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well sir sure i like to take urs help...i have just reaced to my destiny as well but some problems occuring in it.....
i m writing here u code and plz try to help me...The problem occuring on following places..please read code i m writing where the problem is occuring..
///////////////////////////////////////////////////////////////////
try
{
PropertyDataCollection __gc *pdc = e->NewEvent->get_Properties();
PropertyDataCollection::PropertyDataEnumerator __gc *pdce = pdc->GetEnumerator();
while(pdce->MoveNext())
{
PropertyData __gc *pd = pdce->get_Current();
ManagementBaseObject __gc *mbo = dynamic_cast<managementbaseobject *="">(pd->get_Value());
1) problem***************problem occuring on the below if statement.not all time but some time the mbo variable does not declare and by using watches i see that mbo is undeclared value.its some time ... and printer does not pause..***********************************
if( mbo != NULL && mbo->ClassPath->ToString()->ToUpper()->EndsWith(S"WIN32_PRINTJOB") )
{
/////
//pause job
long a=0;
long *hprinter = &a;
for(int i=0 ; i<this->printersname->Length ; i++)
{
try
{
int result = PrinterAPIs::OpenPrinter(this->printersname[i], hprinter, NULL);
bool resultf = PrinterAPIs::SetJob(*hprinter, (long)Int64::Parse( mbo->Properties->get_Item(S"Jobid")->Value->ToString() ), 0, NULL, 1);
PrinterAPIs::ClosePrinter(*hprinter);
MessageBox::Show(this, mbo->Properties->get_Item(S"Owner")->Value->ToString());
*****************************************************************************
2) Below message box is not showing the correct number of pages that comes from print status that come in task bar when a pages are going to print.***************************************
MessageBox::Show(this, mbo->Properties->get_Item(S"TotalPages")->Value->ToString());
if(resultf == true)
break;
}
catch(Exception __gc *ex)
{
MessageBox::Show(this, ex->ToString());
ex = NULL;
}
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You do realize this is the C# forum, right? Visual C++ is over here[^]!!
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Hello,
I'm absolutely new to programming, so please don't be too hard on me...
I'm trying to make a simple form application to hide or show hidden files. When I try to run the application I get a "System.NullReferenceException: Object reference not set to an instance of an object."
I found many topics related to this problem, but I still cannot figure it out.
Here's the code:
partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void HideFiles()
{
RegistryKey MyKey = Registry.CurrentUser;
MyKey = MyKey.OpenSubKey(".Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced", true);
MyKey.SetValue("Hidden",2);
MyKey.Close();
}
private void ShowFiles()
{
RegistryKey MyKey;
MyKey = Registry.CurrentUser;
MyKey = MyKey.OpenSubKey(".Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced", true);
MyKey.SetValue("Hidden",1);
MyKey.Close();
}
private void ShowButton_Click(object sender, EventArgs e)
{
ShowFiles();
}
private void HideButton_Click(object sender, EventArgs e)
{
HideFiles();
}
}
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NullReferenceException is a very basic exception you get when you declare an object reference but do not assign a value to it (or, in your case, have a method returning null and assigning this null to your reference) and then try to access the non-existing object.
Just debug the code then you'll see where the exception occurrs.
I assume the subkey you're trying to open doesn't exist (it should start with "Software", not ".Software").
mav
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mav.northwind wrote:
I assume the subkey you're trying to open doesn't exist (it should start with "Software", not ".Software").
Thank you, thank you!!!
The 'dot' did it! Pfff, if I knew that it was that simple...
I presume that once you get a little more experienced, you don't make any more mistakes like that. (I hope...)
Thanks again...
Markali
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Though I am not much more experienced than you ,I may say, once you started to face with errors , you learn how to deal with them , esp. using debugger (watch is a great tool btw..), understand and comment on errors, than find the appropriate solution..
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I am writing an application that allows user login by windows authentication (includes domain and username).
For example:
Username: MYDOMAIN\MyUser
Domain:MYDOMAIN
If this username is valid, application will check for user's role, if user's role is BUILTIN\Users then this user can do their works.
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It's nice that you are writing an application, but what's your question?
mav
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And?
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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oops... I am trying to write this application, but I don't know how to write. Sorry,
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Right, thats nice, so what's your specific question?
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the code is from my work:
class Test
{
static void Main()
{
int a = 0x79de61c0; //2044617152;
a += 0x12345678;
//a 应为 0x8c12b838; //-1944930248
if( a< 0 ) a = -a;
//string str1 = a.ToString();
System.Console.WriteLine( a );
//string str2 = a.ToString();
}
}
Here: if( a<0 ) a=-a; means a will be positive(>0)
if we use line "str1" or "str2", we get a negative number:
-1944930248。
Why a.ToString() effects the result?
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I'm not getting a positive number at all, a.ToString() doesn't effect the result.
I think you should be using long instead of int , otherwise you'll be getting overflows all the time and unexpected results if you rely on the sign of your values.
You can use the checked keyword or the /checked compiler flag to detect such overflows.
mav
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dstang2000 wrote:
if( a< 0 ) a = -a;
And if you want the absolute value, try Math.Abs .
-- LuisR
Luis Alonso Ramos
Intelectix - Chihuahua, Mexico
Not much here: My CP Blog!
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When I debug, I found it is a terrible bug in JIT.
btw: JIT instruction is correct.
I've asked somebody to report the bug to MS.
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Hi Guys,
I missed a lecture yesterday and my lecturer was starting a new topic on logically linked arrays.Can you please explain this topic briefly to me with an example using a logically linked array.This will assist me the next time i go to class coz i wont be behind.
uni1985
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That's a flame bait if ever I saw one
Why don't you ask one of your mates who attended the lecture to explain it to you?
You weren't there and neither were we, so how come you think we can tell you what your professor taught?
Let's reverse the situation: You find out what your professor wants you to know about logically linked arrays and then write an article here so that everybody can learn a valuable lesson.
mav
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lindiwe wrote:
This will assist me the next time i go to class coz i wont be behind.
Yes, you will be!
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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I have a label that when it is clicked, a text appear. How do I make it toggle?
Click once appear, click again disappear?
thanX for any suggestions
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You can use a boolean.
boolean isShow;
if(isShow)
{
showText
isShow=false
}
else
{
don`t show text
isShow=true
}
<italic>Work hard and a bit of luck is the key to success. You don`t need to be genius, to be rich.
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I created a windows with 5 tabs. On the design mode the taps appeared correct, when I look in the tab page (collection) property, they look OK but when I compiled the application, they are out of order.
Any ideas?
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I ran into this problem b4, it seems to be a little bug in VS.NET You need to manually change the order that the Tab Pages are added to the TabControl in the InitializeComponent() method of your code.
Find where your TabControl is initialized and change the order in which the Tab Pages are added to the Controls collection. This will fix your problem.
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OK. I was able to set the Form1.isMDIContainer property to true on the main form to prevent an exception from being thrown when showing a child form. Than I created a MDIChild form triggered by a menu item as the article from Microsoft says at: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbcon/html/vbconMDIApplications.asp but I encountered a problem.
First, when the Form.isMDIContainer property of the main form is set to true, it causes the background property of the form to only show a system color rather than the color that I would like the main form to display. This is explicitly stated in the article link above from Microsoft. Therefore, I thought that I could put a panel on the main form to display the color that I selected for the main form, but now when the MDIChild form is displayed it is displayed BEHIND the panel that was added to the main form.
How do I get the MDIChild form to display IN FRONT OF the panel rather than behind the panel. I tried to set the code in a menu item like so but it did not work.
<br />
formChild frm = new frmChild();<br />
frm.MDIParent = this;<br />
frm.Show();<br />
The MDIChild form shows behind the panel. I had tried to change the code to frm.MDIParent = panelMain but it would not assign a panel to a form. I find it very hard to believe that I am forced to choose either between a gray background (system color) OR the possibility of MDI form functionality.
I would appreciate some additional input from an MDI expert who has done some sort of a work-around solution. The color that I want to use for the background color of the main form is simply not in the list of system colors. Need your assistance to either bring the MDIChild form in front of the panel or to change the color permitted for the parent form from a system color. Tried to set the MDIChild form TopMost property to true but that did not work either. Any suggestions?
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