is a collapsed TreeView: show all the top-level nodes, but only load the details when one of the nodes gets expanded.
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Hi,
Your suggestion to implement a Tab Control is to consider if in this way there is not the need to re-populate the combo 2 times.
I choosen a Combo to contain 10,000 items as compromise between several exigences including the limitaded space available in a mobile device.
I tryed to use a DataGrid, but I confess I encoutered some difficulties.
Thanks
Ignazio
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with the ComboBox outside the TabControl it would always be visible and have no need to repopulate, unless you want to.
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I have a Class DLL that contains a series of functions to perform calculations, i then have a test console application that calls the class, in this instance the class completes its task within about 10 seconds. I then implemented the same class file, as they are all inside the same solution into my windows form application, set it up to be passed exactally the same data and then ran it, it seems to be running about 100x slower in the windows form application as it was still running on the same data after 5 minutes...any ideas why this would be occuring?
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The difference seems a bit large, but then a lot depends on the size of your windows application, and on whether it needs to do a lot of other things besides running the calculations.
The principle behind the difference is simple. Your console application does not do anything else but perform the calculations, whereas the windows application also runs all the graphical stuff, at the same time when it is trying to do the calculations.
Kind of the same thing as when you copy files with Windows Explorer, or with a console app. The console app will do it much faster, because it doesn't have to bother with showing you graphically what is happening.
My advice is free, and you may get what you paid for.
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That is a huge difference and I am sure that there will be something else that is causing this problem. Hard to tell more as you haven't provided any relevant code snippets. Few questions,
1 - Which build are you running? Release or Debug?
2 - How are you calculating the time?
3 - What your windows application is doing other than calling your class? Time may be spending there.
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Tried both build modes, no difference, time is calculated by how long the program takes to run, the class itself has a form with a progress bar, in console mode the progress completes quickly, in windows form, the progress bar moves extremely slowly.
windows application calls the class, then waits for it to finish. I have tried spawning it into a new thread then having the main application wait for the thread to finish, i have also tried calling it inline, rendered no difference in speed, or lack thereof.
Code snippets are hard as there would be pages of code to even make it all understandable if i did, but it is basically running an recursive sub, up to about 6 levels deep on approx 140 different values, sorting and allocating them around as necessary... then returning a collection of results.
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oRiCLe wrote: time is calculated by how long the program takes to run,
No, no, no. What methods are you USING to calculate the time? Not WHAT are you timing.
oRiCLe wrote: in console mode the progress completes quickly, in windows form, the progress bar moves extremely slowly.
In the console app, there is no progress bar, so the thread isn't doing anything else. In your Windows app, the ProgressBar needs to be redrawn every time you update its value. So, if you're changing the value of the ProgressBar on every iteration of your calcuation, your slowing down your calculation speed dramatically since you're making a change to a property value and you're redrawing a control. Like Luc said, without seeing how you're doing this, we really can't tell you what you did wrong.
oRiCLe wrote: Code snippets are hard as there would be pages of code to even make it all understandable if i did, but it is basically running an recursive sub, up to about 6 levels deep on approx 140 different values, sorting and allocating them around as necessary... then returning a collection of results
If the windows app is written properly, and you don't move the mouse while the app is running, there will be very little to no difference in speed between the two apps.
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There is no valid reason whatsoever why a windows app would be any slower than a console app, provided the coding is correct.
without any code nor any detail all we can do is guess.
my best guess is your calculation takes a huge number of very fast steps and tries to show progress after each little step; repainting a progress bar takes some time, if this costs 100 times more than the calculation itself, it would slow down your app by a factor of 101.
Hence, as a test remove the one statement that updates the progress bar.
As a solution, don't update the progress bar that often.
Anyway, if your screen is 1000 pixels wide, a typical progress bar can only show 1000 different states.
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hi mates,
i don't know where to put this question in message board. anyway, i code in visual basic so i think im in the right board.
here's my problem.
how can i correct this query..
SELECT TOP 10 Avg(CONVERT(real,LTRIM(M_Table.Unit))) AS rValue
,Max(CONVERT(real, LTRIM(M_Table.Unit))) As UnitMAX
,Min(CONVERT(real, LTRIM(M_Table.Unit))) As UnitMIN
FROM M_Table
Is it possible to have a Trim inside the convertion?
If not, does anybody know how can i do it.
I want to convert the M_Table.Unit from nvarchar to real. Where M_Table.Unit is nvarchar
but some of M_Table.Unit has space from the beginning which is got an error "cannot convert real to nvarchar" due to that space that's why i want to remove all whites spaces from the beginning of M_Table.Unit.
C# コードMicrosoft End User
2000-2008
「「「「「「「「「「「「「「「「「「「「「「「「「「「「
The best things in life are free
」」」」」」」」」」」」」」」」」」」」」」」」」」」」
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I almost solve my own problem
i just change this line from
Max(CONVERT(real, LTRIM(M_Table.Unit))) As UnitMAX <br />
to CONVERT(real, LTRIM(Max(M_Table.Unit))) as UnitMAX
but only 1 remaining problem is this line
SELECT TOP 10 Avg(CONVERT(real,LTRIM(M_Table.Unit))) AS rValue
help me.
thanks.
C# コードMicrosoft End User
2000-2008
「「「「「「「「「「「「「「「「「「「「「「「「「「「「
The best things in life are free
」」」」」」」」」」」」」」」」」」」」」」」」」」」」
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There is a separate forum for specific sql questions like this.
However, what does the query analyzer say, is wrong with that line? Or is the problem, that the query is not returning the expected result?
My advice is free, and you may get what you paid for.
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