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Hello,
I'm using VB.NET 2008 (framework 3.5).
I would like to check permanently if a new entry (row) is added to a table in particular, but I have no idea about how to do this... (is there some equivalent of the FileWatcher for DB ?...)
Thanks in advance
Etienne
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The service could periodically count (SELECT COUNT(*) FROM ...) the number of rows in the table and when the count increases you know a new row was inserted.
A better solution would probably be to use a FOR INSERT trigger on the table, as described by How to: Create and Run a CLR SQL Server Trigger[^].
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ok, i'm going to try it (with the trigger).
thanks a lot !
etienne
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is there any pivot table kind of control in asp.net / vb.net
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is pivot table kind of control used in data reports
spriya
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Native in the VS toolbox?? No.
You'll have to either write one yourself or use a third party graphing library, like ZedGraph.
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hello, ive been working on a tabbed web browser for a little while now, and it's gotten to the point where i would like to add a favorites, and a history menu, i have tried and tried to implement a history menu and a favorites menu and have failed in trying to do so.
it would be great if you could help me out
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All you have to do is add entries to a collection. They can be as simple as adding string objects to a List(Of String), or an XML document. Either way, you can easily serialize the contents to a file to save/retrieve the list.
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ho guys
can any body please tell me about CSLA , how usefull it is to use CSLA .
hello
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Hi all.
Do you now VB.NET is object oriented? I heard somewhere that VB.NET is text oriented. Is that true ?
Thanks to you
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Seriously? - Or just trolling?
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YA dear vb.net is fully object oriented language.
Thanx
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"Text oriented"?? Never heard of it.
Yes, VB.NET is fully object oriented, as is the entire .NET Framework BCL and .NET CLR.
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If anyone can help with this I'd be grateful! Using VB.2008 express, I'm trying to improve my GPS tracking program by building in the ability to handle multiple large map tiles and tile them into one larger image. Previously I've used only a single map tile and let the program load the one on which the GPS plot is drawn, but there's now a need to scroll across a much larger area of the country. I've searched for code to handle this and come up with only one example which contains the line:-
bltImage = New Bitmap(8000, 8000, Imaging.PixelFormat.Format32bppPArgb)
The map tiles are then read from an array and drawn on the base image.
The '8000' values are mine as the map tiles I'm handling are 4000 pixels x 4000 pixels. I'd very much like to use a dynamic grid of 9 tiles held in the array, which requires the background image (bltImage) to be 12000 x 12000 (I'm assuming) If I use these values the code fails with either a 'Win32 error' or a 'Generic GDI+' error depending on the exact value I increase to. I can usually get away with 9000 x 9000 but I have no control over the original tile sizes and so must work in multiples of 4000. It appears not to matter which type of control I try and load the tiles into, a plain form, a picture box, or a modified version of the excellent image viewer designed by one of the contributors to this site. They all fail if the background image is increased in size to 12000 x 12000. If any can shed any light on where I'm going wrong.....
Thanks in anticipation.
Rob Brookes
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Rob Brookes wrote: They all fail if the background image is increased in size to 12000 x 12000. If any can shed any light on where I'm going wrong.....
GDI won't hanlde an image that large (12000*12000*4 bytes per pixle = 576MB) and that doesn't account for the source images your using to build the single ackground image. The answer is you can't use an image that large, nor should you be using a control to do the drawing for you. You're going to have to make your map by drawing it to the screen yourself, handling scrolling and redrawing from your original source images with your own code.
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Very many thanks for the reply Dave, I'd largely come to that conclusion unfortunately. I've had a partial success by re-scaling the map tiles, as they're loaded, to 3000 x 3000 which works with no noticable effect on the performance of the program. I lose some map resolution but can probably live with that. My coding ability doesn't allow me to draw directly to the screen as yet but I'm working on it. Normally the program dynamically loads the map it needs as a position report is received by the radios but I'm limited to the area covered by the map tiles that way. If a plot appears on the extreme edge of one tile, the program stutters somewhat as it can't decide which tile to load hence I need to buffer the edges of each tile, and one in the centre with another 8 in the wings seemed the most obvious way of doing it. Understandable information on VB.net graphics handling seems a bit thin on the ground. If you can recommend anything to read, I'd much appreciate that.
Regards
Rob
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This is the VB.Net forum.
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I want to develop scientific calender control for window application
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So, what is your question?
Shay Noy
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VERY GOOD
Piyush Vardhan Singh
p_vardhan14@rediffmail.com
http://holyschoolofvaranasi.blogspot.com
http://holytravelsofvaranasi.blogspot.com
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I presently have a class which inherits another class, thus allowing methods and properties of the base class to be used as though they were properties of the inheriting class. Although that reduced typing when I was making the class itself, I've since decided I don't particularly like the design since operations that make sense applied to the base class don't necessarily make sense applied to the inheriting one, and even those that do would be more meaningfully applicable to the object within the inheriting class rather than to the inheriting class object itself.
If all references to the underlying base class were preceded by "mybase." there would be no particular difficulty changing the class to use a wrapper. All I'd have to do would be to define a new object of the inner type within the outer class, create it within the outer class' constructor, and then find/replace "mybase" with the name of that new object.
Is there any practical way to have VB stick "mybase." in front of all inherited properties and methods, or assist with the conversion in some other way?
One of my goals with switching from inheritance to wrapper is to allow the use of something like:
wrapperObject.thing = factoryFunction(someOtherThing)
This sort of scenario really doesn't work if 'thing' is inherited, since wrapperObject.myBase is a read-only property.
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