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• does class/object models have a out-of-the-box equivalent to a database foreign key constraint

  - by Greg

  Hi, Does does class/object models have a out-of-the-box equivalent to a database foreign key constraint? Assume the language is C# please. That is say Class A has a field that references Class B and vica-versa. If I have Object A & B (instantiated from these classes) what happens if I delete Object B? Does it auto-delete or throw a constraint issue if it still exists in Object A as a reference? That is, for this scenario is there a way to ensure when a Object A is delete that either (a) object B is delete like a cascade delete, or (b) a constraint exception is thrown as the expectation is that the reference in Class B should be non-null?

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• How do I link up a button click event between a class and a module automatically?

  - by CowKingDeluxe

  I have this code (which doesn't work): Public Class Form1 End Class Public Module test1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Form1.Button1.Click MsgBox("HI") End Sub End Module I know I could handle the button click event in Form1, and then call a function in test1, but I would like to handle the button click event directly in the test1 module. Is there a way to automatically send UI events from the Form1 class to another module?

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• How to set title and class in the HTML for the options of a ModelChoiceField?

  - by celopes

  I have a model class MyModel(models.Model): name = models.CharField(max_length=80, unique=True) parent = models.ForeignKey('self', null=True, blank=True) I want to render a ModelChoiceField for that model that looks like: <select name="mymodel" id="id_mymodel"> <option value="1" title="Value 1" class="">Value 1</option> <option value="2" title="Value 2" class="Value 1">Value 2</option> </select> The differences between this output and the default output for a ModelChoiceField are the title and class elements in the OPTION tag. They don't exist in ModelChoiceField's default output. For my purposes: The title element is supposed to be the Option Name. The class element is supposed to be self.parent.name. (this is my problem) So, in the HTML snippet above, Value 1 has no parent and Value 2 has a parent of Value 1. What is the best mechanism to change ModelChoiceField's default HTML output? EDIT: I understand how to create a new Widget for rendering HTML. The problem is how to render a value from the underlying model in each of the options.

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• How to replace the following character with an empty space in c#?

  - by Pandiya Chendur

  One of my datatable column value looks like the below, How to replace that character which is square in shape with a \n or an empty space using c#? Any suggestion...

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• How to replace the following character with an empty space?

  - by Pandiya Chendur

  One of my datatable column value looks like the below, How to replace that character which is square in shape with a \n or an empty space using c#? Any suggestion... ClientAddress column holds value of a Multiline textbox....

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• How can I make my password fields always empty?

  - by ggfan

  I have a form field where users can change their passwords, but if they set their settings to remember passwords, their password shows up. Is there a way to make the field always empty? So that they always have to type their password. <label for="oldpassword" class="styled">Old password:</label> <input type="password" id="oldpassword" name="oldpassword"/><br />

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• if i want to build logger class in c++ or java what should it be singletone or static

  - by user63898

  Hello all general question is i like to build logger class that writes to single log file from different classes in my application what should the logger class be singletone or static class

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• How do I reference a pointer from a different class?

  - by Justagruvn

  First off, I despise singletons with a passion. Though I should probably be trying to use one, I just don't want to. I want to create a data class (that is instantiated only once by a view controller on loading), and then using a different class, message the crap out of that data instance until it is brimming with so much data, it smiles. So, how do I do that? I made a pointer to the instance of the data class when I instantiated it. I'm now over in a separate view controller, action occurs, and I want to update the initial data object. I think I need to reference that object by way of pointer, but I have no idea how to do that. Yes, I've set properties and getters and setters, which seem to work, but only in the initial view controller class. Peace Love applesauce.

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• How to define custom exception class in Java, the easiest way?

  - by yegor256

  I'm trying to define my own exception class the easiest way, and this is what I'm getting: public class MyException extends Exception {} public class Foo { public bar() throws MyException { throw new MyException("try again please"); } } This is what Java compiler says: cannot find symbol: constructor MyException(java.lang.String) I had a feeling that this constructor has to be inherited from java.lang.Exception, isn't it?

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• In what package should a "Settings" class be placed?

  - by Tom

  I'm in the middle of building an application but found myself too easily creating new packages without keeping the project's structure in mind. Now, I'm trying to redo the whole project structure on paper first. I am using a Settings class with public properties, accessed as settings for several other classes around the project. Now, since this Settings class applies for the whole project, I am unsure if it should be packaged and if so, in what kind of package should it exist? Or should it be in the root (the default package) with the main application class? I've been thinking about putting it in my utils package, then again I don't think it really is an utlity. Any strategies on how to decide on such package structure for example for a Settings class?

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• Is there anything else other than class, interface or Enum?

  - by GK

  As we know to generate a class file there should be atleast one class or interface or an Enum should be declared in the java file. So i was curious that is there anything else as well other the mentioned which can cause a class file generation. Or did anybody think that as we can declare the above mentioned, we can declare this(Which you think) as well ?

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• Strange rails behaviour: class methods doesnt work as expected...

  - by Totty

  In Profile model class def add_friendship_request(friend_id) Friendship.testing2 # doesnt work Profile.testing2 # work end def self.testing2 'ss' end in my Friendship model class def self.testing2 'ss' end I got this error: undefined method `testing2' for #<Class:0x58eea7c>

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• How to access a superclass method from a nested class?

  - by m01

  I hope this code explains the problem: class Foo { void a() { / *stuff */ } } class Bar extends Foo { void a() { throw new Exception("This is not allowed for Bar"); } class Baz { void blah() { // how to access Foo.a from here? } } } I know that I may be doing something wrong, because inheritance perhaps shouldn't be used in such way. But it's the easiest way in my situation. And, beside that, I'm just curious. Is it possible?

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• Why are there so many javascript files in my empty MVC 2 project?

  - by niaher

  When creating an empty MVC 2 project, I have a lot of javascript files in my Scripts folder. Why? Will removing them affect my application?

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• How can I check if a html document includes script tags that are not empty using a regular expressio

  - by flobr

  I am trying to check if a html document includes script tags that are not empty using regular expressions. The regular expression should match any script tag with a content other than whitespaces or linebreaks. I have tried <script\b[^>]*>[^.+$]</script> but this regex only finds script tags with one space.

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• Are there any "gotchas" to watch for in using a Class (object) within itself?

  - by Clay Nichols

  I've got a Registry class and there are a few Registry values that I want to access from within that Registry class. (There is a bit of a calculation with these values so I thought I'd just put all that code right in the Registry Class itself). So we might have something within our RegistryRoutine.cls like: Function GetMyValue() as integer Dim R as new RegistryRoutine <calculations> GetMyValue=R.GetRegisetryValue (HKEY, key, value, etc.) End Function

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• Why the function from immediate parent is called and not from grandparent class. Is this called func

  - by sandeep

  class A { public: void test () { cout<<"In A"; } }; class B :public A { public: void test () { cout<<"In B"; } }; class C : public B { public: int c; }; int main() { C c; c.test(); } The result is: In B...

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• How do I return '' for an empty node's text() in XPath?

  - by joeforker

  <td></td><td>foo</td> I would like to return ['', 'foo'] but libxml's xpath //td/text() returns just ['foo']. How do I find the empty tag as '' instead of (not matched)?

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• Pointers and collection of pointers in C++. How to properly delete.

  - by Julen

  Hello, This is a newbe question but I have alwasy doubts with pointers in C++. This is the situation. I have a class A which as a collection (a vector actually) of pointers of class B. This same class A has another collection of pointers to class C. Finally the objects of class B have also a collection to pointers to class C which point to the same instances the class A points to. My question is, if I delete a member of class-C-type pointer in class B, what happens to the pointer in class A that points to the deleted instance of class C? How this situation has to be treated? Thanks a lot in advance! Julen.

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• Objective C Class Method to control all existing instances?

  - by spadict

  Is it possible to use the class methods of some NSObject I've made to controls all existing instances? I want a delegate class to be able to send messages to the Object's class methods which can then react appropriately with everything out there.

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• Django: Is it possible to attach media files (css, javascript etc) to a View-class?

  - by mrmclovin

  I can't fins any information on how to define css or javascript files in a view like: class MyView(View): .... class Media: css = { 'all' : 'mystyle.css' } If you have a form you can do like: class MyForm(ModelForm): .... class Media: css = { 'all' : 'mystyle.css' } And then in the template you can print the files like; {{ form.media.css }} I like that Syntax very much and I like to keep the View-specific css files in the app-directory. Does anyone know if it's possible? Thanks!

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• Setting an attribute property to the type of the decorated class.

  - by cmaduro

  Is it possible to get the decorated class' type inside of the custom attribute's class? For example: [MetadataAttribute] [AttributeUsage(AttributeTargets.Class | AttributeTargets.Property, AllowMultiple = false)] public class ViewAttribute : ExportAttribute { public object TargetRegion { get; set; } public Type ViewModel { get; set; } public Type Module { get; set; } public ViewAttribute() : base(typeof(UserControl)) { Module = GetDecoratedClassType(); //I need this method } } In the following example GetDecoratedClassType() would return HomeView [View] HomeView MyHomeView { get; set; }

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• Restrict type of method parameter with two or more class names?

  - by Kirzilla

  Hello, We can restrict type of method parameters; for example, we should say that function parameter should be an instance of object described in class with name "Some Class". function some_function(Some_Class $object) { } Is there any php native posibilities to restrict method parameter with two or more classes? For examle, "Some Class" or "Some Class2" or "Some Class3". Or maybe there is any way to restrict method parameter with classes which implements interface with name "Some_Interface"? Thank you.

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• What happens if we load already loaded class again?

  - by GK

  I mean we have a class which is already loaded in JVM. and in some other method we are unknowingly trying to load that same class, So in this situation what happens? ie will there be any error or exception saying its already loaded. If not, then is it possible that we can have modified class with some extra features and load it whenever it is required that is Hot Deployment.

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• Why would $this->data show up an empty array after submit?

  - by user150253

  In Cakephp Why would $this-data show up an empty array after submit? i am using the security component.

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