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  • Casting as Interface? Awesome.

    - by cam
    I was just experimenting around with one of my programs, trying to make it looks prettier and I found something interesting. I have an interface that 4 classes inherit from. I found that if I pass the Class as an object to a method like so: ClassTest classtest = new ClassTest(); DoOperation(classtest); private void DoOperation(object o) { ((InterfaceClass)o).DoThis(); } So I can pass any type of class that inherits from InterfaceClass, and it will preform the proper interface operation? This is the coolest thing I've ever found from OOP (something I've never really studied) I really thought interfaces were created for the sole purpose of organization for developers. Are there more uses for interfaces than this?

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  • is it good to wite multiple time <script type="text/javascript"> on one php page?

    - by I Like PHP
    i m using many tiny java script code at one php page, i always write java script code in below style <script type="text/javascript"> // <![CDATA[ ----code 1--------- // ]]> </script> <script type="text/javascript"> // <![CDATA[ ----code 2----- // ]]> </script> <script type="text/javascript"> // <![CDATA[ $(document).ready.(function(){ }); // ]]> </script> i want to know that is it good practice to write separate <script type="text/javascript"></script> on same page or we have to write all java script code under one time declaration

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  • What is the difference between type.__getattribute__ and object.__getattribute__?

    - by Neil G
    Given: In [37]: class A: ....: f = 1 ....: In [38]: class B(A): ....: pass ....: In [39]: getattr(B, 'f') Out[39]: 1 Okay, that either calls super or crawls the mro? In [40]: getattr(A, 'f') Out[40]: 1 This is expected. In [41]: object.__getattribute__(A, 'f') Out[41]: 1 In [42]: object.__getattribute__(B, 'f') --------------------------------------------------------------------------- AttributeError Traceback (most recent call last) <ipython-input-42-de76df798d1d> in <module>() ----> 1 object.__getattribute__(B, 'f') AttributeError: 'type' object has no attribute 'f' What is getattribute not doing that getattr does? In [43]: type.__getattribute__(B, 'f') Out[43]: 1 What?! type.__getattribute__ calls super but object's version doesn't? In [44]: type.__getattribute__(A, 'f') Out[44]: 1

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  • How to style just one type of input field without also affecting other input types with CSS

    - by James
    Is there a way to write style rules that will only influence text fields. Suppose I have the following: <div id="helloDiv"> <input type="text" name="something" /><br /> <input type="checkbox" name="somethingElse" /><br /> <input type="submit" name="go" /> </div> div#helloDiv input { border: 1px solid red; } The problem with the above CSS rule is that it will affect ALL input fields not just input text but also radio buttons, submit buttons, etc. So is there a cross browser solution to affect just one type of input field within a div or other page element (without resorting to assigning the input fields styles individually).

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  • help me with typecasting problem ...

    - by Anil Namde
    I would like to create a function which can take two arguments object and type and then type cast the object to appropriate type using the type parameter. Is that possible ? how can i achieve it ? public class TEST { public int test; } object ot = new TEST(); Type type = typeof(TEST); TEST t = (type)ot; //Function will be something like this public string SearializeObject(Object obj, Type t) { //check if obj is of type t if(obj is of type t){ //cast obj to type t to read it ((Type t)obj).someMethod } }

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  • How to manually set button input type in ASP.NET?

    - by jawonlee
    I have a jQueryUI dialog with some textboxes, plus a button. Right now, the asp:Button tag used to generate the button automatically sets its type as type="submit". The structure of the dialog is such that pressing enter at any of the textboxes should not call the button click event. It seems like the cleanest way to solve the problem, if it is doable, is to manually set the button's type to something other than submit. Is there a way to do this?

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  • How do you increase Internet Explorer 7's "Select as you type" timeout for comboboxes?

    - by Iain Fraser
    In Internet Explorer 7, you can select options from comboboxes by typing the first few letters of the value you're looking for. However, some people in our organisation are a bit slow and can't type their selection quick enough, with the result that the timeout is triggered and the "select as you type" process starts all over again. Example: If I type A-R-M-A (looking for Armadale) then wait half a second and type D, I'll get selections beginning with the letter D. What I want to do is increase this timeout to allow for slow typers. (We're in a corporate environment so rolling out these changes to all machines won't be a problem).

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  • Java: How to get Unicode name of a character (or its type category)?

    - by java.is.for.desktop
    Hello, everyone! The Character class in Java defines methods which check a given char argument for equality with certain Unicode chars or for belonging to some type category. These chars and type categories are named. As stated in given javadoc, examples for named chars are HORIZONTAL TABULATION, FORM FEED, ...; example for named type categories are SPACE_SEPARATOR, PARAGRAPH_SEPARATOR, ... However, being byte or int values instead of enums, the name of these types are "hidden" at runtime. So, is there a possibility to get characters' and/or type categories' names at runtime?

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  • iPhone SDK: How to determine keyboard type within a UIKeyboardDidShowNotification?

    - by iPhone Developer
    Hello, I need to know the current keyboard type. I was setting an instance variable in - (BOOL)textFieldShouldBeginEditing:(UITextField *)textField However, testing has shown that this is not always reliable because of the asynchronous nature of notifications. What I am wondering is if anyone can tell me how to determine the current keyboard type within a notification? - (void)keyboardDidShow:(NSNotification *) { // Need way to determine keyboard type here } Thanks.

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  • How does the dataset determine the return type of a scalar query?

    - by Tobias Funke
    I am attempting to add a scalar query to a dataset. The query is pretty straight forward, it's just adding up some decimal values in a few columns and returning them. I am 100% confident that only one row and one column is returned, and that it is of decimal type (SQL money type). The problem is that for some reason, the generated method (in the .designer.cs code file) is returning a value of type object, when it should be decimal. What's strange is that there's another scalar query that has the exact same SQL but is returning decimal like it should. How does the dataset designer determine the data type, and how can I tell it to return decimal?

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  • Ways to make (relatively) safe assumptions about the type of concrete subclasses?

    - by Kylotan
    I have an interface (defined as a abstract base class) that looks like this: class AbstractInterface { public: bool IsRelatedTo(const AbstractInterface& other) const = 0; } And I have an implementation of this (constructors etc omitted): class ConcreteThing { public: bool IsRelatedTo(const AbstractInterface& other) const { return m_ImplObject.has_relationship_to(other.m_ImplObject); } private: ImplementationObject m_ImplObject; } The AbstractInterface forms an interface in Project A, and the ConcreteThing lives in Project B as an implementation of that interface. This is so that code in Project A can access data from Project B without having a direct dependency on it - Project B just has to implement the correct interface. Obviously the line in the body of the IsRelatedTo function cannot compile - that instance of ConcreteThing has an m_ImplObject member, but it can't assume that all AbstractInterfaces do, including the other argument. In my system, I can actually assume that all implementations of AbstractInterface are instances of ConcreteThing (or subclasses thereof), but I'd prefer not to be casting the object to the concrete type in order to get at the private member, or encoding that assumption in a way that will crash without a diagnostic later if this assumption ceases to hold true. I cannot modify ImplementationObject, but I can modify AbstractInterface and ConcreteThing. I also cannot use the standard RTTI mechanism for checking a type prior to casting, or use dynamic_cast for a similar purpose. I have a feeling that I might be able to overload IsRelatedTo with a ConcreteThing argument, but I'm not sure how to call it via the base IsRelatedTo(AbstractInterface) method. It wouldn't get called automatically as it's not a strict reimplementation of that method. Is there a pattern for doing what I want here, allowing me to implement the IsRelatedTo function via ImplementationObject::has_relationship_to(ImplementationObject), without risky casts? (Also, I couldn't think of a good question title - please change it if you have a better one.)

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  • How does the dataset designer determine the return type of a scalar query?

    - by Tobias Funke
    I am attempting to add a scalar query to a dataset. The query is pretty straight forward, it's just adding up some decimal values in a few columns and returning them. I am 100% confident that only one row and one column is returned, and that it is of decimal type (SQL money type). The problem is that for some reason, the generated method (in the .designer.cs code file) is returning a value of type object, when it should be decimal. What's strange is that there's another scalar query that has the exact same SQL but is returning decimal like it should. How does the dataset designer determine the data type, and how can I tell it to return decimal?

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  • Can we turn on the iphone's number keyboard WITHOUT using type=number?

    - by Simple As Could Be
    I'm making a webapp, and I'd like an input field to show the Iphone's number keypad. I understand that type=number will make the keypad show the way I'd like. The trouble is that type=number does not support placeholder text. So if I would like this: Expiration Date: [eg: 2010] I can not get it to work, and also show the right keyboard. Is there a way to force the iphone keyboard into number mode without using the number input type?

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  • jquery datepicker only works on <input type=text> within Chrome?

    - by birdFEEDER
    I have a very simple page that's usings jquery's datepicker. I have: <input id=datepicker type=image src='cal.png'> When I click on the image in FF/IE, it works as expected, but does not work in Chrome (ver. 4.1.249.1064). However if I simply change to "type=text", it works within Chrome. So my question is this: am I allowed to use Datepicker with "type=image"?

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  • is it good to write multiple time(separate) <script type="text/javascript"> on one php page?

    - by I Like PHP
    i m using many tiny java script code at one php page, i always write java script code in below style <script type="text/javascript"> // <![CDATA[ ----code 1--------- // ]]> </script> <script type="text/javascript"> // <![CDATA[ ----code 2----- // ]]> </script> <script type="text/javascript"> // <![CDATA[ $(document).ready.(function(){ }); // ]]> </script> i want to know that is it good practice to write separate <script type="text/javascript"></script> on same page or we have to write all java script code under one time declaration

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  • C#/.NET Little Wonders: The Predicate, Comparison, and Converter Generic Delegates

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. In the last three weeks, we examined the Action family of delegates (and delegates in general), the Func family of delegates, and the EventHandler family of delegates and how they can be used to support generic, reusable algorithms and classes. This week I will be completing my series on the generic delegates in the .NET Framework with a discussion of three more, somewhat less used, generic delegates: Predicate<T>, Comparison<T>, and Converter<TInput, TOutput>. These are older generic delegates that were introduced in .NET 2.0, mostly for use in the Array and List<T> classes.  Though older, it’s good to have an understanding of them and their intended purpose.  In addition, you can feel free to use them yourself, though obviously you can also use the equivalents from the Func family of delegates instead. Predicate<T> – delegate for determining matches The Predicate<T> delegate was a very early delegate developed in the .NET 2.0 Framework to determine if an item was a match for some condition in a List<T> or T[].  The methods that tend to use the Predicate<T> include: Find(), FindAll(), FindLast() Uses the Predicate<T> delegate to finds items, in a list/array of type T, that matches the given predicate. FindIndex(), FindLastIndex() Uses the Predicate<T> delegate to find the index of an item, of in a list/array of type T, that matches the given predicate. The signature of the Predicate<T> delegate (ignoring variance for the moment) is: 1: public delegate bool Predicate<T>(T obj); So, this is a delegate type that supports any method taking an item of type T and returning bool.  In addition, there is a semantic understanding that this predicate is supposed to be examining the item supplied to see if it matches a given criteria. 1: // finds first even number (2) 2: var firstEven = Array.Find(numbers, n => (n % 2) == 0); 3:  4: // finds all odd numbers (1, 3, 5, 7, 9) 5: var allEvens = Array.FindAll(numbers, n => (n % 2) == 1); 6:  7: // find index of first multiple of 5 (4) 8: var firstFiveMultiplePos = Array.FindIndex(numbers, n => (n % 5) == 0); This delegate has typically been succeeded in LINQ by the more general Func family, so that Predicate<T> and Func<T, bool> are logically identical.  Strictly speaking, though, they are different types, so a delegate reference of type Predicate<T> cannot be directly assigned to a delegate reference of type Func<T, bool>, though the same method can be assigned to both. 1: // SUCCESS: the same lambda can be assigned to either 2: Predicate<DateTime> isSameDayPred = dt => dt.Date == DateTime.Today; 3: Func<DateTime, bool> isSameDayFunc = dt => dt.Date == DateTime.Today; 4:  5: // ERROR: once they are assigned to a delegate type, they are strongly 6: // typed and cannot be directly assigned to other delegate types. 7: isSameDayPred = isSameDayFunc; When you assign a method to a delegate, all that is required is that the signature matches.  This is why the same method can be assigned to either delegate type since their signatures are the same.  However, once the method has been assigned to a delegate type, it is now a strongly-typed reference to that delegate type, and it cannot be assigned to a different delegate type (beyond the bounds of variance depending on Framework version, of course). Comparison<T> – delegate for determining order Just as the Predicate<T> generic delegate was birthed to give Array and List<T> the ability to perform type-safe matching, the Comparison<T> was birthed to give them the ability to perform type-safe ordering. The Comparison<T> is used in Array and List<T> for: Sort() A form of the Sort() method that takes a comparison delegate; this is an alternate way to custom sort a list/array from having to define custom IComparer<T> classes. The signature for the Comparison<T> delegate looks like (without variance): 1: public delegate int Comparison<T>(T lhs, T rhs); The goal of this delegate is to compare the left-hand-side to the right-hand-side and return a negative number if the lhs < rhs, zero if they are equal, and a positive number if the lhs > rhs.  Generally speaking, null is considered to be the smallest value of any reference type, so null should always be less than non-null, and two null values should be considered equal. In most sort/ordering methods, you must specify an IComparer<T> if you want to do custom sorting/ordering.  The Array and List<T> types, however, also allow for an alternative Comparison<T> delegate to be used instead, essentially, this lets you perform the custom sort without having to have the custom IComparer<T> class defined. It should be noted, however, that the LINQ OrderBy(), and ThenBy() family of methods do not support the Comparison<T> delegate (though one could easily add their own extension methods to create one, or create an IComparer() factory class that generates one from a Comparison<T>). So, given this delegate, we could use it to perform easy sorts on an Array or List<T> based on custom fields.  Say for example we have a data class called Employee with some basic employee information: 1: public sealed class Employee 2: { 3: public string Name { get; set; } 4: public int Id { get; set; } 5: public double Salary { get; set; } 6: } And say we had a List<Employee> that contained data, such as: 1: var employees = new List<Employee> 2: { 3: new Employee { Name = "John Smith", Id = 2, Salary = 37000.0 }, 4: new Employee { Name = "Jane Doe", Id = 1, Salary = 57000.0 }, 5: new Employee { Name = "John Doe", Id = 5, Salary = 60000.0 }, 6: new Employee { Name = "Jane Smith", Id = 3, Salary = 59000.0 } 7: }; Now, using the Comparison<T> delegate form of Sort() on the List<Employee>, we can sort our list many ways: 1: // sort based on employee ID 2: employees.Sort((lhs, rhs) => Comparer<int>.Default.Compare(lhs.Id, rhs.Id)); 3:  4: // sort based on employee name 5: employees.Sort((lhs, rhs) => string.Compare(lhs.Name, rhs.Name)); 6:  7: // sort based on salary, descending (note switched lhs/rhs order for descending) 8: employees.Sort((lhs, rhs) => Comparer<double>.Default.Compare(rhs.Salary, lhs.Salary)); So again, you could use this older delegate, which has a lot of logical meaning to it’s name, or use a generic delegate such as Func<T, T, int> to implement the same sort of behavior.  All this said, one of the reasons, in my opinion, that Comparison<T> isn’t used too often is that it tends to need complex lambdas, and the LINQ ability to order based on projections is much easier to use, though the Array and List<T> sorts tend to be more efficient if you want to perform in-place ordering. Converter<TInput, TOutput> – delegate to convert elements The Converter<TInput, TOutput> delegate is used by the Array and List<T> delegate to specify how to convert elements from an array/list of one type (TInput) to another type (TOutput).  It is used in an array/list for: ConvertAll() Converts all elements from a List<TInput> / TInput[] to a new List<TOutput> / TOutput[]. The delegate signature for Converter<TInput, TOutput> is very straightforward (ignoring variance): 1: public delegate TOutput Converter<TInput, TOutput>(TInput input); So, this delegate’s job is to taken an input item (of type TInput) and convert it to a return result (of type TOutput).  Again, this is logically equivalent to a newer Func delegate with a signature of Func<TInput, TOutput>.  In fact, the latter is how the LINQ conversion methods are defined. So, we could use the ConvertAll() syntax to convert a List<T> or T[] to different types, such as: 1: // get a list of just employee IDs 2: var empIds = employees.ConvertAll(emp => emp.Id); 3:  4: // get a list of all emp salaries, as int instead of double: 5: var empSalaries = employees.ConvertAll(emp => (int)emp.Salary); Note that the expressions above are logically equivalent to using LINQ’s Select() method, which gives you a lot more power: 1: // get a list of just employee IDs 2: var empIds = employees.Select(emp => emp.Id).ToList(); 3:  4: // get a list of all emp salaries, as int instead of double: 5: var empSalaries = employees.Select(emp => (int)emp.Salary).ToList(); The only difference with using LINQ is that many of the methods (including Select()) are deferred execution, which means that often times they will not perform the conversion for an item until it is requested.  This has both pros and cons in that you gain the benefit of not performing work until it is actually needed, but on the flip side if you want the results now, there is overhead in the behind-the-scenes work that support deferred execution (it’s supported by the yield return / yield break keywords in C# which define iterators that maintain current state information). In general, the new LINQ syntax is preferred, but the older Array and List<T> ConvertAll() methods are still around, as is the Converter<TInput, TOutput> delegate. Sidebar: Variance support update in .NET 4.0 Just like our descriptions of Func and Action, these three early generic delegates also support more variance in assignment as of .NET 4.0.  Their new signatures are: 1: // comparison is contravariant on type being compared 2: public delegate int Comparison<in T>(T lhs, T rhs); 3:  4: // converter is contravariant on input and covariant on output 5: public delegate TOutput Contravariant<in TInput, out TOutput>(TInput input); 6:  7: // predicate is contravariant on input 8: public delegate bool Predicate<in T>(T obj); Thus these delegates can now be assigned to delegates allowing for contravariance (going to a more derived type) or covariance (going to a less derived type) based on whether the parameters are input or output, respectively. Summary Today, we wrapped up our generic delegates discussion by looking at three lesser-used delegates: Predicate<T>, Comparison<T>, and Converter<TInput, TOutput>.  All three of these tend to be replaced by their more generic Func equivalents in LINQ, but that doesn’t mean you shouldn’t understand what they do or can’t use them for your own code, as they do contain semantic meanings in their names that sometimes get lost in the more generic Func name.   Tweet Technorati Tags: C#,CSharp,.NET,Little Wonders,delegates,generics,Predicate,Converter,Comparison

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  • How to resolve "dpkg: error processing /var/cache/apt/archives/python-apport_2.0.1-0ubuntu9_all.deb"?

    - by raz7588
    Update Manager will not update although I have over 100 updates to do I get a error message like this: installArchives() failed: Extracting templates from packages: 29%% Extracting templates from packages: 58%% Extracting templates from packages: 88%% Extracting templates from packages: 100%% Preconfiguring packages ... Extracting templates from packages: 29%% Extracting templates from packages: 58%% Extracting templates from packages: 88%% Extracting templates from packages: 100%% Preconfiguring packages ... Extracting templates from packages: 29%% Extracting templates from packages: 58%% Extracting templates from packages: 88%% Extracting templates from packages: 100%% Preconfiguring packages ... Extracting templates from packages: 29%% Extracting templates from packages: 58%% Extracting templates from packages: 88%% Extracting templates from packages: 100%% Preconfiguring packages ... (Reading database ... (Reading database ... 5%% (Reading database ... 10%% (Reading database ... 15%% (Reading database ... 20%% (Reading database ... 25%% (Reading database ... 30%% (Reading database ... 35%% (Reading database ... 40%% (Reading database ... 45%% (Reading database ... 50%% (Reading database ... 55%% (Reading database ... 60%% (Reading database ... 65%% (Reading database ... 70%% (Reading database ... 75%% (Reading database ... 80%% (Reading database ... 85%% (Reading database ... 90%% (Reading database ... 95%% (Reading database ... 100%% (Reading database ... 189751 files and directories currently installed.) Preparing to replace python-problem-report 2.0.1-0ubuntu7 (using .../python-problem-report_2.0.1-0ubuntu9_all.deb) ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error processing /var/cache/apt/archives/python-problem-report_2.0.1-0ubuntu9_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 No apport report written because MaxReports is reached already Traceback (most recent call last): File "/usr/bin/pycompile", line 39, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace python-apport 2.0.1-0ubuntu7 (using .../python-apport_2.0.1-0ubuntu9_all.deb) ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error processing /var/cache/apt/archives/python-apport_2.0.1-0ubuntu9_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 No apport report written because MaxReports is reached already Traceback (most recent call last): File "/usr/bin/pycompile", line 39, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace apport 2.0.1-0ubuntu7 (using .../apport_2.0.1-0ubuntu9_all.deb) ... apport stop/waiting Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error processing /var/cache/apt/archives/apport_2.0.1-0ubuntu9_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 No apport report written because MaxReports is reached already apport start/running Traceback (most recent call last): File "/usr/bin/pycompile", line 39, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace gnome-orca 3.4.1-0ubuntu0.1 (using .../gnome-orca_3.4.2-0ubuntu0.1_all.deb) ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error processing /var/cache/apt/archives/gnome-orca_3.4.2-0ubuntu0.1_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 No apport report written because MaxReports is reached already Traceback (most recent call last): File "/usr/bin/pycompile", line 39, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace python-piston-mini-client 0.7.2-0ubuntu1 (using .../python-piston-mini-client_0.7.2+bzr57-0ubuntu1_all.deb) ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error processing /var/cache/apt/archives/python-piston-mini-client_0.7.2+bzr57-0ubuntu1_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 No apport report written because MaxReports is reached already Traceback (most recent call last): File "/usr/bin/pycompile", line 39, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace oneconf 0.2.8 (using .../oneconf_0.2.8.1_all.deb) ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error processing /var/cache/apt/archives/oneconf_0.2.8.1_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 No apport report written because MaxReports is reached already Traceback (most recent call last): File "/usr/bin/pycompile", line 39, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace software-center 5.2.2 (using .../software-center_5.2.2.2_all.deb) ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Traceback (most recent call last): File "/usr/bin/pyclean", line 33, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error processing /var/cache/apt/archives/software-center_5.2.2.2_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 No apport report written because MaxReports is reached already Traceback (most recent call last): File "/usr/bin/pycompile", line 39, in <module> from debpython.namespace import add_namespace_files ValueError: bad marshal data (unknown type code) dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Preparing to replace libglade2-0 1:2.6.4-1ubuntu1 (using .../libglade2-0_1%%3a2.6.4-1ubuntu1.1_amd64.deb) ... Unpacking replacement libglade2-0 ... Preparing to replace libv4l-0 0.8.6-1ubuntu1 (using .../libv4l-0_0.8.6-1ubuntu2_amd64.deb) ... De-configuring libv4l-0:i386 ... Unpacking replacement libv4l-0 ... Preparing to replace libv4l-0:i386 0.8.6-1ubuntu1 (using .../libv4l-0_0.8.6-1ubuntu2_i386.deb) ... Unpacking replacement libv4l-0:i386 ... Preparing to replace libv4lconvert0:i386 0.8.6-1ubuntu1 (using .../libv4lconvert0_0.8.6-1ubuntu2_i386.deb) ... De-configuring libv4lconvert0 ... Unpacking replacement libv4lconvert0:i386 ... Preparing to replace libv4lconvert0 0.8.6-1ubuntu1 (using .../libv4lconvert0_0.8.6-1ubuntu2_amd64.deb) ... Unpacking replacement libv4lconvert0 ... Errors were encountered while processing: /var/cache/apt/archives/python-problem-report_2.0.1-0ubuntu9_all.deb /var/cache/apt/archives/python-apport_2.0.1-0ubuntu9_all.deb /var/cache/apt/archives/apport_2.0.1-0ubuntu9_all.deb /var/cache/apt/archives/gnome-orca_3.4.2-0ubuntu0.1_all.deb /var/cache/apt/archives/python-piston-mini-client_0.7.2+bzr57-0ubuntu1_all.deb /var/cache/apt/archives/oneconf_0.2.8.1_all.deb /var/cache/apt/archives/software-center_5.2.2.2_all.deb Error in function: SystemError: E:Sub-process /usr/bin/dpkg returned an error code (1) Setting up libglade2-0 (1:2.6.4-1ubuntu1.1) ... dpkg: error processing gnome-orca (--configure): Package is in a very bad inconsistent state - you should reinstall it before attempting configuration. dpkg: error processing python-problem-report (--configure): Package is in a very bad inconsistent state - you should reinstall it before attempting configuration. Setting up libv4lconvert0 (0.8.6-1ubuntu2) ... Setting up libv4lconvert0:i386 (0.8.6-1ubuntu2) ... dpkg: error processing python-piston-mini-client (--configure): Package is in a very bad inconsistent state - you should reinstall it before attempting configuration. Setting up libv4l-0 (0.8.6-1ubuntu2) ... Setting up libv4l-0:i386 (0.8.6-1ubuntu2) ... dpkg: dependency problems prevent configuration of python-apport: python-apport depends on python-problem-report (>= 0.94); however: Package python-problem-report is not configured yet. dpkg: error processing python-apport (--configure): dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of software-center: software-center depends on python-piston-mini-client (>= 0.1+bzr29); however: Package python-piston-mini-client is not configured yet. dpkg: error processing software-center (--configure): dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of oneconf: oneconf depends on python-piston-mini-client (>= 0.3+bzr32-0ubuntu1); however: Package python-piston-mini-client is not configured yet. dpkg: error processing oneconf (--configure): dependency problems - leaving unconfigured dpkg: dependency problems prevent configuration of apport: apport depends on python-apport (>= 2.0.1-0ubuntu7); however: Package python-apport is not configured yet. dpkg: error processing apport (--configure): dependency problems - leaving unconfigured Processing triggers for libc-bin ... ldconfig deferred processing now taking place This has been going on for two weeks now and I cannot get any updates. Any help would be great.

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  • Creating a dynamic, extensible C# Expando Object

    - by Rick Strahl
    I love dynamic functionality in a strongly typed language because it offers us the best of both worlds. In C# (or any of the main .NET languages) we now have the dynamic type that provides a host of dynamic features for the static C# language. One place where I've found dynamic to be incredibly useful is in building extensible types or types that expose traditionally non-object data (like dictionaries) in easier to use and more readable syntax. I wrote about a couple of these for accessing old school ADO.NET DataRows and DataReaders more easily for example. These classes are dynamic wrappers that provide easier syntax and auto-type conversions which greatly simplifies code clutter and increases clarity in existing code. ExpandoObject in .NET 4.0 Another great use case for dynamic objects is the ability to create extensible objects - objects that start out with a set of static members and then can add additional properties and even methods dynamically. The .NET 4.0 framework actually includes an ExpandoObject class which provides a very dynamic object that allows you to add properties and methods on the fly and then access them again. For example with ExpandoObject you can do stuff like this:dynamic expand = new ExpandoObject(); expand.Name = "Rick"; expand.HelloWorld = (Func<string, string>) ((string name) => { return "Hello " + name; }); Console.WriteLine(expand.Name); Console.WriteLine(expand.HelloWorld("Dufus")); Internally ExpandoObject uses a Dictionary like structure and interface to store properties and methods and then allows you to add and access properties and methods easily. As cool as ExpandoObject is it has a few shortcomings too: It's a sealed type so you can't use it as a base class It only works off 'properties' in the internal Dictionary - you can't expose existing type data It doesn't serialize to XML or with DataContractSerializer/DataContractJsonSerializer Expando - A truly extensible Object ExpandoObject is nice if you just need a dynamic container for a dictionary like structure. However, if you want to build an extensible object that starts out with a set of strongly typed properties and then allows you to extend it, ExpandoObject does not work because it's a sealed class that can't be inherited. I started thinking about this very scenario for one of my applications I'm building for a customer. In this system we are connecting to various different user stores. Each user store has the same basic requirements for username, password, name etc. But then each store also has a number of extended properties that is available to each application. In the real world scenario the data is loaded from the database in a data reader and the known properties are assigned from the known fields in the database. All unknown fields are then 'added' to the expando object dynamically. In the past I've done this very thing with a separate property - Properties - just like I do for this class. But the property and dictionary syntax is not ideal and tedious to work with. I started thinking about how to represent these extra property structures. One way certainly would be to add a Dictionary, or an ExpandoObject to hold all those extra properties. But wouldn't it be nice if the application could actually extend an existing object that looks something like this as you can with the Expando object:public class User : Westwind.Utilities.Dynamic.Expando { public string Email { get; set; } public string Password { get; set; } public string Name { get; set; } public bool Active { get; set; } public DateTime? ExpiresOn { get; set; } } and then simply start extending the properties of this object dynamically? Using the Expando object I describe later you can now do the following:[TestMethod] public void UserExampleTest() { var user = new User(); // Set strongly typed properties user.Email = "[email protected]"; user.Password = "nonya123"; user.Name = "Rickochet"; user.Active = true; // Now add dynamic properties dynamic duser = user; duser.Entered = DateTime.Now; duser.Accesses = 1; // you can also add dynamic props via indexer user["NickName"] = "AntiSocialX"; duser["WebSite"] = "http://www.west-wind.com/weblog"; // Access strong type through dynamic ref Assert.AreEqual(user.Name,duser.Name); // Access strong type through indexer Assert.AreEqual(user.Password,user["Password"]); // access dyanmically added value through indexer Assert.AreEqual(duser.Entered,user["Entered"]); // access index added value through dynamic Assert.AreEqual(user["NickName"],duser.NickName); // loop through all properties dynamic AND strong type properties (true) foreach (var prop in user.GetProperties(true)) { object val = prop.Value; if (val == null) val = "null"; Console.WriteLine(prop.Key + ": " + val.ToString()); } } As you can see this code somewhat blurs the line between a static and dynamic type. You start with a strongly typed object that has a fixed set of properties. You can then cast the object to dynamic (as I discussed in my last post) and add additional properties to the object. You can also use an indexer to add dynamic properties to the object. To access the strongly typed properties you can use either the strongly typed instance, the indexer or the dynamic cast of the object. Personally I think it's kinda cool to have an easy way to access strongly typed properties by string which can make some data scenarios much easier. To access the 'dynamically added' properties you can use either the indexer on the strongly typed object, or property syntax on the dynamic cast. Using the dynamic type allows all three modes to work on both strongly typed and dynamic properties. Finally you can iterate over all properties, both dynamic and strongly typed if you chose. Lots of flexibility. Note also that by default the Expando object works against the (this) instance meaning it extends the current object. You can also pass in a separate instance to the constructor in which case that object will be used to iterate over to find properties rather than this. Using this approach provides some really interesting functionality when use the dynamic type. To use this we have to add an explicit constructor to the Expando subclass:public class User : Westwind.Utilities.Dynamic.Expando { public string Email { get; set; } public string Password { get; set; } public string Name { get; set; } public bool Active { get; set; } public DateTime? ExpiresOn { get; set; } public User() : base() { } // only required if you want to mix in seperate instance public User(object instance) : base(instance) { } } to allow the instance to be passed. When you do you can now do:[TestMethod] public void ExpandoMixinTest() { // have Expando work on Addresses var user = new User( new Address() ); // cast to dynamicAccessToPropertyTest dynamic duser = user; // Set strongly typed properties duser.Email = "[email protected]"; user.Password = "nonya123"; // Set properties on address object duser.Address = "32 Kaiea"; //duser.Phone = "808-123-2131"; // set dynamic properties duser.NonExistantProperty = "This works too"; // shows default value Address.Phone value Console.WriteLine(duser.Phone); } Using the dynamic cast in this case allows you to access *three* different 'objects': The strong type properties, the dynamically added properties in the dictionary and the properties of the instance passed in! Effectively this gives you a way to simulate multiple inheritance (which is scary - so be very careful with this, but you can do it). How Expando works Behind the scenes Expando is a DynamicObject subclass as I discussed in my last post. By implementing a few of DynamicObject's methods you can basically create a type that can trap 'property missing' and 'method missing' operations. When you access a non-existant property a known method is fired that our code can intercept and provide a value for. Internally Expando uses a custom dictionary implementation to hold the dynamic properties you might add to your expandable object. Let's look at code first. The code for the Expando type is straight forward and given what it provides relatively short. Here it is.using System; using System.Collections.Generic; using System.Linq; using System.Dynamic; using System.Reflection; namespace Westwind.Utilities.Dynamic { /// <summary> /// Class that provides extensible properties and methods. This /// dynamic object stores 'extra' properties in a dictionary or /// checks the actual properties of the instance. /// /// This means you can subclass this expando and retrieve either /// native properties or properties from values in the dictionary. /// /// This type allows you three ways to access its properties: /// /// Directly: any explicitly declared properties are accessible /// Dynamic: dynamic cast allows access to dictionary and native properties/methods /// Dictionary: Any of the extended properties are accessible via IDictionary interface /// </summary> [Serializable] public class Expando : DynamicObject, IDynamicMetaObjectProvider { /// <summary> /// Instance of object passed in /// </summary> object Instance; /// <summary> /// Cached type of the instance /// </summary> Type InstanceType; PropertyInfo[] InstancePropertyInfo { get { if (_InstancePropertyInfo == null && Instance != null) _InstancePropertyInfo = Instance.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly); return _InstancePropertyInfo; } } PropertyInfo[] _InstancePropertyInfo; /// <summary> /// String Dictionary that contains the extra dynamic values /// stored on this object/instance /// </summary> /// <remarks>Using PropertyBag to support XML Serialization of the dictionary</remarks> public PropertyBag Properties = new PropertyBag(); //public Dictionary<string,object> Properties = new Dictionary<string, object>(); /// <summary> /// This constructor just works off the internal dictionary and any /// public properties of this object. /// /// Note you can subclass Expando. /// </summary> public Expando() { Initialize(this); } /// <summary> /// Allows passing in an existing instance variable to 'extend'. /// </summary> /// <remarks> /// You can pass in null here if you don't want to /// check native properties and only check the Dictionary! /// </remarks> /// <param name="instance"></param> public Expando(object instance) { Initialize(instance); } protected virtual void Initialize(object instance) { Instance = instance; if (instance != null) InstanceType = instance.GetType(); } /// <summary> /// Try to retrieve a member by name first from instance properties /// followed by the collection entries. /// </summary> /// <param name="binder"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; // first check the Properties collection for member if (Properties.Keys.Contains(binder.Name)) { result = Properties[binder.Name]; return true; } // Next check for Public properties via Reflection if (Instance != null) { try { return GetProperty(Instance, binder.Name, out result); } catch { } } // failed to retrieve a property result = null; return false; } /// <summary> /// Property setter implementation tries to retrieve value from instance /// first then into this object /// </summary> /// <param name="binder"></param> /// <param name="value"></param> /// <returns></returns> public override bool TrySetMember(SetMemberBinder binder, object value) { // first check to see if there's a native property to set if (Instance != null) { try { bool result = SetProperty(Instance, binder.Name, value); if (result) return true; } catch { } } // no match - set or add to dictionary Properties[binder.Name] = value; return true; } /// <summary> /// Dynamic invocation method. Currently allows only for Reflection based /// operation (no ability to add methods dynamically). /// </summary> /// <param name="binder"></param> /// <param name="args"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { if (Instance != null) { try { // check instance passed in for methods to invoke if (InvokeMethod(Instance, binder.Name, args, out result)) return true; } catch { } } result = null; return false; } /// <summary> /// Reflection Helper method to retrieve a property /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="result"></param> /// <returns></returns> protected bool GetProperty(object instance, string name, out object result) { if (instance == null) instance = this; var miArray = InstanceType.GetMember(name, BindingFlags.Public | BindingFlags.GetProperty | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0]; if (mi.MemberType == MemberTypes.Property) { result = ((PropertyInfo)mi).GetValue(instance,null); return true; } } result = null; return false; } /// <summary> /// Reflection helper method to set a property value /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="value"></param> /// <returns></returns> protected bool SetProperty(object instance, string name, object value) { if (instance == null) instance = this; var miArray = InstanceType.GetMember(name, BindingFlags.Public | BindingFlags.SetProperty | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0]; if (mi.MemberType == MemberTypes.Property) { ((PropertyInfo)mi).SetValue(Instance, value, null); return true; } } return false; } /// <summary> /// Reflection helper method to invoke a method /// </summary> /// <param name="instance"></param> /// <param name="name"></param> /// <param name="args"></param> /// <param name="result"></param> /// <returns></returns> protected bool InvokeMethod(object instance, string name, object[] args, out object result) { if (instance == null) instance = this; // Look at the instanceType var miArray = InstanceType.GetMember(name, BindingFlags.InvokeMethod | BindingFlags.Public | BindingFlags.Instance); if (miArray != null && miArray.Length > 0) { var mi = miArray[0] as MethodInfo; result = mi.Invoke(Instance, args); return true; } result = null; return false; } /// <summary> /// Convenience method that provides a string Indexer /// to the Properties collection AND the strongly typed /// properties of the object by name. /// /// // dynamic /// exp["Address"] = "112 nowhere lane"; /// // strong /// var name = exp["StronglyTypedProperty"] as string; /// </summary> /// <remarks> /// The getter checks the Properties dictionary first /// then looks in PropertyInfo for properties. /// The setter checks the instance properties before /// checking the Properties dictionary. /// </remarks> /// <param name="key"></param> /// /// <returns></returns> public object this[string key] { get { try { // try to get from properties collection first return Properties[key]; } catch (KeyNotFoundException ex) { // try reflection on instanceType object result = null; if (GetProperty(Instance, key, out result)) return result; // nope doesn't exist throw; } } set { if (Properties.ContainsKey(key)) { Properties[key] = value; return; } // check instance for existance of type first var miArray = InstanceType.GetMember(key, BindingFlags.Public | BindingFlags.GetProperty); if (miArray != null && miArray.Length > 0) SetProperty(Instance, key, value); else Properties[key] = value; } } /// <summary> /// Returns and the properties of /// </summary> /// <param name="includeProperties"></param> /// <returns></returns> public IEnumerable<KeyValuePair<string,object>> GetProperties(bool includeInstanceProperties = false) { if (includeInstanceProperties && Instance != null) { foreach (var prop in this.InstancePropertyInfo) yield return new KeyValuePair<string, object>(prop.Name, prop.GetValue(Instance, null)); } foreach (var key in this.Properties.Keys) yield return new KeyValuePair<string, object>(key, this.Properties[key]); } /// <summary> /// Checks whether a property exists in the Property collection /// or as a property on the instance /// </summary> /// <param name="item"></param> /// <returns></returns> public bool Contains(KeyValuePair<string, object> item, bool includeInstanceProperties = false) { bool res = Properties.ContainsKey(item.Key); if (res) return true; if (includeInstanceProperties && Instance != null) { foreach (var prop in this.InstancePropertyInfo) { if (prop.Name == item.Key) return true; } } return false; } } } Although the Expando class supports an indexer, it doesn't actually implement IDictionary or even IEnumerable. It only provides the indexer and Contains() and GetProperties() methods, that work against the Properties dictionary AND the internal instance. The reason for not implementing IDictionary is that a) it doesn't add much value since you can access the Properties dictionary directly and that b) I wanted to keep the interface to class very lean so that it can serve as an entity type if desired. Implementing these IDictionary (or even IEnumerable) causes LINQ extension methods to pop up on the type which obscures the property interface and would only confuse the purpose of the type. IDictionary and IEnumerable are also problematic for XML and JSON Serialization - the XML Serializer doesn't serialize IDictionary<string,object>, nor does the DataContractSerializer. The JavaScriptSerializer does serialize, but it treats the entire object like a dictionary and doesn't serialize the strongly typed properties of the type, only the dictionary values which is also not desirable. Hence the decision to stick with only implementing the indexer to support the user["CustomProperty"] functionality and leaving iteration functions to the publicly exposed Properties dictionary. Note that the Dictionary used here is a custom PropertyBag class I created to allow for serialization to work. One important aspect for my apps is that whatever custom properties get added they have to be accessible to AJAX clients since the particular app I'm working on is a SIngle Page Web app where most of the Web access is through JSON AJAX calls. PropertyBag can serialize to XML and one way serialize to JSON using the JavaScript serializer (not the DCS serializers though). The key components that make Expando work in this code are the Properties Dictionary and the TryGetMember() and TrySetMember() methods. The Properties collection is public so if you choose you can explicitly access the collection to get better performance or to manipulate the members in internal code (like loading up dynamic values form a database). Notice that TryGetMember() and TrySetMember() both work against the dictionary AND the internal instance to retrieve and set properties. This means that user["Name"] works against native properties of the object as does user["Name"] = "RogaDugDog". What's your Use Case? This is still an early prototype but I've plugged it into one of my customer's applications and so far it's working very well. The key features for me were the ability to easily extend the type with values coming from a database and exposing those values in a nice and easy to use manner. I'm also finding that using this type of object for ViewModels works very well to add custom properties to view models. I suspect there will be lots of uses for this - I've been using the extra dictionary approach to extensibility for years - using a dynamic type to make the syntax cleaner is just a bonus here. What can you think of to use this for? Resources Source Code and Tests (GitHub) Also integrated in Westwind.Utilities of the West Wind Web Toolkit West Wind Utilities NuGet© Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp  .NET  Dynamic Types   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Using the HTML5 &lt;input type=&quot;file&quot; multiple=&quot;multiple&quot;&gt; Tag in ASP.NET

    - by Rick Strahl
    Per HTML5 spec the <input type="file" /> tag allows for multiple files to be picked from a single File upload button. This is actually a very subtle change that's very useful as it makes it much easier to send multiple files to the server without using complex uploader controls. Please understand though, that even though you can send multiple files using the <input type="file" /> tag, the process of how those files are sent hasn't really changed - there's still no progress information or other hooks that allow you to automatically make for a nicer upload experience without additional libraries or code. For that you will still need some sort of library (I'll post an example in my next blog post using plUpload). All the new features allow for is to make it easier to select multiple images from disk in one operation. Where you might have required many file upload controls before to upload several files, one File control can potentially do the job. How it works To create a file input box that allows with multiple file support you can simply do:<form method="post" enctype="multipart/form-data"> <label>Upload Images:</label> <input type="file" multiple="multiple" name="File1" id="File1" accept="image/*" /> <hr /> <input type="submit" id="btnUpload" value="Upload Images" /> </form> Now when the file open dialog pops up - depending on the browser and whether the browser supports it - you can pick multiple files. Here I'm using Firefox using the thumbnail preview I can easily pick images to upload on a form: Note that I can select multiple images in the dialog all of which get stored in the file textbox. The UI for this can be different in some browsers. For example Chrome displays 3 files selected as text next to the Browse… button when I choose three rather than showing any files in the textbox. Most other browsers display the standard file input box and display the multiple filenames as a comma delimited list in the textbox. Note that you can also specify the accept attribute in the <input> tag, which specifies a mime-type to specify what type of content to allow.Here I'm only allowing images (image/*) and the browser complies by just showing me image files to display. Likewise I could use text/* for all text formats registered on the machine or text/xml to only show XML files (which would include xml,xst,xsd etc.). Capturing Files on the Server with ASP.NET When you upload files to an ASP.NET server there are a couple of things to be aware of. When multiple files are uploaded from a single file control, they are assigned the same name. In other words if I select 3 files to upload on the File1 control shown above I get three file form variables named File1. This means I can't easily retrieve files by their name:HttpPostedFileBase file = Request.Files["File1"]; because there will be multiple files for a given name. The above only selects the first file. Instead you can only reliably retrieve files by their index. Below is an example I use in app to capture a number of images uploaded and store them into a database using a business object and EF 4.2.for (int i = 0; i < Request.Files.Count; i++) { HttpPostedFileBase file = Request.Files[i]; if (file.ContentLength == 0) continue; if (file.ContentLength > App.Configuration.MaxImageUploadSize) { ErrorDisplay.ShowError("File " + file.FileName + " is too large. Max upload size is: " + App.Configuration.MaxImageUploadSize); return View("UploadClassic",model); } var image = new ClassifiedsBusiness.Image(); var ms = new MemoryStream(16498); file.InputStream.CopyTo(ms); image.Entered = DateTime.Now; image.EntryId = model.Entry.Id; image.ContentType = "image/jpeg"; image.ImageData = ms.ToArray(); ms.Seek(0, SeekOrigin.Begin); // resize image if necessary and turn into jpeg Bitmap bmp = Imaging.ResizeImage(ms.ToArray(), App.Configuration.MaxImageWidth, App.Configuration.MaxImageHeight); ms.Close(); ms = new MemoryStream(); bmp.Save(ms,ImageFormat.Jpeg); image.ImageData = ms.ToArray(); bmp.Dispose(); ms.Close(); model.Entry.Images.Add(image); } This works great and also allows you to capture input from multiple input controls if you are dealing with browsers that don't support multiple file selections in the file upload control. The important thing here is that I iterate over the files by index, rather than using a foreach loop over the Request.Files collection. The files collection returns key name strings, rather than the actual files (who thought that was good idea at Microsoft?), and so that isn't going to work since you end up getting multiple keys with the same name. Instead a plain for loop has to be used to loop over all files. Another Option in ASP.NET MVC If you're using ASP.NET MVC you can use the code above as well, but you have yet another option to capture multiple uploaded files by using a parameter for your post action method.public ActionResult Save(HttpPostedFileBase[] file1) { foreach (var file in file1) { if (file.ContentLength < 0) continue; // do something with the file }} Note that in order for this to work you have to specify each posted file variable individually in the parameter list. This works great if you have a single file upload to deal with. You can also pass this in addition to your main model to separate out a ViewModel and a set of uploaded files:public ActionResult Edit(EntryViewModel model,HttpPostedFileBase[] uploadedFile) You can also make the uploaded files part of the ViewModel itself - just make sure you use the appropriate naming for the variable name in the HTML document (since there's Html.FileFor() extension). Browser Support You knew this was coming, right? The feature is really nice, but unfortunately not supported universally yet. Once again Internet Explorer is the problem: No shipping version of Internet Explorer supports multiple file uploads. IE10 supposedly will, but even IE9 does not. All other major browsers - Chrome, Firefox, Safari and Opera - support multi-file uploads in their latest versions. So how can you handle this? If you need to provide multiple file uploads you can simply add multiple file selection boxes and let people either select multiple files with a single upload file box or use multiples. Alternately you can do some browser detection and if IE is used simply show the extra file upload boxes. It's not ideal, but either one of these approaches makes life easier for folks that use a decent browser and leaves you with a functional interface for those that don't. Here's a UI I recently built as an alternate uploader with multiple file upload buttons: I say this is my 'alternate' uploader - for my primary uploader I continue to use an add-in solution. Specifically I use plUpload and I'll discuss how that's implemented in my next post. Although I think that plUpload (and many of the other packaged JavaScript upload solutions) are a better choice especially for large uploads, for simple one file uploads input boxes work well enough. The advantage of this solution is that it's very easy to handle on the server side. Any of the JavaScript controls require special handling for uploads which I'll also discuss in my next post.© Rick Strahl, West Wind Technologies, 2005-2012Posted in HTML5  ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Why does JAXB not create a member variable in its generated code when an XML schema base type and subtype have the same element declared in them?

    - by belltower
    I have a question regarding with regard to JAXB generated classes. As you can I see, I have a complex type, DG_PaymentIdentification1, declared in my schema. Its a restriction of PaymentIdentification1. DG_PaymentIdentification1 is also identical to PaymentIdentification1. I also have a type called DG_CreditTransferTransactionInformation10 which has a base type of CreditTransferTransactionInformation10 and is identical to it. I have included the relevant XML schema snippets below. <xs:complexType name="DG_PaymentIdentification1"> <xs:complexContent> <xs:restriction base="PaymentIdentification1"> <xs:sequence> <xs:element name="InstrId" type="DG_Max35Text_REF" minOccurs="0"/> <xs:element name="EndToEndId" type="DG_Max35Text_REF" id="DG-41"/> </xs:sequence> </xs:restriction> </xs:complexContent> </xs:complexType> <xs:complexType name="PaymentIdentification1"> <xs:sequence> <xs:element name="InstrId" type="Max35Text" minOccurs="0"/> <xs:element name="EndToEndId" type="Max35Text"/> </xs:sequence> </xs:complexType> <xs:complexType name="DG_CreditTransferTransactionInformation10"> <xs:complexContent> <xs:restriction base="CreditTransferTransactionInformation10"> <xs:sequence> <xs:element name="PmtId" type="DG_PaymentIdentification1"/> <xs:simpleType name="DG_Max35Text_REF"> <xs:restriction base="DG_NotEmpty35"> <xs:pattern value="[\-A-Za-z0-9\+/\?:\(\)\.,'&#x20;]*"/> </xs:restriction> </xs:simpleType> <xs:simpleType name="Max35Text"> <xs:restriction base="xs:string"> <xs:minLength value="1"/> <xs:maxLength value="35"/> </xs:restriction> </xs:simpleType> JAXB generates the following java class for DG_PaymentIdentification1: @XmlAccessorType(XmlAccessType.FIELD) @XmlType(name = "DG_CreditTransferTransactionInformDGion10") public class DGCreditTransferTransactionInformation10 extends CreditTransferTransactionInformation10 { } My question is why doesnt the DGCreditTransferTransactionInformation10 generated class have a variable of type DG_PaymentIdentification1 in the generated code? The base class CreditTransferTransactionInformation10 does have a type PaymentIdentification1 declared in it. Is there any way of ensuring that DGCreditTransferTransactionInformation10 will have a DG_PaymentIdentification1 in it?

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  • ephemeral vs EBS partitions

    - by hortitude
    I launched an EBS backed AMI with all the defaults. I noticed that it automicatlly had attached an ephemeral disk. I was just wondering if there was a good programtic way to know that this particular device is ephemeral vs some EBS volume I had decided to attach: ubuntu@-----:~$ df -ahT Filesystem Type Size Used Avail Use% Mounted on /dev/xvda1 ext4 7.9G 867M 6.7G 12% / proc proc 0 0 0 - /proc sysfs sysfs 0 0 0 - /sys none fusectl 0 0 0 - /sys/fs/fuse/connections none debugfs 0 0 0 - /sys/kernel/debug none securityfs 0 0 0 - /sys/kernel/security udev devtmpfs 1.9G 12K 1.9G 1% /dev devpts devpts 0 0 0 - /dev/pts tmpfs tmpfs 751M 172K 750M 1% /run none tmpfs 5.0M 0 5.0M 0% /run/lock none tmpfs 1.9G 0 1.9G 0% /run/shm /dev/xvdb ext3 394G 199M 374G 1% /mnt ubuntu@-----:~$ mount /dev/xvda1 on / type ext4 (rw) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) udev on /dev type devtmpfs (rw,mode=0755) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) /dev/xvdb on /mnt type ext3 (rw,_netdev)

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  • Is there a practical benefit to casting a NULL pointer to an object and calling one of its member fu

    - by zdawg
    Ok, so I know that technically this is undefined behavior, but nonetheless, I've seen this more than once in production code. And please correct me if I'm wrong, but I've also heard that some people use this "feature" as a somewhat legitimate substitute of a lacking aspect of the current C++ standard, namely, the inability to obtain the address (well, offset really) of a member function. For example, this is out of a popular implementation of a PCRE (Perl-compatible Regular Expression) library: #ifndef offsetof #define offsetof(p_type,field) ((size_t)&(((p_type *)0)->field)) #endif One can debate whether the exploitation of such a language subtlety in a case like this is valid or not, or even necessary, but I've also seen it used like this: struct Result { void stat() { if(this) // do something... else // do something else... } }; // ...somewhere else in the code... ((Result*)0)->stat(); This works just fine! It avoids a null pointer dereference by testing for the existence of this, and it does not try to access class members in the else block. So long as these guards are in place, it's legitimate code, right? So the question remains: Is there a practical use case, where one would benefit from using such a construct? I'm especially concerned about the second case, since the first case is more of a workaround for a language limitation. Or is it? PS. Sorry about the C-style casts, unfortunately people still prefer to type less if they can.

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