|
from Visudalstudio, Array.Clone reads: Creates a shallow copy of a array
but from the following simple test code, the results (a[0]=0 for two messagebox shows) show that Array.Clone is a deep copy (or else, the second output should be 100, because a and b refere to the same memory), how to understand it? thanks.
int [] a = new int [1];
a[0] = 0;
MessageBox.Show(a[0].ToString());
int[] b = new int[1];
b =(int []) a.Clone();
b[0] = 100;
MessageBox.Show(a[0].ToString());
|
|
|
|
|
Hi,
a shallow copy copies everything at the first level, values get copied (what else could one do?) and references get copied (not cloned).
in your code, b is a new array which first holds a zero (cloned from a), then gets overwritten explicitly, and then you show a[0]???
Luc Pattyn [Forum Guidelines] [My Articles]
The quality and detail of your question reflects on the effectiveness of the help you are likely to get.
Show formatted code inside PRE tags, and give clear symptoms when describing a problem.
|
|
|
|
|
I think I am not so clear about shallow copy and deep copy.
it seems to me that shallow copy and deep copy are sometimes same but sometimes are different.
for value copy, are the same?
for reference copy, they are different.
copy of an int array belong to value copy?, but array variable belong to a reference type.
I think that copy of an int array is a reference copy, therefore, I think for shallow copy, it copies only refrence. later, I found that copy of an int array belong to value copy!
|
|
|
|
|
Hi,
a shallow copy copies value types and references; so all data is the same as the original, but no new objects got created except for the one class instance copied.
a deep copy copies value types and clones referenced objects; so all data is the same as the original, AND new objects got created every time there was a reference.
an array is a reference type.
when the array elements are value types (e.g. int[]) a shallow copya and a deep copy do the same: all values are copied in the new array;
when the array elements are objects (e.g. Control[]) a shallow copy just copies all references, a deep copy clones all referenced objects.
In another way: a shallow copy can be implemented as a memcpy(), copying bytes without knowing the types of the data copied; a deep copy needs to know whether the members are values or references.
Luc Pattyn [Forum Guidelines] [My Articles]
The quality and detail of your question reflects on the effectiveness of the help you are likely to get.
Show formatted code inside PRE tags, and give clear symptoms when describing a problem.
|
|
|
|
|
|
Why is your example showing the value of a[0] twice?? You're never showing the value of b[0].
|
|
|
|
|
yes, I want to show a[0] twice in order to check whether the change of b[0] results in also the change of a[0].
|
|
|
|
|
I have a .NET application which is using the Microsoft.mshtml PIA. It frequently experienced exceptions with a message saying that the Microsoft.mshtml assembly or one of its dependencies is missing. Weirdly enough, this happens on some machines, but works fine on others! (actually, it works fine on the majority of machines)
I have tried to resolve this problem by adding PIA as private assembly but problem was not resolved.
then I have installed Microsoft.mshtml PIA in client's machienes GAC through installer. But not working.
I am not getting why this dll is not working as private assembly.
I am getting following Error message:
"Error unable to cas COM object of type 'System._ComObject' to class type 'mshtml.HTMLSelectElementClass'.
components that enter the CLR and do not suppor IProvideClassInfo or that do not have any interop assembly registered will be wrappen in the_
ComObject type. Instances of this type cannot be cast to any other class; however they can be cast to interfaces as long as the underlying COM
component supports QueryInterface calls for the IID of the interface."
Thanks for helps,
Manoj
|
|
|
|
|
That error means that the machine in question doesn't have the COM-based mshtml library installed that your code is using, or has an older version that your code doesn't support. I'd start by checking which version(s) of IE are installed on the machines that work and what version(s) are installed on the machines that don't.
|
|
|
|
|
It is working on IE Version: 6.0.2900.2180.xpsp_sp2_gdr.070227-2254.
But not working on IE Version: 6.0.2900.2180.xpsp_sp2_gdr.090206-1233.
How Can I fix this problem. 
|
|
|
|
|
Either reintall IE6, or upgrade the machines to IE7 or 8.
|
|
|
|
|
Hi,
can anybody help me regarding,
creating the notepad application with keyboard shortcuts for copy,cut,paste.....etc..in C#.Net
|
|
|
|
|
A TextBox already has those keyboard shortcuts built in. You don't need to add anything extra. Besides that, a notepad application is relatively simple. Try coding it yourself, and posting when you would like help with specific problems
Between the idea
And the reality
Between the motion
And the act
Falls the Shadow
|
|
|
|
|
So what's the question?? You haven't asked about any kind of a problem you're having...
|
|
|
|
|
He forgot to ask for the code. This is a first, someone failing at failing.
|
|
|
|
|
I cannot get the System.Net.Mail to send out an email message from my Windows application. The Try Catch reports an the error message 'Failure sending message'. What is causing the error? Below is the code I'm using.
MailAddress objFromMailAddress = new MailAddress("myfromemail@mydomain.com, "");
MailAddress objToMailAddress = new MailAddress("mytoemail@mydomain.com");
MailMessage objMailMessage = new MailMessage(objFromMailAddress, objToMailAddress);
SmtpClient objSmtpClient = new SmtpClient();
objMailMessage.Subject = "Subject line";
objMailMessage.IsBodyHtml = false;
objMailMessage.Body = "Body message";
objSmtpClient.Host = "1and1.com;
objSmtpClient.Port = 587;
try
{
objSmtpClient.Send(objMailMessage);
}
catch (Exception pError)
{
}
|
|
|
|
|
Probably because the host name is bad. You just supplied 1and1.com which is a domain name, but no host. You have to supply the full name of the server, like "smtp.1and1.com" or its IP address.
|
|
|
|
|
Thanks.
I've already tried smtp.1and1.com and could not get it to work.
I will try the IP address.
|
|
|
|
|
Come on. This is where you contact the ISP supplying the SMTP server and get its DNS name, the port number you have to use, and any login information you need.
|
|
|
|
|
You also never set credentials to authenticate yourself with your smtp host.
|
|
|
|
|
hello,
I've wrote an application that connects to mysql DataBase.
The DataBase updates every few minutes with new data,
when the user open the app he has few options to read the data (through ODBC).
when the users install the app on his locall computer,
does he also needs to install ODBC?
(The DB is located on a server and all the users that use the app are in the same network).
Thanks,
Tamir.
|
|
|
|
|
I do not know for sure, but I suspect that they will have to.
The easiest way to check would be to do a test install on one of the user computers without installing ODBC, make sure to select a computer that doesn't already have ODBC. If it works, the users don't need ODBC. If it doesn't work, install ODBC. If it still doesn't work, then something else is wrong.
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.”
|
|
|
|
|
Can i include the ODBC installation inside the install file that i create?
|
|
|
|
|
You need to install ODBC Only if the app is connected directly to MySQL DataBase. If Server has a service witch will act as a bridge and app connects to it then you dont need ODBC drivers installed anywhere else.
treuveni wrote: Can i include the ODBC installation inside the install file that i create?
Depends on Licence. One whay is to include ODBC Installation (External Execution like when installing Games then DirectX) within your own, or if you have permision you can include within your installer as in no seperate instalation
|
|
|
|
|
Yes, it is as simple as that..
How would you hide the form as soon as it's loaded assuming it's a one-form project "no splash screen"
You cant set the Visible property to false or call the Hide function on the form Load event.
A stupid way to do it was to:
1. set the ShowInTaskbar property to false
2. Set the opacity to 0
3. Call the hide method on the Shown event and maybe set back the above two properties to true and 1 respectively
But I dont want to do that since low graphics screen would treat 0 opacity as black square and the hiding the form on the shown event is not quite practical since the form gets loaded once but shown every time you want it visible.
Please advise!
All generalizations are wrong, including this one!
(\ /)
(O.o)
(><)
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
