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How can I serialize this .NET Collection item?

- by Pure.Krome

Hi folks, I'm trying to xml serialize a POCO view data class into xml. It serializes, but incorrectly generates some xml. eg. (current result .. not the one I'm after) <ReviewListViewData> <reviews> <review>....</review> ... </reviews> </ReviewListViewData> I'm trying to get (notice how I've removed the bad root node?) ... <reviews> <review>....</review> ... </reviews> Class is defined as... public class ReviewListViewData { [XmlArray("reviews")] [XmlArrayItem("review")] public ReviewViewData[] Reviews { get; set; } } and here's a sample way it's called in an ASP.NET MVC ActionMethod :- var reviewListViewData = GetReviewListViewData(...); return XmlResult(reviewListViewData); // (XmlResult referenced from MVCContrib). anyone have any ideas, please?

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Keeping track of dependency revisions

- by Samaursa

I have a project with several dependencies that are in various repositories. Each time I commit changes to my project, I make sure I write the revision numbers of all the dependent repositories so that in the event I ever have to come back to this revision (let's call it 5), I can immediately know which revisions of the dependent repositories revision 5 is guaranteed to work with, update the dependencies to the specified revisions, compile and run the project. So for example if I have: Dep1 @ Revisions 10 Dep2 @ Revisions 20 Dep3 @ Revisions 10 Proj @ Revisions 35 And let's say that when Proj was on revision 17, the Dep1 revision was 5, Dep2 revision was 13 and Dep3 revision was 3. So in my SVN logs, I recorded something like this: !! Works with Dep1 Rev 5, Dep2 Rev 13, Dep3 Rev 3 To me this seems primitive and makes me believe that there is a better way to do it. Now in one of my other questions, Ivy Dependency Manager has been recommended. I have not looked at it in detail yet (seems complicated and yet another thing I must learn). To me it seems like the log of SVN (and Mercurial etc.) could have been split into Log and Dependencies (if any) where the latter could be switched off if there were no dependencies (unless of course I am unaware of an easier/better solution). This would allow for a cleaner log that maybe even warned at each new commit to check the previously defined dependencies again and make sure they have not changed. So, I was wondering how everyone manages this situations and if you have any tips, techniques, programs, suggestions that you can offer. Thank you.

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Using variables before include()ing them

- by phenry

I'm using a file, page.php, as an HTML container for several content files; i.e., page.php defines most of the common structure of the page, and the content files just contain the text that's unique to every page. What I would like to do is include some PHP code with each content file that defines metadata for the page such as its title, a banner graphic to use, etc. For example, a content file might look like this (simplified): <?php $page_title="My Title"; ?> <h1>Hello world!</h1> The name of the file would be passed as a URL parameter to page.php, which would look like this: <html> <head> <title><?php echo $page_title; ?></title> </head> <body> <?php include($_GET['page']); ?> </body> </html> The problem with this approach is that the variable gets defined after it is used, which of course won't work. Output buffering also doesn't seem to help. Is there an alternate approach I can use? I'd prefer not to define the text in the content file as a PHP heredoc block, because that smashes the HTML syntax highlighting in my text editor. I also don't want to use JavaScript to rewrite page elements after the fact, because many of these pages don't otherwise use JavaScript and I'd rather not introduce it as a dependency if I don't have to.

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What does "Select Distinct Null As xxxxx" mean?

- by Soylent Green

Background: I am mapping Sybase stored procedure return values to java objects using Spring. For example I map a Sybase datatype of varchar as a String type in Java, and a Sybase datatype of int as an int type in Java, etc. I have come across the following code in one of the stored procedures: SELECT DISTINCT A.Col1 AS val1, A.Col2 AS val2, NULL AS someVal, A.col3 AS val3, ... A.col9 AS val9 FROM #SomeTable A ORDER BY Col2, Col3 I have 2 related questions: What does Null mean in this scenario? I am confused as to what is happening here. I am able to determine the data type of Col1, Col2, etc. of course by looking at the table definition of Table A defined earlier in the stored procedure. Thus I know what datatype I can define in my Java object for val1, val2, etc.. But what about "someVal"? What datatype mapping am I supposed to perform for this Null value? I am fairly inexperienced in SQL. Perhaps the answer is much simpler than I realize.

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Is it bad practise to initialise fields outside of an explicit constructor

- by MrTortoise

So its monday and we are arguing about coding practises. The examples here are a litttle too simple, but the real deal has several constructors. In order to initialise the simple values (eg dates to their min value) I have moved the code out of the constructors and into the field definitions. public class ConstructorExample { string _string = "John"; } public class ConstructorExample2 { string _string; public ConstructorExample2() { _string = "John"; } } How should it be done by the book. I tend to be very case by case and so am maybe a little lax abotu this kind of thing. However i feel that accams razor tells me to move the initialisation out of multiple constructors. Of course I could always move this shared initialisation into a private method. The question is essentially ... is initialising fields where they are defined as opposed to the constructor bad in any way? The argument I am facing is one of error handling, but i do not feel it is relevant as there are no possible exceptions that won't be picked up at compile time.

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Best way reading from dirty excel sheets

- by Ten Ton Gorilla

I have to manipulate some Excel documents with C#. It's a batch process with no user interaction. It's going to parse data into a database, then output nice reports. The data is very dirty and cannot be ready using ADO. The data is nowhere near a nice table format. Best is defined as the most stable(updates less likely to break)/ clear(succinct) code. Fast doesn't matter. If it runs in less than 8 hours I'm fine. I have the logic to find the data worked out. All I need to make it run is basic cell navigation and getvalue type functions. Give me X cell value as string, if it matches Y value with levenshtein distance < 3, then give me Z cell value. My question is, what is the best way to dig into the excel? VSTO? Excel Objects Library? Third Option I'm not aware of?

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Design by contracts and constructors

- by devoured elysium

I am implementing my own ArrayList for school purposes, but to spice up things a bit I'm trying to use C# 4.0 Code Contracts. All was fine until I needed to add Contracts to the constructors. Should I add Contract.Ensures() in the empty parameter constructor? public ArrayList(int capacity) { Contract.Requires(capacity > 0); Contract.Ensures(Size == capacity); _array = new T[capacity]; } public ArrayList() : this(32) { Contract.Ensures(Size == 32); } I'd say yes, each method should have a well defined contract. On the other hand, why put it if it's just delegating work to the "main" constructor? Logicwise, I wouldn't need to. The only point I see where it'd be useful to explicitly define the contract in both constructors is if in the future we have Intelisense support for contracts. Would that happen, it'd be useful to be explicit about which contracts each method has, as that'd appear in Intelisense. Also, are there any books around that go a bit deeper on the principles and usage of Design by Contracts? One thing is having knowledge of the syntax of how to use Contracts in a language (C#, in this case), other is knowing how and when to use it. I read several tutorials and Jon Skeet's C# in Depth article about it, but I'd like to go a bit deeper if possible. Thanks

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Using C struct without including header file

- by shams

My basic problem is that I want to use some structs and functions defined in a header file by not including that header file in my code. The header file is generated by a tool. Since I don't have access to the header file, I can't include it in my program. Here's a simple example of my scenario: first.h #ifndef FIRST_H_GUARD #define FIRST_H_GUARD typedef struct ComplexS { float real; float imag; } Complex; Complex add(Complex a, Complex b); // Other structs and functions #endif first.c #include "first.h" Complex add(Complex a, Complex b) { Complex res; res.real = a.real + b.real; res.imag = a.imag + b.imag; return res; } my_program.c // I cannot/do not want to include the first.h header file here // but I want to use the structs and functions from the first.h #include <stdio.h> int main() { Complex a; a.real = 3; a.imag = 4; Complex b; b.real = 6; b.imag = 2; Complex c = add(a, b); printf("Result (%4.2f, %4.2f)\n", c.real, c.imag); return 0; } My intention is to build an executable for my_program and then use the linker to link up the executables. Is what I want to achieve possible in C?

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My project is no longer used - how should I feel?

- by flybywire

For the last two years I have been developing and supporting an important project for a big customer. The project included mining data from the customer's existing systems, processing, and displaying and updating in the customer's public home page. The project was defined as crucial by the customer and I was payed good money and flown at the customer's expense to meet key employees. Some months ago, when the project was finished and in maintainance mode, I informed the customer that I am no longer interested in doing it as I had a new opportunity that would not be compatible with my existing customer. I was payed to train one of their employees, flown to meet him, make sure everything works and that he can be safely left in charge of the project. We finished in good terms after I complied with all my obligations and they payed me all they owed me. Some days ago, just out of curiosity, I entered to their website to see how the data continues to be updated and much to my dismay I discovered that the day after my contract was finished my system was "turned off" and it ceased to feed data to the public website. Let's put it clear, there is no issue of money or broken contract here. They are in they full right to do whatever they want with my software. But it is an issue of broken "programmer's ego". Should I feel bad about it (I do). Should I care and check out with my customer if they need some help? Or is it none of my matters?

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Are TestContext.Properties usable ?

- by DBJDBJ

Using Visual Studio generate Test Unit class. Then comment in, the class initialization method. Inside it add your property, using the testContext argument. Upon test app startup this method is indeed called by the testing infrastructure. //Use ClassInitialize to run code before running the first test in the class [ClassInitialize()] public static void MyClassInitialize(TestContext testContext) { /* * Any user defined testContext.Properties * added here will be erased after this method exits */ testContext.Properties.Add("key", 1 ) ; // place the break point here } After leaving MyClassInitialize, any properties added by user are lost. Only the 10 "official" ones are left. Actually TestContext gets overwritten, with the inital offical one, each time before each test method is called. It it not overwritten only if user has test initialization method, the changes made over there are passed to the test. //Use TestInitialize to run code before running each test [TestInitialize()]public void MyTestInitialize(){ this.TestContext.Properties.Add("this is preserved",1) ; } This effectively means TestContext.Properties is "mostly" read only, for users. Which is not clearly documented in MSDN. It seems to me this is very messy design+implementation. Why having TestContext.Properties as an collection, at all ? Users can do many other solutions to have class wide initialization. Please discuss. --DBJ

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How to define 2-bit numbers in C, if possible?

- by Eddy

For my university process I'm simulating a process called random sequential adsorption. One of the things I have to do involves randomly depositing squares (which cannot overlap) onto a lattice until there is no more room left, repeating the process several times in order to find the average 'jamming' coverage %. Basically I'm performing operations on a large array of integers, of which 3 possible values exist: 0, 1 and 2. The sites marked with '0' are empty, the sites marked with '1' are full. Initially the array is defined like this: int i, j; int n = 1000000000; int array[n][n]; for(j = 0; j < n; j++) { for(i = 0; i < n; i++) { array[i][j] = 0; } } Say I want to deposit 5*5 squares randomly on the array (that cannot overlap), so that the squares are represented by '1's. This would be done by choosing the x and y coordinates randomly and then creating a 5*5 square of '1's with the topleft point of the square starting at that point. I would then mark sites near the square as '2's. These represent the sites that are unavailable since depositing a square at those sites would cause it to overlap an existing square. This process would continue until there is no more room left to deposit squares on the array (basically, no more '0's left on the array) Anyway, to the point. I would like to make this process as efficient as possible, by using bitwise operations. This would be easy if I didn't have to mark sites near the squares. I was wondering whether creating a 2-bit number would be possible, so that I can account for the sites marked with '2'. Sorry if this sounds really complicated, I just wanted to explain why I want to do this.

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Is there an alias for 'this' in TypeScript?

- by Todd

I've attempted to write a class in TypeScript that has a method defined which acts as an event handler callback to a jQuery event. class Editor { textarea: JQuery; constructor(public id: string) { this.textarea = $(id); this.textarea.focusin(onFocusIn); } onFocusIn(e: JQueryEventObject) { var height = this.textarea.css('height'); // <-- This is not good. } } Within the onFocusIn event handler, TypeScript sees 'this' as being the 'this' of the class. However, jQuery overrides the this reference and sets it to the DOM object associated with the event. One alternative is to define a lambda within the constructor as the event handler, in which case TypeScript creates a sort of closure with a hidden _this alias. class Editor { textarea: JQuery; constructor(public id: string) { this.textarea = $(id); this.textarea.focusin((e) => { var height = this.textarea.css('height'); // <-- This is good. }); } } My question is, is there another way to access the this reference within the method-based event handler using TypeScript, to overcome this jQuery behavior?

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JQuery - Set TBODY

- by Villager

Hello, I have a table defined as follows: <table id="myTable" cellpadding="0" cellspacing="0"> <thead><tr> <th>Date</th> <th>First Name</th> <th>Last Name</th> </tr></thead> <tbody>  </tbody> </table> I am trying to dynamically populate 'myTable' at runtime via JavaScript. To accomodate for this, I am using JQuery. I want to write some HTML into the tbody element within 'myTable'. However, I am having problems understanding how to do this with the selectors. I know that I can get 'myTable' using: $("#myTable") I know that I can set the HTML of myTable by using the following: $("#myTable").html(someHtmlString); However, that sets the HTML of the entire table. In reality, I just want to set the HTML within the TBODY of 'myTable'. How do I do this with JQuery? Thank you!

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SQL Server 2008 - Full Text Query

- by user208662

Hello, I have two tables in a SQL Server 2008 database in my company. The first table represents the products that my company sells. The second table contains the product manufacturer’s details. These tables are defined as follows: Product ------- ID Name ManufacturerID Description Manufacturer ------------ ID Name As you can imagine, I want to make this as easy as possible for our customers to query this data. However, I’m having problems writing a forgiving, yet powerful search query. For instance, I’m anticipating people to search based on phonetical spellings. Because of this, the data may not match the exact data in my database. In addition, I think some individuals will search by manufacturer’s name first, but I want the matching product names to appear first. Based on these requirements, I’m currently working on the following query: select p.Name as 'ProductName', m.Name as 'Manufacturer', r.Rank as 'Rank' from Product p inner join Manufacturer m on p.ManufacturerID=m.ID inner join CONTAINSTABLE(Product, Name, @searchQuery) as r Oddly, this query is throwing an error. However, I have no idea why. Squiggles appear to the right of the last parenthesis in management studio. The tool tip says "An expression of non-boolean type specified in a context where a condition is expected". I understand what this statement means. However, I guess I do not know how COntainsTable works. What am I doing wrong? Thank you

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Web Applications Development: Security practices for Application design

- by Shyam

Hi, As I am creating more web applications that are targeted for multiple users, I figured out that I have to start thinking about user management and security. At a glance and in my ideal world, all users belong to a group. Permissions and access is thus defined per group (and inherited by the users of that group). Logically, I have my group of administrators, which are identified with a level "7" (integer) clearance. A group of webusers have for example level "1". This in generally all works great for me, but I need some kind of list that I have to keep in mind how I secure my system, and some general practices. I am not looking for a specific environment; I want to learn the why's and how's. An example is privilege escalation. If someone would be able to "push" themselves inside a group with higher privileges, for example the Administration, how can I prevent this, or what measures should I take to have some sort of precaution? I don't like in that case to walk into a caveat. My question is basically: where can I find a good resource, list, policy, book that explains the security of web applications, the why's, the how's and readable if you don't have any experience in the realm of advanced security? I prefer a free resource, as I believe I couldn't be the first one who thought about this. Thank you for your answers, comments and feedback.

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How to take a collection of bytes and pull typed values out of it?

- by Pat

Say I have a collection of bytes var bytes = new byte[] {0, 1, 2, 3, 4, 5, 6, 7}; and I want to pull out a defined value from the bytes as a managed type, e.g. a ushort. What is a simple way to define what types reside at what location in the collection and pull out those values? One (ugly) way is to use System.BitConverter and a Queue or byte[] with an index and simply iterate through, e.g.: int index = 0; ushort first = System.BitConverter.ToUint16(bytes, index); index += 2; // size of a ushort int second = System.BitConverter.ToInt32(bytes, index); index += 4; ... This method gets very, very tedious when you deal with a lot of these structures! I know that there is the System.Runtime.InteropServices.StructLayoutAttribute which allows me to define the locations of types inside a struct or class, but there doesn't seem to be a way to import the collection of bytes into that struct. If I could somehow overlay the struct on the collection of bytes and pull out the values, that would be ideal. E.g. Foo foo = (Foo)bytes; // doesn't work because I'd need to implement the implicit operator ushort first = foo.first; int second = foo.second; ... [StructLayout(LayoutKind.Explicit, Size=FOO_SIZE)] public struct Foo { [FieldOffset(0)] public ushort first; [FieldOffset(2)] public int second; } Any thoughts on how to achieve this?

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negative values in integer programming model

- by Lucia

I'm new at using the glpk tool, and after writing a model for certain integer problem and running the solver (glpsol) i get negative values in some constraint that shouldn't be negative at all: No.Row name Activity Lower bound Upper bound 8 act[1] 0 -0 9 act[2] -3 -0 10 act[2] -2 -0 That constraint is defined like this: act{j in J}: sum{i in I} d[i,j] <= y[j]*m; where the sets and variables used are like this: param m, integer, 0; param n, integer, 0; set I := 1..m; set J := 1..n; var y{j in J}, binary; As the upper bound is negative, i think the problem may be in the y[j]*m parte, of the right side of the inequality.. perhaps something with the multiplication of binarys? or that the j in that side of the constrait is undefined? i dont know... i would be greatly grateful if someone can help me with this! :) and excuse for my bad english thanks in advance!

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.NET port with Java's Map, Set, HashMap

- by Nikos Baxevanis

I am porting Java code in .NET and I am stuck in the following lines that (behave unexpectedly in .NET). Java: Map<Set<State>, Set<State>> sets = new HashMap<Set<State>, Set<State>>(); Set<State> p = new HashSet<State>(); if (!sets.containsKey(p)) { ... } The equivalent .NET code could possibly be: IDictionary<HashSet<State>, HashSet<State>> sets = new Dictionary<HashSet<State>, HashSet<State>>(); HashSet<State> p = new HashSet<State>(); if (!sets.containsKey(p)) { /* (Add to a list). Always get here in .NET (??) */ } However the code comparison fails, the program think that "sets" never contain Key "p" and eventually results in OutOfMemoryException. Perhaps I am missing something, object equality and identity might be different between Java and .NET. I tried implementing IComparable and IEquatable in class State but the results were the same. Edit: What the code does is: If the sets does not contain key "p" (which is a HashSet) it is going to add "p" at the end of a LinkedList. The State class (Java) is a simple class defined as: public class State implements Comparable<State> { boolean accept; Set<Transition> transitions; int number; int id; static int next_id; public State() { resetTransitions(); id = next_id++; } // ... public int compareTo(State s) { return s.id - id; } public boolean equals(Object obj) { return super.equals(obj); } public int hashCode() { return super.hashCode(); }

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Change Sequence to Choice

- by Gordon

In my Schema File I defined a Group with a Sequence of possible Elements. <group name="argumentGroup"> <sequence> <element name="foo" type="double" /> <element name="bar" type="string" /> <element name="baz" type="integer" /> </sequence> </group> I then reference this Group like this: <element name="arguments"> <complexType> <group ref="my:argumentGroup"/> </complexType> </element> Is it possible to reference the Group at some other point but restrict it so it's a Choice instead of a Sequence. The position where I want to reuse it would only allow one of the Elements within. <element name="argument" minOccurs="0" maxOccurs="1"> <complexType> <group name="my:argumentGroup"> <! -- Somehow change argumentGroup sequence to choice here --> </group> <complexType> </element>

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python recursive iteration exceeding limit for tree implementation

- by user3698027

I'm implementing a tree dynamically in python. I have defined a class like this... class nodeobject(): def __init__(self,presentnode=None,parent=None): self.currentNode = presentnode self.parentNode = parent self.childs = [] I have a function which gets possible childs for every node from a pool def findchildren(node, childs): # No need to write the whole function on how it gets childs Now I have a recursive function that starts with the head node (no parent) and moves down the chain recursively for every node (base case being the last node having no children) def tree(dad,children): for child in children: childobject = nodeobject(child,dad) dad.childs.append(childobject) newchilds = findchildren(child, children) if len(newchilds) == 0: lastchild = nodeobject(newchilds,childobject) childobject.childs.append(lastchild) loopchild = copy.deepcopy(lastchild) while loopchild.parentNode != None: print "last child" else: tree(childobject,newchilds) The tree formation works for certain number of inputs only. Once the pool gets bigger, it results into "MAXIMUM RECURSION DEPTH EXCEEDED" I have tried setting the recursion limit with set.recursionlimit() and it doesn't work. THe program crashes. I want to implement a stack for recursion, can someone please help, I have gone no where even after trying for a long time ?? Also, is there any other way to fix this other than stack ?

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Visual Studio 2008 linker wants all symbols to be resolved, not only used ones

- by user343011

We recently upgraded to Visual Studio 2008 from 2005, and I think those error started after that. In our solution, we have a multitude of projects. Many of those are utility projects, or projects containing core functionality used by other projects. The output of those is lib files that are linked to when building the projects generating the final binaries using the "Project dependencies..." option. One of the other projects---Let us call it ResultLib---generates a DLL, and it needs one single function from the core project. This function uses only static function from its own source file, but the project in its entirety uses a lot of low-level Windows functions and also imports a DLL---Let us call it Driver.dll. Our problem is that when building ExtLib, the linker complains about a multitude of unresolved externals, for example all functions exported from Driver.dll, since its lib file is not specified when linking. If we try to fix this by adding all lib files used by other projects that use all of the core project, our resulting ResultLib DLL ends up importing Driver.dll and also exporting all functions defined in it. How do we tell Visual Studio to only try to resolve symbols that are actually used?

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How to limit TCP writes to particular size and then block untlil the data is read

- by ustulation

{Qt 4.7.0 , VS 2010} I have a Server written in Qt and a 3rd party client executable. Qt based server uses QTcpServer and QTcpSocket facilities (non-blocking). Going through the articles on TCP I understand the following: the original implementation of TCP mentioned the negotiable window size to be a 16-bit value, thus maximum being 65535 bytes. But implementations often used the RFC window-scale-extension that allows the sliding window size to be scalable by bit-shifting to yield a maximum of 1 gigabyte. This is implementation defined. This could have resulted in majorly different window sizes on receiver and sender end as the server uses Qt facilities without hardcoding any window size limit. Client 1st asks for all information it can based on the previous messages from the server before handling the new (accumulating) incoming messages. So at some point Server receives a lot of messages each asking for data of several MB's. This the server processes and puts it into the sender buffer. Client however is unable to handle the messages at the same pace and it seems that client’s receiver buffer is far smaller (65535 bytes maybe) than sender’s transmit window size. The messages thus get accumulated at sender’s end until the sender’s buffer is full too after which the TCP writes on sender would block. This however does not happen as sender buffer is much larger. Hence this manifests as increase in memory consumption on the sender’s end. To prevent this from happening, I used Qt’s socket’s waitForBytesWritten() with timeout set to -1 for infinite waiting period. This as I see from the behaviour blocks the thread writing TCP data until the data has actually been sensed by the receiver’s window (which will happen when earlier messages have been processed by the client at application level). This has caused memory consumption at Server end to be almost negligible. is there a better alternative to this (in Qt) if i want to restrict the memory consumption at server end to say x MB's? Also please point out if any of my understandings is incorrect.

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Javascript: click and dblclick deliver different parentNodes on same html. Why?

- by user1658206

currently I work on an very small wysiwyg editor based on jquery. I dont care about IE oder Chrome, just Firefox. My problem is to find if the selection is in a link for to get the value of the href attribute if is set. With click the node of the link is found, with double click always the body. It is in designMode. My event-handler for click and dblclick. The vars current_selection, current_node, iframe and container are global. selection_handler:function() { current_selection = iframe.getSelection(); current_node = current_selection.anchorNode; if(current_node.nodeName == "#text") { current_node = current_node.parentNode; } $('#log').text(current_node.nodeName); }, The log shows mit for example 'body', when I click in unformated text. When I add a link with execCommand('createLink',...) the log shows 'A'. That works. When I mark the linked word with 2 click from start to end, the log shows 'A'. But with double click I always get 'body'. So I can't get the href attribute. The handler is defined in the init: init:function(options) { ... iframe = $('#wysiwyg-'+container.attr('id'))[0].contentWindow; iframe.addEventListener('dblclick',methods.selection_handler,false); iframe.addEventListener('click',methods.selection_handler,false); ... } Has somebody an idea what is wrong?

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How can I include DBNull as a value in my strongly typed dataset?

- by Beska

I've created a strongly typed dataset (MyDataSet) in my .NET app. For the sake of simplicity, we'll say it has one DataTable (MyDataTable), with one column (MyCol). MyCol has its DataType property set to "System.Int32", and its AllowDBNull property set to "true". I'd like to manually create a new row, and add it to this dataset. I create the row without a problem, with something like: MyDataSet.MyDataTableRow myRow = MySimpleDataSet.MyDataTable.NewItemRow(); Fine. However, when I try to set the value to DBNull: myRow.MyCol = DBNull.Value; I'm told that I can't do it...that it can't cast that to an int. This makes sense, in a way, since I've defined it to be an int...but then how can I get DBNull in there? Am I not supposed to be able to have DBNull in there? Isn't that what the AllowDBNull property is for? I'm obviously missing something fundemental. Can someone help explain what it is? EDIT: I also tried entering "int?" as the DataType, but Visual Studio throws an error when I enter it, saying that "Column requires a valid DataType."

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C++ -- Why should we use operator -> to access member functions of a SmartPtr?

- by q0987

Hello all, The question is given in the last two lines of code. template<class T> // template class for smart class SmartPtr { // pointers-to-T objects public: SmartPtr(T* realPtr = 0); T* operator->() const; T& operator*() const; T* Detach( void ) { T* pData = pointee; pointee = NULL; return pData; } private: T *pointee; ... }; class TestClass {} SmartPtr<TestClass> sPtr(new TestClass); TestClass* ptrA = sPtr->Detach(); // why I always see people use this method to access member functions of a Smart pointer. We can use sPtr-> b/c we have defined operator->() in SmartPtr. TestClass* ptrB = sPtr.Detach(); // Question: Is this a valid C++ way? If not, why? Thank you

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