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If you google for 'age calculation c#' you will get several pages of hits. Some are more accurate than others, but they should give you some ideas at least.
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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others have given the answer already.
Schdev wrote: int ageYears=Datetime.Now.Year-datetimepicker1.Value.Year;
is plain wrong unless today is December 31.
Luc Pattyn [Forum Guidelines] [My Articles]
- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use the code block button (PRE tags) to preserve formatting when showing multi-line code snippets
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I have a fairly standard Form1.cs with a listbox to display comms traffic. The comms traffic comes from two different interfaces each of which is handled by it's own background thread. I want to log the traffic in the listbox on Form1 and have set up a delegate / Invoke routine as below in the Form1 class:
public delegate void LogDelegate(string s);
public void log(string message)
{
if (InvokeRequired)
{
Invoke(new LogDelegate(log), new object[] { message });
}
else
{
lb.Items.Add(message);
lb.TopIndex = lb.Items.Count - 1;
}
}
When I try to call log(string) from either of the backgound threads the compiler isn't finding this function and I cant for the life of me see why not. I did try making it a static but that threw lots of errors so I took that away.
What am I doing wrong please?
Many thanks, Bruce
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I suspect this problem has nothing to do with threads.
public void log( string message ) is a normal ( instance ) method in Form1 , so you need to call it using an instance: myForm1.log( message ) .
Nick
----------------------------------
Be excellent to each other
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Hi Nick, Thanks for your response. The thread will see Form1.log() if I make the log method a static. However if I make it a static the compiler kicks on just about every line of log() with "Object refernece required for ..." I just am not sure what it is looking for that I haven't provided.
Cheers, Bruce
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Assuming Form1 is your main form and you only have one instance of it, put this in Form1 :
static Form1 _Instance = null;
public Form1()
{
if ( _Instance != null ) [ throw an exception or assert or something ]
_Instance = this;
}
public static void LogMessage( string message )
{
_Instance.log( message );
}
Then use this from your threads:
Form1.LogMessage( message );
Nick
----------------------------------
Be excellent to each other
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Yep, that is why Nick said myForm1.log , not Form1.log.
myForm1 should be a variable pointing to your Form1 instance.
Luc Pattyn [Forum Guidelines] [My Articles]
- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use the code block button (PRE tags) to preserve formatting when showing multi-line code snippets
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Hi Bruce,
I think that the problem might be with the:
if (InvokeRequired)<br />
line. Try:
if (this.lb.InvokeRequired)<br />
and then
lb.BeginInvoke(new LogDelegate(log), new object[] { message });<br />
Hope this helps.
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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The Form and ListBox both run on the same ( UI ) thread, so it doesn't matter which you use.
Nick
----------------------------------
Be excellent to each other
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Yes, of course! How dumb.
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.
That is still throwing compile errors. I am beginning to suspect that the problem is because the two background threads are each in their own class file and that they cannot see the log(message) method in Form1 unless I make that method a static. Having made it a static the compiler is having trouble with pretty much every line of the method as follows:
Error 2 An object reference is required for the non-static field, method, or property 'System.Windows.Forms.Control.Invoke(System.Delegate, params object[])' \\Server1\srvr\Code\PC Programs\SYSTest\SYSTest\Form1.cs 60 17 SYSTest
Can anybody confirm whether I can make the log(message) a static or do I have to restructure my solution to put the background threads inside the Form1 class so I do not have to make the function into a static?
Many thanks for all your valuable input,
Bruce
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The two background threads certainly need to be able to 'see' Form1, the best bet is probably as Nick suggested by passing a reference to Form1 in the constructor of the threads.
The problems caused by making log() static are that log() itself will not be able to see the listbox.
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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"The problems caused by making log() static are that log() itself will not be able to see the listbox."
That makes sense. The compiler errors when the method is static could very well be caused by that.
I will try Nick's suggestion and let you know.
Many, many thanks
Bruce
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What is spawning the threads? If it's the same class then you shouldn't be having an issue. If it's a seperate class then the easiest way is to raise an event in that class, that the form can subscribe to, and in the handler invoke the method required.
DaveBTW, in software, hope and pray is not a viable strategy. (Luc Pattyn) Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia) Why are you using VB6? Do you hate yourself? (Christian Graus)
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Hi Bruce,
the code shown is perfect. However the problem is elsewhere. You have to help those threads to find and use your log method. Especially for logging purposes I tend to do that with static events, like so
(incomplete and unchecked code):
class Form1 : Form {
public Form() {
...
Class2.Logger+=log;
}
public void log(string s) {...}
}
and the "log clients" look like this:
class Class2 {
public static event Action<string> Logger;
private void log(string s) {
if (Logger!=null) Logger(s);
}
}
BTW: the event does not have to be static, but it allows for doing Logger+=log before the actual client objects have been created.
PS: I always like to have a log(Exception) method too; I either solve that by doing the above stuff twice, or by adding the following code in every log client class:
private void log(Exception exc) {
foreach(string s in exc.ToString().Split('\r','\n')) if (s.Length!=0) log(s);
}
Luc Pattyn [Forum Guidelines] [My Articles]
- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use the code block button (PRE tags) to preserve formatting when showing multi-line code snippets
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Don't want to hijack the thread but...
I experimented briefly with static events a while ago and came across a slight issue of objects not getting disposed.
Normally, if a ClassA instance subscribes to an event in a ClassB instance, when ClassB instance goes out of scope, it will allow ClassA instance to be disposed if there are no other references. With a static event in ClassB, that never happens of course and ClassA instance will continue to exist for the application's lifetime unless it explicitly unsubscribes from the static event.
Worth bearing in mind as otherwise unexpected things can happen, as well as potential memory pressures.
DaveBTW, in software, hope and pray is not a viable strategy. (Luc Pattyn) Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia) Why are you using VB6? Do you hate yourself? (Christian Graus)
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Hi Dave,
IMO your remark is perfectly valid in general; however in this situation the form implementing the log functionality is assumed to be the main form, and to live for as long as the app is running. If not, one should consider implementing the log server in a separate class, or drop the statics.
Luc Pattyn [Forum Guidelines] [My Articles]
- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use the code block button (PRE tags) to preserve formatting when showing multi-line code snippets
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in my app i writes to eventlog , but in some machines t get an exception (unhandled) saying that cannot write to eventlog, i think it is because of some privileges , i want to fix this how can i fx it, and how can i set the privileges programatically
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Hi I'm currently trying to dynamicly invoke each class, in a namespace. So far I have managed to take one class and illiterate through it's methods, properties, etc.. and return a collection of data that gets added to a dataset. However the adjacent classes in that namespace I also need to invoke dynamicly,
So far i've attempted this with Reflection as I did with the individual class, but at a namespace leave it seams I need a different approach
For the Record:
VS 2005 C# .NET 2.0
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hey all,
I created a shared addin project in visual studio 2005, an addin to excel that creates a button on the excel standard bar and assigns some event to it. Also, my addin acts an Automation addin. Now when I built the 'Setup project' of my addin, I got a setup file which I installed on a test machine. On this test machine, to my surprise, the addin's automation part is not working but the COM part is working fine i.e., the button is coming up on the standard bar.
The reason I found out for this is, the Programmable key word is not being added to the HKCR\CLSID\GUID\ of my addin in the test machine.
How to resolve this problem!? I want excel to recognise the UDFs i defined in my addin so that it also acts as an automation addin.
Regards.
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hello!
guys... isn't there anybody to discuss the problem and come up with atleast ideas to approach the solution?!
regards.
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Hi,
I need to create a session level connection object. The situation in like that, there can be multiple users loging in simultaneously. I need a different connection object for each user and want to maintain the count of the connection objects.
Platform: ASP.Net,C# 2005
Please help.
regards,
Abhishek agrawal
abhishek
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i know some english. i hope you understand me.
i developing a windows application with visual studio 2005.
i try changing comboBox font name in visual studio properties window. but font name not view all windows fonts(windows/fonts).
how to view all fonts in windows/fonts directory.
best regards
Tayfun ISTANBUL
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The Font dropdown in the properties window should show all installed fonts.
It is possible to have font files in the Fonts Directory that have not been installed.
So firstly, make sure that the font you are looking for has been installed. (Open the Fonts Directory in Explorer and right-click, just in case you don't know.)
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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How to do unit testing to non-function? I'm using vsts 2008 and i able to create a unit testing for function but i'm not sure how to create for sequential structure code.
plz help!
modified on Tuesday, April 7, 2009 10:16 PM
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