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Ooooh, now I understand what you are doing.
I believe you will have change you logic a little. The DBNull is only a database value. I believe if you change the code to the following this should solve you problem.
DataSet Lds;
SqlDataAdapter Lda;
SqlCommandBuilder Lcb;
object[] LaobjValues;
string LstrQueryString;
using (SqlConnection Lconn = new SqlConnection(@"Data Source=.\DA;Database=Testing;Integrated Security=SSPI"))
{
Lconn.Open();
LaobjValues = new object[2];
LaobjValues[0] = "5";
LaobjValues[1] = DBNull.Value;
LstrQueryString = "Select TOP 0 * From Table1";
Lds = new DataSet();
Lda = new SqlDataAdapter(LstrQueryString, Lconn);
Lcb = new SqlCommandBuilder(Lda);
Lda.Fill(Lds);
Lds.Tables[0].Rows.Add(LaobjValues[0], LaobjValues[1]);
Lda.Update(Lds);
}
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thax for reply.
i done like what u have said. but now it is giving
error as object required. (rutime error '424')
thanx
raj
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I'm looking for a grid in Windows.Form to display some data stored in RAM (arrays, collection, ...) and not in a database.
Reading the DataGrid documentation seems that it display only data stored in a database or in a XML file.
Is there a grid to do this  ?
I'm using C# in Visual Studio 2003 and Framework 1.1.
nikolag
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You can bind the DataGrid to various differnt sources including arrays/collections/etc.
You can also use ListView to display items in a grid. Use myListView.Items.Add(new ListViewItem(new string[] {"Value1","Value2"}));
Make sure you've added appropriate columns to the list view. Checkout the "Columns" property.
- Malhar
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ok, the Microsoft documentation is not clear on this point  .
Thank you for your help  .
nikolag
"Tutti sanno che una cosa è impossibile da realizzare, finchè non arriva uno sprovveduto che non lo sa e la inventa"
(Albert Einstein)
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I am looking for a short overview explanation of 1.1 vs 2.9 .NET differences. I realize there is the What's New in the .NET Framework Version 2.0 http://msdn2.microsoft.com/t357fb32.aspx[^]
But.... is there something a bit shorter that gives the major differences? I was thinking I could take the "What's New in the .NET Framework Version 2.0" and try to shorten it up. But maybe there is something out there already that gives a very quick summary? I am really looking for something that will allow me to still use old .NET framework documentation (hard-copy books ), and then have something to refer to to make sure any older documentation that I am reading is not too out-of-date.
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LuluSailor wrote: I am looking for a short overview explanation of 1.1 vs 2.9 .NET differences. I realize there is the What's New in the .NET Framework Version 2.0 http://msdn2.microsoft.com/t357fb32.aspx[^]
That IS the summary version. There are over 200 new classes, 2,000 new methods, and some 1,200 changes to existing methods and properties. There's just no way you're going to be able to just "refer to the things that changed documentation" because the changes are in every corner of the Framework. I think your best shot is to just refer to the documentation for classes that you would be using and seeing what's changed and what's new.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Oh so very interesting! It looks like the summary is about 9-10 pages. ( I did copy the summary document and make it into outline format so I can see the main topic areas of change - see below). This might help a bit, but of course seeing just ADO.NET for example is not that helpful. I suppose as I go along I will start to see what changes are that significant over 1.1?
Main topics of change from the Microsoft document called "What’s new in the .NET Framework Version 2.0"
64-Bit Platform Support
Access Control List Support
ADO.NET
ASP.NET
Authenticated Streams
COM Interop Services Enhancements
Console Class Additions
Data Protection API
Debugger Display Attributes
Detecting Changes in Network Connectivity
Distributed Computing
EventLog Enhancements
Expanded Certificate Management
FTP Support
Generics and Generic Collections
Globalization
I/O Enhancements
Manifest-Based Activation
.NET Framework Remoting
Obtaining Information About Local Computer Network Configuration and Usage
Ping
Processing HTTP Requests from Within Applications
Programmatic Control of Caching
Programming Languages
Security Exceptions
Serial I/O Device Support
Serialization
SMTP Support
Strongly Typed Resource Support
Threading Improvements
Trace Data Filtering
Transactions
Web Services
Windows Forms–Related Features
XML-Related Features
-- modified at 22:10 Tuesday 31st January, 2006
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dear all,
i want to copy a file from server to localhost.in server my file is located in"D:\folder\myfile.txt".i want to copy/save that file int my localhost in"D:\myfile.txt".how can i do this using vb.net?please give me the code as soon as possible...
by
barani
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Here is fast and dirty solution
<br />
using System.Net;<br />
<br />
...<br />
...<br />
<br />
<br />
WebClient webClient = new WebClient();<br />
webClient.DownloadFile( "http://remotyeserver/myfile.txt", @"d:\myfile.txt" );<br />
Do the same using ftp is more complicated - but this ftp library[^] can help
DevIntelligence.com - My blog for .Net Developers
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Hello,
Is there any help available for SPRIN .NET Framework ?
Pankaj Kulkarni
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I assume you're talking about the Spring.NET Application Framework.
Try their Support Forums[^].
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Hello,
I am working on a project that requires me to generate long reports that can have 150 pages or more - Each of these pages are generated as an A4 image (~3500x2480pixels), which is then inserted into an ArrayList...
The problem however is that I'm repeatedly getting OutOfMemory exceptions that I seem to be unable to get rid of despite extensively clearing all objects i'm not using (using the Image.Dispose() method for example) as well as forcing the garbage collector (GC.Collect()) every now and then...
I'm constructing each of these images in the 1bpp pixel format that would mean that each of these images would be ~1MB on average... For 200 images, this (crudely) corresponds to a 200MB ArrayList.. I agree this is a size larger than many RAMs, but shouldn't my computer be able use the pagefile (my pagefile is set to 512MB)??
Any one has any ideas on how I can get rid of, or even handle, these OutOfMemory exceptions??
Thanks,
Sarab
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How are you using the report when it's finished, as you create the pages as images? Do they really have to be images?
Do you really have to create all images at the same time? Is there no way of handling the data of the report in some other way, and generate each image when you need it?
You could convert each image into GIF or PNG format, that would substantially reduce the size without losing any information.
---
b { font-weight: normal; }
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If it were me, I'd try just saving each bitmap as it's created, and then just keeping an arraylist of filenames (files in a temporary location), accessing individual files as needed.
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Just tried this...
I write each image to disk after it is created, dispose it and force the garbage collector after every 20 images...
No success however; I keep the Windows Task Manager on during processing, and the page file size still continues to gradually increase till it hits the limit, and once again I get hit with OutofMemory exceptions, which only lead to more when handled...
Interestingly however, the moment the control comes out of the routine - the page file size immediately drops back to normal...
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Heritos is right. I would save the images to and only hold a reference to them.
sarabjs wrote: For 200 images, this (crudely) corresponds to a 200MB ArrayList.. I agree this is a size larger than many RAMs, but shouldn't my computer be able use the pagefile (my pagefile is set to 512MB)??
No. Because .Net will use much more memory, as the code is managed and everything is encapsulate in Objects.
I tried it with a 3D-scene of 100 MB and old C++ only needs a little bit more than 100 MB for the whole programm while .Net used more than 200 MB.
Another Point is the Garbage Collection, which isn't a real one. If you generate an object and drop it afterwards its hold in the memory quiet a time. So there are objects which aren't used anymore.
Greetings,
Ingo
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ihoecken wrote:
Another Point is the Garbage Collection, which isn't a real one. If you generate an object and drop it afterwards its hold in the memory quiet a time. So there are objects which aren't used anymore.
That's not an accurate statement, you appear to be laboring under one of two incorrect assumptions. .net's garbage collector is generational which means that it attempts to collect younger objects far more frequently than older ones. If memory is needed it will however collect the older generations.
Secondly when an object is GCed the memory is returned to the application stack/heap, not to the operating system. Standard c/c++ runtimes behave the same way because requesting/returning memory to the OS is an expensive operation. Consequently the task manager doesn't display the actual ammount of ram the program is using. This is more apparent in .net since it's runtime requests a larger default chunk size than standard C++ ones. Excess memory is returned if the OS asks for it (ie appB requests more than the OS has available so the OS asks other running apps if they can return thier excess), minimizing the app will also trigger this release under .net. IIRC it will eventually do this on it's own if it concludes it asked for more than it'll ever likely need. If the systems apps are using more total ram than is physically available, the excess will be parked on the swap file because of inactivity so while it may make the task manager numbers look scary it doesn't have a real effect on performance.
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A good garbage collection begins to release unused memory when there is time, .Net Garbage collections releases memory when memory is needed. So its much slower and sometimes such memory isn't released properly, even if the object isn't used any more.
Greetings,
Ingo
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The .NET GC is self-tuning. It runs on both a semi-regular (self-adusted) schedule and on-demand when either the applications calls for it or the operating system does and wants memory returned. Memory is never released "improperly" as you call it. The GC tries, and does a very good job, at keeping a resonably sized pool of memory available to the application for future allocations. Like I said, the GC is self-tuning and can only improve it's allocation strategy by over-estimating what it needs to start with then watching how your application allocates and releases memory.
But, yes, the GC is a bit lazy when application activity is low, and for good reason. In order for the GC to run, the threads of your application must be stopped before the collection takes place. This is because objects in memory can be moved by the GC to compact and defrag the heaps and pointers to those objects must be updated to reflect their new locations. This cannot be done while the code is still running! So, yeah, the GC tries to be as lazy as possible, giving your app more time to execute.
Garbage Collection and object allocation, when dealing with the Managed Heap, goes VERY, VERY fast. It slows down considerably if memory has to be allocated from the system first, adding it to the Managed Heap.
BTW, this is all documented on MSDN:
Programming for Garbage Collection[^]
Garbage Collection: Automatic Memory Management in the Microsoft .NET Framework[^]
Garbage Collection—Part 2: Automatic Memory Management in the Microsoft .NET Framework[^]
Improving .NET Application Performance and Scalability[^]
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Hi Sarab,
I think that your problem is regarding the number of handles you create!!! If you know, Windows restricts each process in creating handles. For example, it is 10,000 handles for XP. But my experience says that this equation is that straight forward!!! It is also dependent on the memory the process occupies and the number of GDI objects being created by your app.
To confirm this, try seeing the number of GDI objects and Handles being created by your app through the taskmanager->View->Select Columns... And if the number of Handles is going beyond 500 and GDI objects more than 300 or 400, then i think that you have located the problem!!!
Even i had a similar problem, but not yet found the solution as such!!! The work around which i did was not storing such a huge data in memory which creates lots of GDI objects!!!! Though im able to get control over it, i feel that this is not the correct solution to it!!!
Regards,
Rajesh
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Thanks folks!! I appreciate everyone's help...
Turns out, I didn't have to cross the Seven Seas:
I managed to solve the issue by explicitly disposing (Image.Dispose()) some images I was creating during processing... I used to think that .NET automatically clears the memory being held by an image object once all references to it are removed - Guess that isn't the case...
Learnt a lot from these discussions though - Thanks!
-- modified at 16:03 Friday 3rd February, 2006
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I have a .Net application which at one point repeats a task several times. Each time the task is performed, it pops up a progress window, updates the window while working, and then closes the window.
This should all work fine, but what I am finding is that if I have a loop that repeats the task 5 times, the progress windows get displayed and updated, but the screen doesn't seem to redraw the parent window after they are 'closed', thus it looks as though all windows remain open until the last task completes, at which point the screen redraws, and correctly see that all windows have been closed.
Is there a function that I can call to ensure that all window events take place and the screen redraws after each task completes? I have this problem in several spots where a parent window calls a computation intensive task, and then does not get redrawn correctly until the task ends.
Thanks in advance for any pointers,
Spencer
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If you call the Invalidate() method of the control which isn't redrawing properly, followed by Application.DoEvents(), this should force the control to process its pending events and redraw.
If you're doing process intensive stuff and dont want the application to lock up, then you might want to consider using a seperate thread.
Cheers,
Will H
-- modified at 10:41 Monday 30th January, 2006
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