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Hi All,
I have a application created in C# that is working 100% on my Windows 2000 Prof with no bugs at all.
I have installed it on a NT4 machine with SP6 and most things still work but I am getting a few bugs.
For example.
I have some code that must run when a dropdownlist is changed.
On NT4 if they select something in the dropdown everything works fine, but if they drop the list and then click somewhere else they get an application error.
I cannot replicate this problem on my Windows 2000 box?
Can someone let me know why this happens?
Thanks,
Gavin Mannion
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I can store some kind of datatbase in XML files.The question is here:
In what condition it is better to use XML and when should I use Access/SQLServer database?
Mazy
"So,so you think you can tell,
Heaven from Hell,
Blue skies from pain,...
How I wish,how I wish you were here."
Wish You Were Here-Pink Floyd-1975
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It is roughly the equivalent to ask if you should use a comma separated file or a database.
Let us compare the two file types:
The XML file would have the possibility of bearing the meta information itself, but it is up to the designer to give the tags some meaningfull names.
If you use a dtd for the xml file, you could put the meta information here, but again, it is up to the designer to do so.
At the risk og getting flamed: IMHO XML files are glorified comma separated files, and the serialization process compared to (almost every) dbms is slooow...
Databases on the other hand, are containers designed for their respective dbms'es to give a balanced performance of searching, inserting, deleting and serializing and they are built for handling VERY large amounts of data.
Internally they keep some basic indexes on the position of data, and in exchange for resources like disk space, you can ask for extra indexes to improve search speeds.
Conclusion: If you are in need of serializing SMALL data portions, like 1-2 MB, you could use an xml file. But if the data portion will grow virtually unlimited or you are doing a lot of insertions/deletes that causes serialization, then you should use a database (even Access is able to compete here).
Jan
"It could have been worse, it could have been ME!"
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hmmm,thanks ![Rose | [Rose]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/rose.gif)
Mazy
"So,so you think you can tell,
Heaven from Hell,
Blue skies from pain,...
How I wish,how I wish you were here."
Wish You Were Here-Pink Floyd-1975
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Hi everyone:
I will given a OMG idl file and wanna build a object tree according to it.
Is there any free or cheap tool to make me bind the idl to cpp or C#?
Thank you
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My select statement looks like this:
string str="select t1.amt,t2.Name,t3.Desc from t1 left join t2 on t2.ID=t1.ID left join t3 on t3.ID=t2.ID";
When I execute ExecuteReader() I' getting an error.
With only first join it's OK, with only second join it's OK but with joins there is exception.
Is this syntax incorrect for two joins?
Jerzy
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JerzyPeter wrote:
string str="select t1.amt,t2.Name,t3.Desc from t1 left join t2 on t2.ID=t1.ID left join t3 on t3.ID=t2.ID";
string str="select t1.amt,t2.Name,t3.Desc from (t1 left join t2 on t2.ID=t1.ID)left join t3 on t3.ID=t2.ID";;)
Best Regards
Carlos Antollini.
Sonork ID 100.10529 cantollini
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Thanks a lot!!!
Jerzy
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In terms of capabilities, they say VB.NET and C# is the same. So what about speed? Which is faster?
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neither is faster
both languages compile to the same IL, which runs at the same speed regardles of what language it was compiled in.
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thanks,
that makes sense.
But compared to both of them how fast is c++ (10 times faster? maybe?);)
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IL executes at roughly 80-90% the speed of C++ because it is native code, not interpreted like Java.
James
Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978
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Oh! This is driving me  . I have a windows service written in C# and .NET. All it has to do is write an xml document based on the information found in the system, for every 5 seconds. So I have a timer and a GetInfo function. This function is called by the Elapsed event of the timer (every 5 secs). And I have included everything in try...catch block. In my catch block, I catch any exception thrown and store in EventLog.
I am getting a lot of problems.
1. The service is not starting. When I start it using the Services Manager, it will attempt to start and end up saying "Service could not be started in a timely fashion".
2. In some test machines it starts although, its not writing any xml nor any EventLog Exception entry. I checked my code thoroughly and is just working ducky in my development machine.
Is there some security issue that I need to consider while running this service? (I am running the service as LocalSystem account). How would this affect accessing Eventlog or writing an xml doc...???
Any suggestions/..
omkamal
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Hi omkamal:
Well i am running thru the same scenerio my friend. I am logged in as Local Admin on my win 2000 prof box and installed a .net C# service as LocalSystem account. When I try to start the service it hangs on and gives me that standard error, that is, "Service could not be started in a timely fashion".
What all things do u need to take care or what are the prerequisites for a successful service install and start up? I even tried creating a basic service and tried starting it but gave me the same stupid error message!!
Thanks,
Rakesh
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Hi,
I am attempting to use declarative code access security to protect
my C# web application. I am using
[UrlCodeIdentityPermissionAttribute(SecurityAction.Demand, Url =
"http://www.microsoft.com")]
outside of the main class in my dll.
I understand that this means that if a website other than Microsoft
calls my dll code they should be refused access to the protected class
- an exception should be thrown. When I call my dll code from another
program, access is always granted.
Is my understanding of declarative code access security incorrect?
What am I doing wrong? Any help would be greatly received. I am new to
this area and am finding it difficult to find code examples of such
code. Examples of imperative security would also be useful
Thankyou,
Kerry
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I've spent a lot of time playing with my datagrid control and its associated datatable, and I think I did it all wrong. My scheme is way to complicated. I read a user defined data structure in from a file, then fill out the datagrid from it. Then I track any changes to the datagrid, update the datagrid to reflect these changes (these former two steps are giving me too much trouble, prolly b/c my overlycomplicated design), and then rebuild the structure from these changes. However, there seems to be some interdependencies in the updating of the datagrid that depends upon nonupdated information in the data structure, and it's all a big mess. 
My actual on-disk data format is XML, which is then parsed into the datastructure for program specific manipulations (calculating chess scores from a tournament database if you must know). I want my users to be able to create and edit chess tournament databases using this datagrid, which will then be mapped into the in-memory data structure for the calculation and manipulation, and finally saved to a disk in XML format. I have all the XML -> Datastructure and Datastructure -> XML stuff down, but the user input is really getting to me.
So, before I start with my datagrid all over again, I need to know how I'm supposed to do this. My current idea is:
+ Load the file into the data structure
+ Update the datagrid/datatable (I am using them as one, there's only one table).
+ Use the RowChanged event to determine when the datagrid is modified. If so, make those changes INSIDE THE DATA STRUCTURE. Then, after the datastructure is updated, set a flag so that RowChanged does nothing, and rebuild the datagrid from the beginning using the data structure. After it is rebuilt, set the RowChanged flag back so that it responds to user input. I want RowChanged to respond to userinput, but not to respond to itself. I will know this all works when I can throw any valid input into it, and get the same thing out, only now stored in the data structure. When I throw in invalid or incomplete (ie, half a row) input, it should not parse it at all, simply leave it there.
Sound good? There must be a standard way of doing this. I am completely new to all this database stuff.
-Domenic Denicola- [CPUA 0x1337]
MadHamster Creations
"I was born human. But this was an accident of fate - a condition merely of time and place. I believe it's something we have the power to change..."
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I think the recommended way of working with data is through the DataSet.
You can load a dataset from xml (create a schema then specify where to load it from an the schema), then bind the dataset to the datagrid, once you are done editing you should then be able to save the data back to the xml file.
DataSets are a bit mysterious to me though; most of my data access has only been single read/writes so I've not had to worry about that yet
James
Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978
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A dataset seems to just be a collection of datatables that relate to each other. I only use one data table, and I only want to use it for display and user input purposes. My custom data structure is the best way of storing and manipulating my data, everything is organized for maximum usefulness from the programming side of view. I would like to use the datagrid as a method of directly editing and creating those data structures.
What I am trying to say is, this program is primarily a computation program, not a database program. I have all the code for computation on my data structure and loading into my data structure. I simply want a viable way to display all this data both before and after computation, and also to edit and create new data. DataGrids looked like the solution to my problem, but I dunno, maybe I've stepped too far into the realm of database programming by using them. I JUST WANT USERS TO BE ABLE TO SEE, EDIT, AND CREATE DATA IN A GRID-LIKE FORMAT. I don't want to run a commercial database, or use ADO.NET, or generally have anything to do with the conventional meaning of "database".
Does that help clarify my problem? It is all very confusing, and hard to explain. Sorry if I've just made it worse.
-Domenic Denicola- [CPUA 0x1337]
MadHamster Creations
"I was born human. But this was an accident of fate - a condition merely of time and place. I believe it's something we have the power to change..."
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[edit] bah after re-reading your original post I see I haven't posted anything helpful About the best I can offer would be to let the grid do its job, then when you need the data, pull it from the datagrid all at once (or do it when you add/edit a row). [/edit]
Domenic [CPUA 0x1337] wrote:
A dataset seems to just be a collection of datatables that relate to each other. I only use one data table, and I only want to use it for display and user input purposes.
The power of the dataset is its disconnected nature. The data stored in it is just that data; it doesn't have to come from a database at all. That is one of the strengths of .NET, it uses generic binding rather than forcing the use of ADO.NET or anyother database type technology.
Domenic [CPUA 0x1337] wrote:
DataGrids looked like the solution to my problem, but I dunno, maybe I've stepped too far into the realm of database programming by using them.
After some playing around I think you can do what you need to with a single DataTable (as I think you originally suggested).
Handling the ColumnChanging event lets you determine if a change should be allowed (if you don't want to allow the change throw an exception in the event handler).
Unfortunately I don't see an event that tells you when a new row gets added (and accepted) so you may have a hard time to keep the two in synch at all times but so long as you know when it does/doesn't need to be in synch you can do so by going through the datarow collection on the table.
Thanks for giving me the push to take a deeper look into DataGrids and DataTables
James
Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978
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James T. Johnson wrote:
Handling the ColumnChanging event lets you determine if a change should be allowed (if you don't want to allow the change throw an exception in the event handler).
Ahhh, so that's what's happening to my current code. It seems after I handle a deletion of a value, whenever I call DataTable.Columns.Remove(...) to reflect the invalidation of the row and update the columns accordingly, my ColumnChanged event handler is never called again. Ah, my code is way too messy anyway, it's prolly a good thing I'm redoing it.
So, does this sound like a good plan? I just iterate through the rows every time columnchanging is called, determine the valid ones, rebuild my data structure using those, and then rebuild my datagrid from my datastructure.
And how to decide between ColumnChanged and ColumnChanging? It seems ColumnChanged is called everytime the cursor moves out of the box or the data is otherwise accepted, which seems more appropriate than ColumnChanging, which is called whenever the column's value changes at all. I dunno, I'll work on it on the weekend when all this homework slows down 
-Domenic Denicola- [CPUA 0x1337]
MadHamster Creations
"I was born human. But this was an accident of fate - a condition merely of time and place. I believe it's something we have the power to change..."
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Domenic [CPUA 0x1337] wrote:
Ah, my code is way too messy anyway, it's prolly a good thing I'm redoing it.
If its too messy its probably a good idea Personally I find myself redoing lots of code because it becomes difficult to discern what is going on.
Domenic [CPUA 0x1337] wrote:
So, does this sound like a good plan? I just iterate through the rows every time columnchanging is called, determine the valid ones, rebuild my data structure using those, and then rebuild my datagrid from my datastructure.
Without knowing whats going on its hard to say what would be best. From what I know I would let the datatable do its job then pull the data out of it only when its needed. Handling the ColumnChanging/ColumnChanged events as needed for validation; then run a final validation with the RowChanging event to ensure that fields within a row are ok.
Domenic [CPUA 0x1337] wrote:
And how to decide between ColumnChanged and ColumnChanging?
Here's a quote from the documentation.
The ColumnChanging, RowChanging, and RowDeleting events are raised during the update process. You can use these events to validate data or perform other types of processing. Because the updates are in process during these events, you can cancel the update by throwing an exception, which prevents the change from being completed. For more information, see Data Validation in Datasets.
The ColumnChanged, RowChanged, and RowDeleted events are notification events that are raised when the update has been completed successfully. These events are useful when you want to take further action based on a successful update.
Hopefully you can get some idea where to go from here
James
Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978
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How to solve "System.StackOverflowException"
I am getting this, when I try to set a value to memeber variable.
namespace StackOverFLow
{
/// <summary>
/// Summary description for Class1.
/// </summary>
class StFlow
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
StFlow STF = new StFlow();
STF.Name = "CodeProject";
string str = STF.Name;
}
public string Name
{
get
{
return Name;
}
set
{
Name = value;
}
}
}
}
Thanks,
Candy
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The problem is caused because your property is trying to get/set itself. You need a private field to store the value, and the property gets/sets that.
private string name;
public string Name {
get {
return name;
}
set {
name = value;
}
}Notice the different in case between name and Name. C# is case sensitive
HTH,
James
Sonork ID: 100.11138 - Hasaki
"Smile your little smile, take some tea with me awhile.
And every day we'll turn another page.
Behind our glass we'll sit and look at our ever-open book,
One brown mouse sitting in a cage."
"One Brown Mouse" from Heavy Horses, Jethro Tull 1978
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Every time you access Name within your getter or setter code, you recursively invoking it. It stops only when this call sequence exhaust the call stack. You can check it tracing execution in debugger. There are to possible ways to correct this. First is to just create the field:
public string Name; // all problems gone
the second one is to back up your property with the private field and use in getter and setter code:
private string name; // lowercase n
public string Name
{
get { return name; } // you are noo more recursively accessing getter here
set { name = value; } // same for setter
}
Cheers,
elk.
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Hi! I'm going to serialize/save an object into a MS SQL Database ... but how?
Hope anybody can help me!!
/Kenneth
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