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  • how to edit controls in a system::thread

    - by Ian Lundberg
    I need to be able to add items to a listbox inside of a thread. Code is below. 1. ref class Work 2. { 3. public: 4. static void RecieveThread() 5. { 6. while (true) 7. { 8. ZeroMemory(cID, 64); 9. ZeroMemory(message, 256); 10. if(recv(sConnect, message, 256, NULL) != SOCKET_ERROR && recv(sConnect, cID, 64, NULL) != SOCKET_ERROR) 11. { 12. ID = atoi(cID); 13. String^ meep = gcnew String(message); 14. lbxMessages->Items->Add(meep); 15. check = 1; 16. } 17. } 18. } 19. }; I get the error Error: a nonstatic member reference must be relative to a specific object on line 14. Is there any way to get it to let me do that? Because if I try to use String^ meep; outside of that Thread it doesn't contain anything. It works PERFECT when I use it within the thread but not outside of it. I need to be able to add that message to the listbox. If anyone can help I would appreciate it.

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  • Call instance method with objc_msgSend

    - by user772349
    I'm trying to use the objc_msgSend method to call some method dynamically. Say I want call some method in Class B from Class A and there are two methods in class B like: - (void) instanceTestWithStr1:(NSString *)str1 str2:(NSString *)str1; + (void) methodTestWithStr1:(NSString *)str1 str2:(NSString *)str1; And I can call the class method like this in Class A successfully: objc_msgSend(objc_getClass("ClassB"), sel_registerName("methodTestWithStr1:str2:"), @"111", @"222"); And I can call the instance method like this in Class A successfully as well: objc_msgSend([[objc_getClass("ClassB") alloc] init], sel_registerName("instanceTestWithStr1:str2:"), @"111", @"222"); But the thing is to get a instance of Class B I have to call "initWithXXXXX:XXXXXX:XXXXXX" instead of "init" so that to pass some necessary parameters to class B to do the init stuff. So I stored a instance of ClassB in class A as variable: self.classBInstance = [[ClassB alloc] initWithXXXXX:XXXXXX:XXXXXX]; And then I call the method like this (successfully): The problem is, I want to call a method by simply applying the classname and the method sel like "ClassName" and "SEL" and then call it dynamically: If it's a class method. then call it like: objc_msgSend(objc_getClass("ClassName"), sel_registerName("SEL")); If it's a instance method, find the existing class instance variable in the calling class then: objc_msgSend([self.classInstance, sel_registerName("SEL")); So I want to know if there is any way to: Check if a class has a given method (I found "responseToSelector" will be the one) Check if a given method in class method or instance method (maybe can use responseToSelector as well) Check if a class has a instance variable of a given class So I can call a instance method like: objc_msgSend(objc_getClassInstance(self, "ClassB"), sel_registerName("SEL"));

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  • Visual Basic: Newbie questions.

    - by Omega
    Hello there. I am starting to learn visual basic. So far, it is quite simple and easy to use. I am liking it! Anyway, I want to make applications a little bit more complex. So far I have done very silly things. I would appreciate if you could help me with these: How do I open a new window (form)? Maybe I click a button on my main form and another form pops up. How do I "deactivate" the main form while the new form is running? (if I try to click the main form, an error sound plays) So my second form has a text field and a "OK" button. If I click it, the second form closes activating the main form again. I want to "pass" the text in the text field from the second form to the first one. How do I do that? Thank you, I am enjoying this new programming environment (didn't use Visual Studio much before)

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  • Handling primary key duplicates in a data warehouse load

    - by Meff
    I'm currently building an ETL system to load a data warehouse from a transactional system. The grain of my fact table is the transaction level. In order to ensure I don't load duplicate rows I've put a primary key on the fact table, which is the transaction ID. I've encountered a problem with transactions being reversed - In the transactional database this is done via a status, which I pick up and I can work out if the transaction is being done, or rolled back so I can load a reversal row in the warehouse. However, the reversal row will have the same transaction ID and so I get a primary key violation. I've solved this for now by negating the primary key, so transaction ID 1 would be a payment, and transaction ID -1 (In the warehouse only) would be the reversal. I have considered an alternative of generating a BIT column, where 0 is normal and 1 is reversal, then making the PK the transaction ID and the BIT column. My question is, is this a good practice, and has anyone else encountered anything like this? For reference, this is a payment processing system, so values will not be modified, so there will only ever be transactions and reversals.

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  • javascript unable to locate a form using the ID tag

    - by ihake
    Here's my problem: I'm trying to set up a simple mobile contact form with a captcha built in. The page I'm working on can be found here: http://m.lancasterpainting.com/contact.php I'm using the following php contact form: http://www.html-form-guide.com/contact-form/php-email-contact-form.html I want to first say that I'm not the only one to run into this problem. After googling the issue, I've found multiple people struggling with this, but no-one seems to have an answer. Now for the problem... As you can see if you visit the page, each time the page is accessed, an error appears that says "Error: couldnot get Form object contact_form". I cannot--for the life of me--figure out why the javascript can't find the form I pass it. I call the function that generates this error at the top of the page: var frmvalidator = new Validator("contact_form"); The form I'm referencing is as follows in the HTML code: <div data-role="page" data-theme="e" id="contact_form" name="contact_form" data-position="inline"> ... And the function that is called that generates the error can be found in an external .js file here: http://m.lancasterpainting.com/scripts/gen_validatorv31.js Is there something that I am simply not seeing? Why can't the javascript locate the form? Thanks so much to anyone that helps with this.

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  • Error Expected Loop VBScript

    - by Yoko21
    I have a script that opens up an excel file if the password provided is correct. If its wrong, it prompts a message. It works perfectly when I add a loop at the end. However, the problem is whenever the password is wrong the script won't stop asking for the password because of the loop. What I want is the script to quit/close if the password is wrong. I tried to remove the loop and replaced it with "wscript.quit" but it always prompts the message "expected loop". Here is the code I made. password = "pass" do ask=inputbox ("Please enter password:","DProject") select case ask case password answer=true Set xl = CreateObject("Excel.application") xl.Application.Workbooks.Open "C:\Users\test1\Desktop\test.xlsx" xl.Application.Visible = True Set xl = Nothing wscript.quit end select answer=false x=msgbox("Password incorrect... Aborting") loop until answer=true Is it possible to put a message like that counts when aborting. like "Aborting in 3.... 2... 1".

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  • fluent nhibernate - storing and retrieving three classes in/from one table

    - by Will I Am
    Noob question. I have this situation where I have these objects: class Address { string Street; string City; ... } class User { string UserID; Address BillingAddress; Address MailingAddress; ... } What is the proper way of storing this data using (fluent) nHibernate? I could use a separate Address table and create a reference, but they are 1:1 relationships so I don't really want to incur the overhead of a join. Ideally I would store this as a single flat record. So, my question is, what is the proper way of storing an instance of class 'User' in such a way that it stores its contents and also the two addresses as a single record? My knowledge is failing me on how I can store this information in such a way that the two Address records get different column names (e.g. BillingAddress_Street and MailingAddress_Street, for example), and also how to read a record back into a User instance.

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  • Export to csv, string w/ comma in it, splits it up

    - by Brad
    This code exports data into a csv file, which is opened within Excel. When a string has a comma within it, it messes up the order of the data. I need help modifying my code below to resolve any data that contains a comma within it, to not to create a new column. I am assuming it will pass each string within double quotes, so any comma within those quotes, then it will make an exception. Any help is appreciated. $result = mysql_query("select lname, fname, email, dtelephone, etelephone, contactwhen, comments, thursday, friday, saturday, sunday, monday FROM volunteers_2010"); $csv_output .= "Last Name,First Name,Email,Telephone (Day),Telephone (Evening),Contact When,Comments,Thursday,Friday,Saturday,Sunday,Monday,Comments\n"; $i = 0; if (mysql_num_rows($result) > 0) { while ($row = mysql_fetch_assoc($result)) { $csv_output .= $row['Field'].", "; $i++; } } $csv_output .= "\n"; $values = mysql_query("SELECT lname, fname, email, dtelephone, etelephone, contactwhen, comments, thursday, friday, saturday, sunday, monday FROM volunteers_2010 WHERE venue_id = $venue_id"); while ($rowr = mysql_fetch_row($values)) { for ($j=0;$j<$i;$j++) { $csv_output .= $rowr[$j].", "; } $csv_output .= "\n"; }

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  • What's the best way to link formal specs to JIRA enchancement requests?

    - by Adam
    What's the best way to link formal specs to JIRA enhancement requests? I want to track changes to specifications using JIRA. Ideally, I'd like to refer to a functional ID reference in a JIRA ticket (e.g. MYAPPAPPROVAL LOGICMAIN SCREEN), so that program managers can retrospectively categorise defects. The reason for this, is so that QA scripts and documentation tickets can be searched/categorised meaningfully in the tracking system. There seems to be a million possible ways to do this, e.g. should I write a custom component to select functional IDs from a tree? should I write the specs in confluence, or another CMS with a TrackBack facility? should I include a link to the documentation URL? should I use some other 3rd party plugin application? should I use some Atlassian application that i'm unaware of? am I using the wrong tracking tool/process to measure spec growth? What's the best way, in your experience?

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  • Doctrine YAML not generating correctly? Or is this markup wrong?

    - by ropstah
    I'm trying to get a many-to-many relationship between Users and Settings. The models seem to be generated correctly, however the following query fails: "User_Setting" with an alias of "us" in your query does not reference the parent component it is related to. $q = new Doctrine_RawSql(); $q->select('{s.*}, {us.*}') ->from('User u CROSS JOIN Setting s LEFT JOIN User_Setting us ON us.usr_auto_key = u.usr_auto_key AND us.set_auto_key = s.set_auto_key') ->addComponent('s', 'Setting s INDEXBY s.set_auto_key') ->addComponent('us', 'User_Setting us') ->where(u.usr_auto_key = ?',$this->usr_auto_key); $this->settings = $q->execute(); Does anyone spot a problem? This is my YAML: User: connection: default tableName: User columns: usr_auto_key: type: integer(4) fixed: false unsigned: false primary: true autoincrement: true notnull: true email: type: string(100) fixed: false unsigned: false primary: false default: '' notnull: true autoincrement: false password: type: string(32) fixed: false unsigned: false primary: false default: '' notnull: true autoincrement: false relations: Setting: class: Setting foreignAlias: User refClass: User_Setting local: usr_auto_key foreign: set_auto_key Setting: connection: default tableName: Setting columns: set_auto_key: type: integer(4) fixed: false unsigned: false primary: true autoincrement: true notnull: true name: type: string(50) fixed: false unsigned: false primary: false notnull: true autoincrement: false User_Setting: connection: default tableName: User_Setting columns: usr_auto_key: type: integer(4) fixed: false unsigned: false primary: true autoincrement: false notnull: true set_auto_key: type: integer(4) fixed: false unsigned: false primary: true autoincrement: false notnull: true value: type: string(255) fixed: false unsigned: false primary: false notnull: true autoincrement: false relations: Setting: foreignAlias: User_Setting local: set_auto_key foreign: set_auto_key User: foreignAlias: User_Setting local: usr_auto_key foreign: usr_auto_key

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  • How to implement instance numbering?

    - by Joan Venge
    I don't know if the title is clear but basically I am trying to implement something like this: public class Effect { public int InternalId ... public void ResetName() ... } When ResetName is called, this will reset the name of the object to: "Effect " + someIndex; So if I have 5 instances of Effect, they will be renamed to: "Effect 1" "Effect 2" "Effect 3" ... So I have another method (ResetNames) in another manager/container type that calls ResetName for each instance. And right now I have to pass an integer to ResetName while keeping a counter myself inside ResetNames. But this feels not as clean and this prevents me from calling ResetName myself outside the manager class, which is valid. How to do this better/cleaner? As for the InternalId, it's just some id that stores the creation order for everything. So I can't just rely on these, because the numbers are large, like 32000, etc. EDIT: Container ResetNames code: int count = 1; var effects = this.Effects.OrderBy ( n => n.InternalId ); foreach ( Effect effect in effects ) { effect.ResetName ( count ); ++count; }

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  • How to make 2 incompatible types, but with the same members, interchangeable?

    - by Quigrim
    Yesterday 2 of the guys on our team came to me with an uncommon problem. We are using a third-party component in one of our winforms applications. All the code has already been written against it. They then wanted to incorporate another third-party component, by the same vender, into our application. To their delight they found that the second component had the exact same public members as the first. But to their dismay, the 2 components have completely separate inheritance hierarchies, and implement no common interfaces. Makes you wonder... Well, makes me wonder. An example of the problem: public class ThirdPartyClass1 { public string Name { get { return "ThirdPartyClass1"; } } public void DoThirdPartyStuff () { Console.WriteLine ("ThirdPartyClass1 is doing its thing."); } } public class ThirdPartyClass2 { public string Name { get { return "ThirdPartyClass2"; } } public void DoThirdPartyStuff () { Console.WriteLine ("ThirdPartyClass2 is doing its thing."); } } Gladly they felt copying and pasting the code they wrote for the first component was not the correct answer. So they were thinking of assigning the component instant into an object reference and then modifying the code to do conditional casts after checking what type it was. But that is arguably even uglier than the copy and paste approach. So they then asked me if I can write some reflection code to access the properties and call the methods off the two different object types since we know what they are, and they are exactly the same. But my first thought was that there goes the elegance. I figure there has to be a better, graceful solution to this problem.

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  • Is it possible to aggregate over differing where clauses?

    - by BenAlabaster
    Is it possible to calculate multiple aggregates based on differing where clauses? For instance: Let's say I have two tables, one for Invoice and one for InvoiceLineItems. The invoice table has a total field for the invoice total, and each of the invoice line item records in the InvoiceLineItems table contains a field that denotes whether the line item is discountable or not. I want three sum totals, one where Discountable = 0 and one where Discountable = 1 and one where Discountable is irrelevant. Such that my output would be: InvoiceNumber Total DiscountableTotal NonDiscountableTotal ------------- ----- ----------------- -------------------- 1 53.27 27.27 16.00 2 38.94 4.76 34.18 3... The only way I've found so far is by using something like: Select i.InvoiceNumber, i.Total, t0.Total As DiscountableTotal, t1.Total As NonDiscountableTotal From Invoices i Left Join ( Select InvoiceNumber, Sum(Amount), From InvoiceLineItems Where Discountable = 0 Group By InvoiceNumber ) As t0 On i.InvoiceNumber = t0.InvoiceNumber Left Join ( Select InvoiceNumber, Sum(Amount) From InvoiceLineItems Where Discountable = 1 Group By InvoiceNumber ) As t1 On i.InvoiceNumber = t1.InvoiceNumber This seems somewhat cumbersome, it would be nice if I could do something like: Select InvoiceNumber, Sum(Amount) Where Discountable = 1 As Discountable Sum(Amount) Where Discountable = 0 As NonDiscountable Group By InvoiceNumber I realize that SQL is completely invalid, but it logically portrays what I'm trying to do... TIA P.S. I need this to run on a SQL Server 2000 instance, but I am also interested (for future reference) if/how I would achieve this on SQL Server 2005/2008.

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  • cin.getline() equivalent when getting a char from a function.

    - by Aaron
    From what I understand cin.getLine gets the first char(which I think it a pointer) and then gets that the length. I have used it when cin for a char. I have a function that is returning a pointer to the first char in an array. Is there an equivalent to get the rest of the array into a char that I can use the entire array. I explained below what I am trying to do. The function works fine, but if it would help I could post the function. cmd_str[0]=infile();// get the pointer from a function cout<<"pp1>"; cout<< "test1"<<endl; // cin.getline(cmd_str,500);something like this with the array from the function cout<<cmd_str<<endl; this would print out the entire array cout<<"test2"<<endl; length=0; length= shell(cmd_str);// so I could pass it to this function

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  • how to organize classes in ruby if they are literal subclasses

    - by RetroNoodle
    I know that title didn't make sense, Im sorry! Its hard to word what I am trying to ask. I had trouble googling it for the same reason. So this isn't even Ruby specific, but I am working in ruby and I am new to it, so bear with me. So you have a class that is a document. Inside each document, you have sentences, and each sentence has words. Words will have properties, like "noun" or a count of how many times they are used in the document, etc. I would like each of the elements, document, sentence, word be an object. Now, if you think literally - sentences are in documents, and words are in sentences. Should this be organized literally like this as well? Like inside the document class you will define and instantiate the sentence objects, and inside the sentence class you will define and instantiate the words? Or, should everything be separate and reference each other? Like the word class would sit outside the sentence class but the sentence class would be able to instantiate and work with words? This is a basic OOP question I guess, and I suppose you could argue to do it either way. What do you guys think? Each sentence in the document could be stored in a hash of sentence objects inside the document object, and each word in the sentence could be stored in a hash of word objects inside the sentence. I dont want to code myself into a corner here, thats why I am asking, plus I have wondered this before in other situations. Thank you!

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  • What rules govern the copying of variables in Javascript closures?

    - by int3
    I'd just like to check my understanding of variable copying in Javascript. From what I gather, variables are passed/assigned by reference unless you explicitly tell them to create a copy with the new operator. But I'm a little uncertain when it comes to using closures. Say I have the following code: var myArray = [1, 5, 10, 15, 20]; var fnlist = []; for (var i in myArray) { var data = myArray[i]; fnlist.push(function() { var x = data; console.log(x); }); } fnlist[2](); // returns 20 I gather that this is because fnlist[2] only looks up the value of data at the point where it is invoked. So I tried an alternative tack: var myArray = [1, 5, 10, 15, 20]; var fnlist = []; for (var i in myArray) { var data = myArray[i]; fnlist.push(function() { var x = data; return function() { console.log(x); } }()); } fnlist[2](); // returns 10 So now it returns the 'correct' value. Am I right to say that it works because a function resolves all variable references to their 'constant' values when it is invoked? Or is there a better way to explain it? Any explanations / links to explanations regarding this referencing / copying business would be appreciated as well. Thanks!

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  • singledispatch in class, how to dispatch self type

    - by yanxinyou
    Using python3.4. Here I want use singledispatch to dispatch different type in __mul__ method . The code like this : class Vector(object): ## some code not paste @functools.singledispatch def __mul__(self, other): raise NotImplementedError("can't mul these type") @__mul__.register(int) @__mul__.register(object) # Becasue can't use Vector , I have to use object def _(self, other): result = Vector(len(self)) # start with vector of zeros for j in range(len(self)): result[j] = self[j]*other return result @__mul__.register(Vector) # how can I use the self't type @__mul__.register(object) # def _(self, other): pass # need impl As you can see the code , I want support Vector*Vertor , This has Name error Traceback (most recent call last): File "p_algorithms\vector.py", line 6, in <module> class Vector(object): File "p_algorithms\vector.py", line 84, in Vector @__mul__.register(Vector) # how can I use the self't type NameError: name 'Vector' is not defined The question may be How Can I use class Name a Type in the class's method ? I know c++ have font class statement . How python solve my problem ? And it is strange to see result = Vector(len(self)) where the Vector can be used in method body .

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  • How to start x-axis labels(dates) from 0th position without using set_range(..)

    - by Rishi2686
    Hi there, First of all, I am really a newbie for flash charts. I have problem in using it. I am developing an app which gets values from database for chart. I have a line on chart, there are dates on x-axis starting from 0th position. I have dates 03-06-2010 and 05-06-2010 right now and may increase in future. When I set range of 1 month i.e 1st jun to 30th jun , it does not show lines but show values on y-axis. When I use range, i am not able to pass array of above two dates from database to chart, and viceversa. Here is my code-snippet can you give some hint. $x = new x_axis(); $x->set_range( mktime(0, 0, 0, 6, 1, date('Y')), // <-- min == 1st Jan, this year mktime(0, 0, 0, 6, 16, date('Y')) // <-- max == 31st Jan, this year ); $x->set_steps(86400); $labels = new x_axis_labels(); $labels->text('#date: jS, M Y#'); $labels->set_steps(86400); $labels->visible_steps(1); $labels->rotate(90); //$labels->set_labels($data_4); // date_4 is array of database values $x->set_labels($labels);

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  • Database PK-FK design for future-effective-date entries?

    - by Scott Balmos
    Ultimately I'm going to convert this into a Hibernate/JPA design. But I wanted to start out from purely a database perspective. We have various tables containing data that is future-effective-dated. Take an employee table with the following pseudo-definition: employee id INT AUTO_INCREMENT ... data fields ... effectiveFrom DATE effectiveTo DATE employee_reviews id INT AUTO_INCREMENT employee_id INT FK employee.id Very simplistic. But let's say Employee A has id = 1, effectiveFrom = 1/1/2011, effectiveTo = 1/1/2099. That employee is going to be changing jobs in the future, which would in theory create a new row, id = 2 with effectiveFrom = 7/1/2011, effectiveTo = 1/1/2099, and id = 1's effectiveTo updated to 6/30/2011. But now, my program would have to go through any table that has a FK relationship to employee every night, and update those FK to reference the newly-effective employee entry. I have seen various postings in both pure SQL and Hibernate forums that I should have a separate employee_versions table, which is where I would have all effective-dated data stored, resulting in the updated pseudo-definition below: employee id INT AUTO_INCREMENT employee_versions id INT AUTO_INCREMENT employee_id INT FK employee.id ... data fields ... effectiveFrom DATE effectiveTo DATE employee_reviews id INT AUTO_INCREMENT employee_id INT FK employee.id Then to get any actual data, one would have to actually select from employee_versions with the proper employee_id and date range. This feels rather unnatural to have this secondary "versions" table for each versioned entity. Anyone have any opinions, suggestions from your own prior work, etc? Like I said, I'm taking this purely from a general SQL design standpoint first before layering in Hibernate on top. Thanks!

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  • Show dialog while loading new screen

    - by darkdusky
    I have a front screen with a button which opens a second screen. The second screen can take a few seconds to load so I want to display a dialog while loading. My problem is the dialog does not display while loading second screen, but it displays when I return to first page from the second page. If I comment out the "startActivity" to open second page the dialog shows fine. I'm fairly new to android programming - I guess it has something to do with threads. //code snippet from inside onCreate: NewGame.setOnClickListener(new View.OnClickListener() { public void onClick(View arg0) { //does not get displayed before 2nd page opens showDialog(DIALOG2_KEY); //shows fine if next 2 lines commented out Intent i = new Intent(screen1.this, SudukuXL.class); startActivity(i); I've dealt with the dialog showing on returning to the front screen using onPause(). I've tried using threads to seperate the dialog from the startActivity but I've had no luck. Any help would be appreciated. I used code from Android examples to create dialog. I include below for reference: protected Dialog onCreateDialog(int id) { switch (id) { case DIALOG2_KEY: { ProgressDialog dialog = new ProgressDialog(this); dialog.setMessage("Loading..."); dialog.setIndeterminate(true); dialog.setCancelable(true); return dialog; } } return null; }

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  • .NET memory leak?

    - by SA
    I have an MDI which has a child form. The child form has a DataGridView in it. I load huge amount of data in the datagrid view. When I close the child form the disposing method is called in which I dispose the datagridview this.dataGrid.Dispose(); this.dataGrid = null; When I close the form the memory doesn't go down. I use the .NET memory profiler to track the memory usage. I see that the memory usage goes high when I initially load the data grid (as expected) and then becomes constant when the loading is complete. When I close the form it still remains constant. However when I take a snapshot of the memory using the memory profiler, it goes down to what it was before loading the file. Taking memory snapshot causes it to forcefully run garbage collector. What is going on? Is there a memory leak? Or do I need to run the garbage collector forcefully? More information: When I am closing the form I no longer need the information. That is why I am not holding a reference to the data.

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  • Automate Field Entry in outside site

    - by JClaspill
    I am attempting to automate the entry of data into form fields. The problem is that this data (user/pass) is not known by the user. I'm not expressly hiding it from them, but they also don't need to know it. This is used to automate logins on several of our outside partner websites, who do not want our agents knowing their passwords. Sadly, most of these sites do not have any APIs I can work with... so I have to get the user logged in. I tried using an iframe and javascript, but I ran into the issue of security permissions denying it access. And sadly, our clients do not have access to add our domain to their sites(they seem to be 3rd party). Requirements: - Display webpage - Automatically enter data into fields Would be nice: - Automate signin similar to form.submit() - Flash/AJAX support. These seem to give the VB app issues. Is there a way to do this via javascript/html, and if not, do you have any recommendations for C#/php/asp.net options? PS: I am not sure what this techinque is called, so google isn't helping me it seems. Please set me straight on the terminology of what I am actually trying to accomplish.

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  • How to know the type of an object in a list?

    - by nacho4d
    Hi, I want to know the type of object (or type) I have in my list so I wrote this: void **list; //list of references list = new void * [2]; Foo foo = Foo(); const char *not_table [] = {"tf", "ft", 0 }; list[0] = &foo; list[1] = not_table; if (dynamic_cast<LogicProcessor*>(list[0])) { //ERROR here ;( printf("Foo was found\n"); } if (dynamic_cast<char*> (list[0])) { //ERROR here ;( printf("char was found\n"); } but I get : error: cannot dynamic_cast '* list' (of type 'void*') to type 'class Foo*' (source is not a pointer to class) error: cannot dynamic_cast '* list' (of type 'void*') to type 'char*' (target is not pointer or reference to class) Why is this? what I am doing wrong here? Is dynamic_cast what I should use here? Thanks in advance EDIT: I know above code is much like plain C and surely sucks from the C++ point of view but is just I have the following situation and I was trying something before really implementing it: I have two arrays of length n but both arrays will never have an object at the same index. Hence, or I have array1[i]!=NULL or array2[i]!=NULL. This is obviously a waste of memory so I thought everything would be solved if I could have both kind of objects in a single array of length n. I am looking something like Cocoa's (Objective-C) NSArray where you don't care about the type of the object to be put in. Not knowing the type of the object is not a problem since you can use other method to get the class of a certain later. Is there something like it in c++ (preferably not third party C++ libraries) ? Thanks in advance ;)

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  • Passing a string to a function in C++

    - by Chef Flambe
    I want to pass a string like "Celcius" into a function that I have but I keep getting errors tossed back at me from the Function. System::Console::WriteLine' : none of the 19 overloads could convert all the argument types I figure I just have something simple wrong. Can someone point out my mistake please? Using MS Visual C++ 2010 I've posted the offending code. The other functions (not posted) work fine. void PrintResult( double result, std::string sType ); // Print result and string // to the console //============================================================================================= // start of main //============================================================================================= void main( void ) { ConsoleKeyInfo CFM; // Program Title and Description ProgramDescription(); // Menu Selection and calls to data retrieval/calculation/result Print CFM=ChooseFromMenu(); switch(CFM.KeyChar) // ************************************************************ { //* case '1' : PrintResult(F2C(GetTemperature()),"Celsius"); //* break; //* //* case '2' : PrintResult(C2F(GetTemperature()),"Fahrenheit"); //* break; //* //* default : Console::Write("\n\nSwitch : Case !!!FAILURE!!!"); //* } //************************************************************ system("pause"); return; } //Function void PrintResult( double result, std::string sType ) { Console::WriteLine("\n\nThe converted temperature is {0:F2} degrees {1}\n\n",result,sType); return; }

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  • Is False == 0 and True == 1 in Python an implementation detail or guaranteed by the language?

    - by EOL
    Is it guaranteed that False == 0 and True == 1, in Python? For instance, is it in any way guaranteed that the following code will always produce the same results, whatever the version of Python (existing and in the foreseeable future)? 0 == False # True 1 == True # True ['zero', 'one'][False] # is 'zero' Any reference to the official documentation would be much appreciated! Other comments would be appreciated too… :) Edit: As noted in many answers, bool inherits from int. The question can therefore be recast as: "Is this an implementation detail that might change in the future, or does the documentation officially say that programmers can rely on booleans inheriting from integers?". This question is relevant for writing robust code that won't fail because of implementation details! Edit 2: The original question is still open, I believe (even though I accepted what I thought was the closest answer): even though Python 3 officially recognizes booleans as integers, I have not yet seen any official integer values for False and True… It therefore looks to me like it is best to stay clear from the assumption that False==0 and True==1.

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