ken jackson - Page 19 - Developer IT

When is the cached Page class updated and rebuilt?

- by Ken

When is the cached Page class updated and rebuilt?

How to populate Range variable from a Sub/Function call?

I am trying to get this sub to work but the operationalRange variable is not being assigned. Despite the fact that the function selectBodyRow(bodyName) works fine. Sub sortRows(bodyName As String, ByRef wksht As Worksheet) Dim operationalRange As Range Set operationalRange = selectBodyRow(bodyName) Debug.Print "Sorting Worksheet: " & wksht.Name If Not operationalRange Is Nothing Then operationalRange.Select Debug.Print "Sorting " & operationalRange.Count & "Rows." ActiveWorkbook.Worksheets(wksht.Name).Sort.SortFields.Clear ActiveWorkbook.Worksheets(wksht.Name).Sort.SortFields.Add Key:=operationalRange, _ SortOn:=xlSortOnValues, Order:=xlAscending, DataOption:=xlSortNormal ActiveWorkbook.Worksheets(wksht.Name).Sort.SortFields.Add Key:=operationalRange, _ SortOn:=xlSortOnValues, Order:=xlAscending, DataOption:=xlSortNormal With ActiveWorkbook.Worksheets(wksht.Name).Sort .SetRange operationalRange .Header = xlGuess .MatchCase = False .Orientation = xlTopToBottom .SortMethod = xlPinYin .Apply End With Else MsgBox "Body is not being Set" End If End Sub The Sub being called by the above Sub is: Function selectBodyRow(bodyName As String) As Range Dim rangeStart As String, rangeEnd As String Dim selectionStart As Range, selectionEnd As Range Dim result As Range, srchRng As Range, cngrs As Variant If bodyName = "WEST" Then rangeStart = "<-WEST START->" rangeEnd = "<-WEST END->" ElseIf bodyName = "EAST" Then rangeStart = "<-EAST START->" rangeEnd = "<-EAST END->" End If Set srchRng = Range("A:A") srchRng.Select Set selectionStart = srchRng.Find(What:=rangeStart, After:=ActiveCell, LookIn _ :=xlValues, LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:= _ xlNext, MatchCase:=False, SearchFormat:=False) Set selectionEnd = srchRng.Find(What:=rangeEnd, After:=ActiveCell, LookIn _ :=xlValues, LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:= _ xlNext, MatchCase:=False, SearchFormat:=False) Set result = Range(selectionStart.Offset(1, 0), selectionEnd.Offset(-1, 0)) result.EntireRow.Select End Function

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Need help converting SQL to EF4 please

- by Ken Eldridge

I need help converting this SQL statement, into EF4: Select Posts.PostID, Post, Comment from Posts left join Comments on posts.PostID = Comments.PostID Where CommentID not in ( Select PostID from Votes where VoteTypeID = 4 --4 = flagged comment type ) In my database, the Votes table stores either the PostID of reported posts, or CommentID of reported comments in the column Votes.PostID Thanks in advance!

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Run-time error 459 when using WithEvents with a class that implements another

- by Ken Keenan

I am developing a VBA project in Word and have encountered a problem with handling events when using a class that implements another. I define an empty class, IMyInterface: Public Sub Xyz() End Sub Public Event SomeEvent() And a class, MyClass that implements the above: Implements IMyInterface Public Event SomeEvent() Public Sub Xyz() ' ... code ... RaiseEvent SomeEvent End Sub Private Sub IMyInterface_Xyz() Xyz End Sub If I create a third class, OtherClass, that declares a member variable with the type of the interface class: Private WithEvents mMy As IMyInterface and try to initialize this variable with an instance of the implementing class: Set mMy = New MyClass I get a run-time error '459': This component doesn't support this set of events. The MSDN page for this error message states: "You tried to use a WithEvents variable with a component that can't work as an event source for the specified set of events. For example, you may be sinking events of an object, then create another object that Implements the first object. Although you might think you could sink the events from the implemented object, that isn't automatically the case. Implements only implements an interface for methods and properties." The above pretty much sums up what I'm trying to do. The wording, "that isn't automatically the case", rather than "this is flat-out impossible", seems to suggest that there is some bit of manual work I need to do to get it to work, but it doesn't tell me what! Does anybody know if this is possible in VBA?

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How to select the most recent set of dated records from a mysql table

- by Ken

I am storing the response to various rpc calls in a mysql table with the following fields: Table: rpc_responses timestamp (date) method (varchar) id (varchar) response (mediumtext) PRIMARY KEY(timestamp,method,id) What is the best method of selecting the most recent responses for all existing combinations of method and id? For each date there can only be one response for a given method/id. Not all call combinations are necessarily present for a given date. There are dozens of methods, thousands of ids and at least 356 different dates Sample data: timestamp method id response 2009-01-10 getThud 16 "....." 2009-01-10 getFoo 12 "....." 2009-01-10 getBar 12 "....." 2009-01-11 getFoo 12 "....." 2009-01-11 getBar 16 "....." Desired result: 2009-01-10 getThud 16 "....." 2009-01-10 getBar 12 "....." 2009-01-11 getFoo 12 "....." 2009-01-11 getBar 16 "....." (I don't think this is the same question - it won't give me the most recent response)

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Abstract classes and Pod::Coverage

- by Ken Williams

I've recently started to try to use Dist::Zilla for maintaining Path::Class. I added the [PodCoverageTests] plugin, and it's reporting some failures in the Path::Class::Entity class, which is the abstract base class for Path::Class::File and Path::Class::Dir. What I'd like is some way to tell the testing code that Entity doesn't need docs, but its two derived classes do - even though the methods are only defined in the parent class. Anyone know some way to do that?

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"Inherited" types in C++

- by Ken Moynihan

The following code does not compile. I get an error message: error C2039: 'Asub' : is not a member of 'C' Can someone help me to understand this? Tried VS2008 & 2010 compiler. template <class T> class B { typedef int Asub; public: void DoSomething(typename T::Asub it) { } }; class C : public B<C> { public: typedef int Asub; }; class A { public: typedef int Asub; }; int _tmain(int argc, _TCHAR* argv[]) { C theThing; theThing.DoSomething(C::Asub()); return 0; }

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Using $this when not in object context

- by Ken

I'm creating a function to show blog's. So I made a show blog function but it keeps giving "Using $this when not in object context" error Class Blog{ public function getLatestBlogsBig($cat = null){ $sqlString = "SELECT blog_id FROM jab_blog"; if($cat != null) $sqlString .= " WHERE blog_cat = " . $cat; $sqlString .= " ORDER BY blog_id DESC LIMIT 5"; $blog = mysql_query($sqlString); while($id = mysql_result($blog,"blog_id")){ $this->showBlog($id); //Error is on this line } } function showBlog($id,$small = false){ $sqlString = "SELECT blog_id FROM jab_blog WHERE blog_id=" . $id . ";"; $blog = mysql_query($sqlString); if($small = true){ echo "<ul>"; while($blogItem = mysql_fetch_array($blog)){ echo '<a href="' . $_SESSION['JAB_LINK'] . "blog/" . $blogItem['blog_id'] . "/" . SimpleUrl::toAscii($blogItem['blog_title']) .'">' . $blogItem['blog_title'] . '</a></li>'; } echo "</ul>"; }else{ while($blogItem = mysql_fetch_array($blog)){ ?> <div class="post"> <h2 class="title"><a href="<?php echo $_SESSION['JAB_LINK'] . "blog/" . $blogItem['blog_id'] . "/" . SimpleUrl::toAscii($blogItem['blog_title']);?>"><?php echo $blogItem['blog_title'];?></a></h2> <p class="meta"><span class="date">The date implement</span><span class="posted">Posted by <a href="#">Someone</a></span></p> <div style="clear: both;"> </div> <div class="entry"> <?php echo $blogItem['blog_content'];?> </div> </div> <?php } } } }

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I can't insert data into my database

- by Ken

I don't know why, but my data doesn't go into my database 'users' with the table 'data'. <html> <body> <?php date_default_timezone_set("America/Los_Angeles"); include("mainmenu.php"); $con = mysql_connect("localhost", "root", "g00dfor@boy"); if(!$con){ die(mysql_error()); } $usrname = $_POST['usrname']; $fname = $_POST['fname']; $lname = $_POST['lname']; $password = $_POST['password']; $email = $_POST['email']; mysql_select_db(`users`, $con) or die(mysql_error()); mysql_query(INSERT INTO `users`.`data` (`id`, `usrname`, `fname`, `lname`, `email`, `password`) VALUES (NULL, '$usrname', '$fname', '$lname', '$email', 'password')) or die(mysql_error()); mysql_close($con) echo("Thank you for registering!"); ?> </body> </html> All i get is a blank page.

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Error with MySQL Query

- by Ken

Okay, I must be an idiot, because this is my 3rd question for today. Here's my code: date_default_timezone_set("America/Los_Angeles"); include("mainmenu.php"); $con = mysql_connect("localhost", "root", "********"); if(!$con){ die(mysql_error()); } $usrname = $_POST['usrname']; $fname = $_POST['fname']; $lname = $_POST['lname']; $password = $_POST['password']; $email = $_POST['email']; mysql_select_db("`users`, $con) or die(mysql_error()"); $query = ("INSERT INTO `users`.`data` (`id`, `usrname`, `fname`, `lname`, `email`, `password`) VALUES (NULL, '$usrname', '$fname', '$lname', '$email', 'password'))"); mysql_query('$query') or die(mysql_error()); mysql_close($con); echo("Thank you for registering!"); I always get the error returned as: "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '$query' at line 1. Help a newbie. I'm about to stab my monitor.

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how do I best create a set of list classes to match my business objects

- by ken-forslund

I'm a bit fuzzy on the best way to solve the problem of needing a list for each of my business objects that implements some overridden functions. Here's the setup: I have a baseObject that sets up database, and has its proper Dispose() method All my other business objects inherit from it, and if necessary, override Dispose() Some of these classes also contain arrays (lists) of other objects. So I create a class that holds a List of these. I'm aware I could just use the generic List, but that doesn't let me add extra features like Dispose() so it will loop through and clean up. So if I had objects called User, Project and Schedule, I would create UserList, ProjectList, ScheduleList. In the past, I have simply had these inherit from List< with the appropriate class named and then written the pile of common functions I wanted it to have, like Dispose(). this meant I would verify by hand, that each of these List classes had the same set of methods. Some of these classes had pretty simple versions of these methods that could have been inherited from a base list class. I could write an interface, to force me to ensure that each of my List classes has the same functions, but interfaces don't let me write common base functions that SOME of the lists might override. I had tried to write a baseObjectList that inherited from List, and then make my other Lists inherit from that, but there are issues with that (which is really why I came here). One of which was trying to use the Find() method with a predicate. I've simplified the problem down to just a discussion of Dispose() method on the list that loops through and disposes its contents, but in reality, I have several other common functions that I want all my lists to have. What's the best practice to solve this organizational matter?

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Assembly GDB Print String

- by Ken

So in assembly I declare the following String: Sample db "This is a sample string",0 In GDB I type "p Sample" (without quotes) and it spits out 0x73696854. I want the actual String to print out. So I tried "printf "%s", Sample" (again, without quotes) and it spits out "Cannot access memory at address 0x73696854." Short version: How do I print a string in GDB?

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public class ImageHandler : IHttpHandler

- by Ken

cmd.Parameters.AddWithValue("@id", new system.Guid (imageid)); What using System reference would this require? Here is the handler: using System; using System.Collections.Specialized; using System.Web; using System.Web.Configuration; using System.Web.Security; using System.Globalization; using System.Configuration; using System.Data.SqlClient; using System.Data; using System.IO; using System.Web.Profile; using System.Drawing; public class ImageHandler : IHttpHandler { public void ProcessRequest(HttpContext context) { string imageid; if (context.Request.QueryString["id"] != null) imageid = (context.Request.QueryString["id"]); else throw new ArgumentException("No parameter specified"); context.Response.ContentType = "image/jpeg"; Stream strm = ShowProfileImage(imageid.ToString()); byte[] buffer = new byte[8192]; int byteSeq = strm.Read(buffer, 0, 8192); while (byteSeq > 0) { context.Response.OutputStream.Write(buffer, 0, byteSeq); byteSeq = strm.Read(buffer, 0, 8192); } //context.Response.BinaryWrite(buffer); } public Stream ShowProfileImage(String imageid) { string conn = ConfigurationManager.ConnectionStrings["MyConnectionString1"].ConnectionString; SqlConnection connection = new SqlConnection(conn); string sql = "SELECT image FROM Profile WHERE UserId = @id"; SqlCommand cmd = new SqlCommand(sql, connection); cmd.CommandType = CommandType.Text; cmd.Parameters.AddWithValue("@id", new system.Guid (imageid));//Failing Here!!!! connection.Open(); object img = cmd.ExecuteScalar(); try { return new MemoryStream((byte[])img); } catch { return null; } finally { connection.Close(); } } public bool IsReusable { get { return false; } } }

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Publish Git repository to SVN

- by Ken Williams

I and my small team work in Git, and the larger group uses Subversion. I'd like to schedule a cron job to publish our repositories current HEADs every hour into a certain directory in the SVN repo. I thought I had this figured out, but the recipe I wrote down previously doesn't seem to be working now: git clone ssh://me@gitserver/git-repo/Projects/ProjX px2 cd px2 svn mkdir --parents http://me@svnserver/svn/repo/play/me/fromgit/ProjX git svn init -s http://me@svnserver/svn/repo/play/me/fromgit/ProjX git svn fetch git rebase trunk master git svn dcommit Here's what happens when I attempt: % git clone ssh://me@gitserver/git-repo/Projects/ProjX px2 Cloning into 'ProjX'... ... % cd px2 % svn mkdir --parents http://me@svnserver/svn/repo/play/me/fromgit/ProjX Committed revision 123. % git svn init -s http://me@svnserver/svn/repo/play/me/fromgit/ProjX Using higher level of URL: http://me@svnserver/svn/repo/play/me/fromgit/ProjX => http://me@svnserver/svn/repo % git svn fetch W: Ignoring error from SVN, path probably does not exist: (160013): Filesystem has no item: File not found: revision 100, path '/play/me/fromgit/ProjX' W: Do not be alarmed at the above message git-svn is just searching aggressively for old history. This may take a while on large repositories % git rebase trunk master fatal: Needed a single revision invalid upstream trunk I could have sworn this worked previously, anyone have any suggestions? Thanks.

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Is there a way for -webkit-animtion-timing-function to apply to the entire animation instead of each keyframe?

- by Ken Sykora

I'm a bit new to animation, so forgive me if I'm missing a huge concept here. I need to animate an arrow that is pointing to a point on a curve, let's just say it's a cubic curve for the sake of this post. The arrow moves along the curve's line, always pointing a few pixels below it. So what I did, is I setup keyframes along the curve's line using CSS3: @-webkit-keyframes ftch { 0% { opacity: 0; left: -10px; bottom: 12px; } 25% { opacity: 0.25; left: 56.5px; bottom: -7px; } 50% { opacity: 0.5; left: 143px; bottom: -20px; } 75% { opacity: 0.75; left: 209.5px; bottom: -24.5px; } 100% { opacity: 1; left: 266px; bottom: -26px; } } However, when I run this animation using -webkit-animation-timing-function: ease-in, it applies that easing to each individual keyframe, which is definitely not what I want. I want the easing to apply to the entire animation. Is there a different way that I should be doing this? Is there some property to apply the easing to the entire sequence rather than each keyframe?

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Suggestions for a good IDE for DB2

- by ken

Hi all, I know, I know... it's a horrible fate but I am forced to work in an environment with DB2 on the back end. OK just kidding but the truth is I do like MSSQL's data studio a lot, and well IBM's tool is sorda crummy in my opinion... I was using the free version of Toad but I just got a new 64bit machine which is nice and all but there isn't a free version of Toad that I can find for win7 64. Does anyone have any suggestions for a good IDE to use with DB2? Being a developer I really just do a lot of looking at the DB structure and querying to see what I get back and how I want to get things back etc... Thanks for any advice!

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Iterating through child components

- by ken

I have button-group component which contains a set of button-element components. The template is defined as: {{#each buttons}} {{button-element titleBinding="title" action="buttonAction"}} {{/each}} I'd like the buttonAction() method in the button-group component to have easy access to the set of button-element components and iterate through them. What's the easiest way to do this? I know I could use a jQuery/DOM approach like: this.$('.btn').doSomething(); But I'd like to address the component objects not the DOM directly.

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PHP Form multiple buttons

- by Ken

I have a form with 2 buttons, that depending on which is selected will either be deleted or edited from the database. Those are each individual pages using SQL statements (questionedit and questiondelete). However, when i press a button, nothing happens...Any Ideas Here is my javascript <script type="text/javascript"> function SelectedButton(button) { if(button == 'edit') { document.testedit_questionform.action ="testedit_questionedit.php"; } else if(button == 'delete') { document.testedit_questionform.action ="testedit_questiondelete.php"; } document.forms[].testedit_questionform.submit(); } </script> Here is my form (being echoed from a loop) <form name=\"testedit_questionform\" action=\"SelectedButton\" method=\"POST\"> <span class=\"grid_11 prefix_1\" id=\"\" > Question:<input type=\"text\" name=\"QuestionText\" style=\"width:588px; margin-left:10px;\" value=\"$row[0]\"/> <input type=\"button\" value=\"Edit\" name=\"Operation\"onclick=\"submitForm(\'edit\')\" /> <input type=\"button\" value=\"Delete\" name=\"Operation\"onclick=\"submitForm(\'delete\')\" /> <input type=\"hidden\" name=\"QId\" value=\"$row[3]\" /><br />"); </form>

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Need simple Twitter API v1.1 example to show timeline using jQuery or C# ASP.NET

- by Ken Palmer

With Twitter turning off the API 1.0 faucet on 6/11/2013, we have several sites that now fail to display timelines. I've been looking for an "If you did that, now do this" example. Here was Twitter's announcement. https://dev.twitter.com/blog/api-v1-is-retired Here is what we were originally doing to show the Twitter timeline via API 1.0. <div id="twitter"> <ul id="twitter_update_list"></ul> <script type="text/javascript" src="http://twitter.com/javascripts/blogger.js"></script> <script type="text/javascript" src="http://api.twitter.com/1/statuses/user_timeline/companytwitterhandle.json?callback=twitterCallback2&count=1"></script> <div style="float:left;"><a href="https://twitter.com/companytwitterhandle" target="_blank">@companytwitterhandle</a> | </div> <div class="twitterimg"> </div> </div> Initially I tried changing the version in the JavaScript reference URL like so, which did not work. <script type="text/javascript" src="http://api.twitter.com/1.1/statuses/user_timeline/companytwitterhandle.json?callback=twitterCallback2&count=1"></script> Then I looked at the Twitter API documentation (https://dev.twitter.com/docs/api/1.1/overview) which lacks a clear transition example. I don't have 4 or 5 hours to delve into that, or into this disheveled FAQ (https://dev.twitter.com/docs/faq#17750). Then I found this API documentation regarding the user timeline. So I changed the URL again as shown below. https://dev.twitter.com/docs/api/1.1/get/statuses/user_timeline <script type="text/javascript" src="https://api.twitter.com/1.1/statuses/user_timeline.json?screen_name=companytwitterhandle&count=1"></script> That did not work. Using jQuery or C# ASP.NET MVC, how can I transition that interface from Twitter API 1.0 to Twitter API 1.1? My first preference would be for a browser client side implementation if that is possible. Please include a code example. Thanks.

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What is a modern C++ approach to structures containing symbolic constants?

- by Ken

enum bool { FALSE = 0, TRUE = 1 }; I'm wondering how to translate this in a modern C++ approach and if there is a well suited container for that; i know that the enum are not really that appreciated, but i can't think about a real alternative in the C++ world. What if would like to associate the execution of a particular method with a state? Ok, this is the part where i will be more verbose. I would like to stress the fact that i'm asking about structures symbolic constants and not about TRUE and FALSE, i'm not that "needy". Suppose that i have a structure that can represent several states with their own constants enum semaphore { GREEN = 0, ORANGE = 1, RED = 2 }; this is C code, now my question is about how to do the same in C++ if there is a better way. My question continue when i ask about the possibility to do something like an automatic triggering when a change of state will occur, for example: int main{ ... semaphore = 1; ... } and without any extra statements this has to trigger a method() just because the semaphore is now orange. I hope that is more clear now.

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Accessing 'data' argument of with() function?

- by Ken Williams

Is it possible, in the expr expression of the with() function, to access the data argument directly? Here's what I mean conceptually: > print(df) result qid f1 f2 f3 -1 1 0.0000 0.1253 0.0000 -1 1 0.0098 0.0000 0.0000 1 1 0.0000 0.0000 0.1941 -1 2 0.0000 0.2863 0.0948 1 2 0.0000 0.0000 0.0000 1 2 0.0000 0.7282 0.9087 > with(df, subset(.data, select=f1:f3)) # Doesn't work Of course the above example is kind of silly, but it would be handy for things like this: with(subset(df, f2>0), foo(qid, vars=subset(.data, select=f1:f3))) I tried to poke around with environment() and parent.frame() etc., but didn't come up with anything that worked. Maybe this is really a question about eval(), since that's how with.default() is implemented.

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HELP A NEWB (AGAIN) PLZ

- by Ken

Okay, I must be an idiot, because this is my 3rd question for today. Here's my code: date_default_timezone_set("America/Los_Angeles"); include("mainmenu.php"); $con = mysql_connect("localhost", "root", "********"); if(!$con){ die(mysql_error()); } $usrname = $_POST['usrname']; $fname = $_POST['fname']; $lname = $_POST['lname']; $password = $_POST['password']; $email = $_POST['email']; mysql_select_db("`users`, $con) or die(mysql_error()"); $query = ("INSERT INTO `users`.`data` (`id`, `usrname`, `fname`, `lname`, `email`, `password`) VALUES (NULL, '$usrname', '$fname', '$lname', '$email', 'password'))"); mysql_query('$query') or die(mysql_error()); mysql_close($con); echo("Thank you for registering!"); I always get the error returned as: "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '$query' at line 1. Help a newbie. I'm about to stab my monitor.

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Graphical Submit button doesn't 'post' in Firefox or IE

- by Ken

I've looked all over the net to try and solve this problem, but I can't find any solutions. So far, I've checked 3 different browsers. It does not work on IE or FireFox, but it works just fine in Safari. Here's the problem. When I click the button to submit my form, it forwards me to the 'post' URL page - INSTEAD of posting the data, and going to the thank you page like the script commands. Here's the code I'm working with: <form name="loginfrm" method="post" action="http://www.myaffiliatepowersite.com/members/quick_signup.php" style="margin:0; padding:0;"> " /

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Class decorator to declare static member (e.g., for log4net)?

- by Ken

I'm using log4net, and we have a lot of this in our code: public class Foo { private static readonly ILog log = LogManager.GetLogger(typeof(Foo)); .... } One downside is that it means we're pasting this 10-word section all over, and every now and then somebody forgets to change the class name. The log4net FAQ also mentions this alternative possibility, which is even more verbose: public class Foo { private static readonly ILog log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType); ... } Is it possible to write a decorator to define this? I'd really like to say simply: [LogMe] // or perhaps: [LogMe("log")] public class Foo { ... } I've done similar things in other languages, but never a statically-compiled language like C#. Can I define class members from a decorator?

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Introduction to the ASP.NET Web API

- by Stephen.Walther

I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html> Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "\n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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