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his is the strangest thing I've ever seen. Why does 'ValueChanged' change the value ? How would someone looking at the API work this out ?
Christian
I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer
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 I was testing the values returned from a method and left that in by accident.
I agree, a method that checks if a property has changed should not change the property it was checking.
I have ammended the example as not to cause confusion.
Regards
Wayne Phipps
____________
Time is the greatest teacher... unfortunately, it kills all of its students
LearnVisualStudio.Net
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In that case I have several comments:
1. If I were to write this, I'd just do something like return(CurrentValue == theValue);, there's no need for a bool variable
2. If I did have to use a variable, I'd make sure it had a default value. In cases like this, I'd start with something like bool retVal = false;, and just set it to true if the test passed later
3. You seem to be asking if the current value != a specific value. I'd do this in the calling code: if (myClass.CurrentVale != theValue) instead of adding a method needlessly.
Christian
I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer
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Thanks for your comments, they all make sense.
However I wrote a simple method to demonstrate multiple and single exit points from the method not the simple evaluation of an integer.
Some methods become much more complicated when using nested if or switch statements and it appears very easy to end up with multiple exit points which make the method difficult to follow and debug.
I try to avoid this wherever possible but just wanted other opinions on best practices.
Regards
Wayne Phipps
____________
Time is the greatest teacher... unfortunately, it kills all of its students
LearnVisualStudio.Net
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OK, in that case, I'd always create the return value first, default it to the worst case scenario ( and never create a variable that I don't assign to ), and then I'd prefer switch to if statements where-ever possible, and if my switch statements are getting too big, think about if I can use OO or at least extra levels of call stack depth to factor some of that out.
Christian
I have several lifelong friends that are New Yorkers but I have always gravitated toward the weirdo's. - Richard Stringer
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HI.Can someone tell me where can I find the code of program which calculates angle between 2 vectors in 2D. Thanx in forward
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Who can tell you where to find stuff? Yahoo can[^] and Google can[^].
How hard is it to type "calculate angle between 2 vectors" in Yahoo or Google?
Long live ![Green Alien | [Alien]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/alien.gif) !
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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I have a utility that I wrote that performs a repair and compact on all the access databases in a particular directory. The problem I have is that I have 97 and 2003 databases in the same folder. If I use "Jet OLEDB:Engine Type=5" on the older access 97 files they are unreadable afterword. But if I use "Jet OLEDB:Engine Type=4" to work with the 97 files it blows up on the 2003 files. I would assume that someting like determining if a database is access 97 or 2003 would be simple but I'm finding it increasingly dificult to track down. I can do a "select version" against access 2003 and it gives me the version but the same command dosent exist in 97. I dont want to assume a database is 97 because the command fails. Any assistance on this would be greatly appriceated. Thanks.
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From a very old VB6 utility of the same nature:
I would expect that you could do the same with the OleDbConnection object in .Net, but haven't tried it.
Dim Con As New ADODB.Connection<br />
Dim p As Variant<br />
Con.Open "Provider= Microsoft.Jet.OLEDB.4.0;Data Source=" & src & ";User Id = admin; Password =;"<br />
p = Con.Properties("Jet OLEDB:Engine Type")<br />
Con.Close<br />
Set Con = Nothing<br />
If p = 4 Then<br />
DbEngine.CompactDatabase "Jet OLEDB:Engine Type = 4;Data Source=" & src, "Jet OLEDB:Engine Type = 4;Data Source=" & dest<br />
Else<br />
DbEngine.CompactDatabase "Data Source=" & src, "Data Source=" & dest<br />
End If<br />
'
Anger is the most impotent of passions. It effects nothing it goes about, and hurts the one who is possessed by it more than the one against whom it is directed.
Carl Sandburg
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Hi!
I have some problems reading an XML file with the following code:
--------------
XPathDocument oDoc = new XPathDocument(sXmlFilePath);
XPathNavigator oNavigator = oDoc.CreateNavigator();
XPathNodeIterator oIterator = oNavigator.Select("/pages/page");
if(oIterator.Count == 0)
return;
while(oIterator.MoveNext()) {
//read through the pages
}
-------------
The code works with the following XML:
<?xml version="1.0" encoding="utf-8" ?>
<pages>
<page name-fr="Niveaux" name-en="Levels">
...
</page>
</pages>
But fails with:
<?xml version="1.0" encoding="utf-8" ?>
<pages xmlns="http://tempuri.org/ConfigStructure2.xsd">
<page name-fr="Niveaux" name-en="Levels">
...
</page>
</pages>
Because of the xmlns.
What is the syntax in my "Select" to make sure I don't care about what the xmlns is and go directly to iterate though the pages? Is there another way to skip directly to the "page" nodes?
Thanks!
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IIRC it doesnt work on the default namespace. The trick was to add the namespace with an alias to an XmlNamespaceManager object and pass that to the SelectXXX or XPath methods. Note, you need to prepend the namespace alias in your query.
HTH 
top secret
Download xacc-ide 0.0.3 now!
See some screenshots
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Hi everyone:
I wanted to know what the best way to do this is. I basically have a program that I have made in C#. Requests will be made of this program by sending messages to an MSMQ queue.
Triggers have two things they can invoke, and programs can monitor queues so, I see three ways that this can be done:
1) Invoke an exe as a trigger action that I have programmed (this didn't seem like a good idea)
2) Monitor the queue with a windows service and asynchronously process it (I didn't see anything wrong with this)
3) Invoke a COM object on access.
The third option seemed like the best one for me, but I didn't know how to go about creating a COM object from C# or if it was even possible! Does anyone know if such a thing can be done or whether I should or shouldn't do it?
Thanks a lot!
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I am relatively new to the C# language and need to extract data from a text file. I would like to be able to search the file which is tab delimmited and extract various fields. I have been using StreamReader to read the file but I am not sure of the method that actually searches for relevant fields and then extracts them.
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Are you looking specifically on ways to parse the data once you have read it from the file? Specifically you could look into using regular expressions within .NET as a parsing mechanism. Check out the documentation .NET Framework Regular Expressions[^] from .NET Framework Developer's Guide.
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Thankyou, I will have a read of the documentation. I basically have a text file full of results in rows and columns. The idea is that the user selects the results that need to be viewed and they are extracted from the file.
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You could always use ADO.
Heres an example in VB.Net that I found usefull:
http://www.dotnetspider.com/technology/KBPages/890.aspx[^]
It allows sql queries to be performed against the csv file. You can even perform joins to other csv files in the same directory.
I believe you will have to create a Schema.ini file if you file is tab delimited.
Hope this helps.
Regards
Wayne Phipps
____________
Time is the greatest teacher... unfortunately, it kills all of its students
LearnVisualStudio.Net
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Hi,
I am trying to create an enhanced metafile that draws several retangles. I want the rectangles to have physical dimensions in mm, so that they will be cut by a laser engraver in these units. The code below attempts to create an EMF with a single rectange 100mm by 100mm, but when I open it in Corel Draw, it says the rectangle is only 94.5mm by 88.6mm. Can anyone explain this disparity to me?
public Form1()
{
//
// Required for Windows Form Designer support
//
InitializeComponent();
//
// TODO: Add any constructor code after InitializeComponent call
//
// Create temporary Graphics object for metafile
// creation and get handle to its device context.
Graphics newGraphics = this.CreateGraphics();
IntPtr hdc = newGraphics.GetHdc();
// Create metafile object to record.
Metafile metaFile1 = new Metafile("SampMeta.emf", hdc);
// Create graphics object to record metaFile.
Graphics metaGraphics = Graphics.FromImage(metaFile1);
//Set the graphics unit to mm
metaGraphics.PageUnit = GraphicsUnit.Millimeter;
// Draw rectangle in metaFile.
metaGraphics.DrawRectangle(new Pen(Color.Black, 5), 0, 0, 100, 100);
// Create comment and add to metaFile.
byte[] metaComment = {(byte)'T', (byte)'e', (byte)'s', (byte)'t'};
metaGraphics.AddMetafileComment(metaComment);
// Dispose of graphics object.
metaGraphics.Dispose();
// Dispose of metafile.
metaFile1.Dispose();
// Release handle to temporary device context.
newGraphics.ReleaseHdc(hdc);
// Dispose of scratch graphics object.
newGraphics.Dispose();
}
J Adam Crain
UNC-CH Department of Physics and Astronomy
crain@physics.unc.edu
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is it possible to separate each for separatly to avoid sending the whole application each time to the customer whe I update just a simple text in one form?
how?
many thanks....
Jassim Rahma
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jrahma wrote:
is it possible to separate each for separatly to avoid sending the whole application each time to the customer whe I update just a simple text in one form?
Yes, you could feasibly build each individual form into their own assembly, however you could also consider using the localization support in .NET and keep that as a separate assembly, thus allowing you to simply distribute that alone. If you are interested in checking out the localization support for .NET I would recommend you read Resources and Localization Using the .NET Framework SDK[^] and Resources in Applications[^] from the .NET Framework tutorial and developers guide.
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Now I am stumped! I have worked out how to talk to an ASCII printer over a COM port (using system APIs), but how do I talk to an ASCII printer that is hanging on an USB port?
Assuming somebody has an elegant answer to this, will this also work for .NET Compact Framework?
Peter Beedell
"Remember that age and treachery will always triumph over youth and ability." Quoted from the BBC Comedy 'The Office'.
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You'll need a .DLL to handle communication with the USB printer for your app. There is no ".NET way" of doing this.
Try searching the web for "Raw USB printer" or something like that, or, if your proficient with C++ and writing lower level USB device drivers, you can try writing it yourself.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Hi,
I am writing a debugger and I am trying to implement a multi column TreeView for showing the local variabls (such as in visual .Net).
How can I implement it or maybe such implementation already exists as open source?
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Have a look at:
http://www.codeproject.com/cs/miscctrl/treelistview.asp
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I've got an ASP.NET application written in C# which uses an Access database. Sometimes, when several users try to access the application at the same time, a "file is opened exclusively by another user" exception is thrown.
AFAIK, I need to synchronize access to the database. I've got a single place where all database access (like read a dataset, executenonquery) methods are. I tried using a ManualResetEvent to perform the task, but the problem is still there.
Can anyone recommend an approach?
Regards,
Serge
my blog on Easy Projects .NET and object-relational mapping
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To handle multiple users, the Jet database engine has to be able to create a .ldb file (i.e. if your database is called MyDatabase.mdb, it has to create MyDatabase.ldb). Check that the user account your ASP.NET process runs under can create files in the same directory as the .mdb. If Windows 2000 or XP, by default it's ASPNET, while on Windows Server 2003 it's NETWORK SERVICE.
Stability. What an interesting concept. -- Chris Maunder
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