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  • "Inlining" (kind of) functions at runtime in C

    - by fortran
    Hi, I was thinking about a typical problem that is very JIT-able, but hard to approach with raw C. The scenario is setting up a series of function pointers that are going to be "composed" (as in maths function composition) once at runtime and then called lots and lots of times. Doing it the obvious way involves many virtual calls, that are expensive, and if there are enough nested functions to fill the CPU branch prediction table completely, then the performance with drop considerably. In a language like Lisp, I could probably process the code and substitute the "virtual" call by the actual contents of the functions and then call compile to have an optimized version, but that seems very hacky and error prone to do in C, and using C is a requirement for this problem ;-) So, do you know if there's a standard, portable and safe way to achieve this in C? Cheers

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  • How to define a custom iterator in C++

    - by Robert Martin
    I've seen a number of posts on SO about how to define custom iterators, but nothing that seems to exactly answers my question, which is... How do I create an iterator that hides a nested for loop? For instance, I have a class Foo, inside of the Foo is a Bar, and inside of the Bar is a string. I could write for (const Foo& foo : foo_set) for (const Bar& bar : foo.bar_set) if (bar.my_string != "baz") cout << bar.my_string << endl; but instead I want to be able to do something like: for (const string& good : foo_set) cout << good << endl; How do I do something like this?

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  • Getting data from the next row in Oracle cursor

    - by Chaotic_one
    Hi, I'm building nested tree and I need to get data for the next row in cursor, using Oracle. And I still need current row, so looping forward is not a solution. Example: OPEN emp_cv FOR sql_stmt; LOOP FETCH emp_cv INTO v_rcod,v_rname,v_level; EXIT WHEN emp_cv%NOTFOUND; /*here lies the code for getting v_next_level*/ if v_next_level > v_level then /*code here*/ elsif v_next_level < v_level then /*code here*/ else /*code here*/ end if; END LOOP; CLOSE emp_cv;

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  • Iterating through a range of dates in Python

    - by ShawnMilo
    This is working fine, but I'm looking for any feedback on how to do it better. Right now I think it's better than nested loops, but it starts to get Perl-one-linerish when you have a generator in a list comprehension. Any suggestions are welcome. day_count = (end_date - start_date).days + 1 for single_date in [d for d in (start_date + timedelta(n) for n in range(day_count)) if d <= end_date]: print strftime("%Y-%m-%d", single_date.timetuple()) Notes: I'm not actually using this to print; that's just for demo purposes. The variables start_date and end_date are datetime.date objects, because I don't need the timestamps (they're going to be used to generate a report). I checked the StackOverflow questions which were similar before posting this, but none were exactly the same. Sample Output (for a start date of 2009-05-30 and an end date of 2009-06-09): 2009-05-30 2009-05-31 2009-06-01 2009-06-02 2009-06-03 2009-06-04 2009-06-05 2009-06-06 2009-06-07 2009-06-08 2009-06-09

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  • Erlang bit syntax variable issue

    - by Jimmy Ruska
    Is there any way to format this so it's a valid expression, without adding another step? <<One:8,_:(One*8)>> = <<1,9>>. * 1: illegal bit size These work <<One:8,_:(1*8)>> = <<1,9>>. <<1,9>> <<Eight:8,_:Eight>> = <<8,9>>. <<8,9>> I'm trying to parse a binary with nested data with list comprehensions instead of stacking accumulators.

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  • Two part form in Rails

    - by samuel02
    I have some two nested resources, so that a Product can have many Bookings. On one page in a different controller I want to create a new booking and since it's a "general" booking I want a select menu to appear in a modal window where the user is able to pick one of the existing products and then go to the booking page. How can I do this? I have no problem setting up the modal and the "New booking" page is already there. What I need is a form that generates a list of existing products, picks the selected product id and then gets /products/:product_id/bookings/new . Any help appreciated! I realize my title does not describe my problem very good so better suggestions are highly welcome!

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  • Twin edges - Half edge data structure

    - by Pradeep Kumar
    I have implemented a Half-edge data structure for loading 3d objects. I find that the part of assigning twin/pair edges takes the longest computation time (especially for objects which have hundreds of thousands half edges). The reason is that I use nested loops to accomplish this. Is there a simpler and efficient way of doing this? Below is the code which I've written. HE is the half-edge data structure. hearr is a vector containing all the half edges. vert is the starting vertex and end is the ending vertex. Thanks!! HE *e1,*e2; for(size_t i=0;i<hearr.size();i++){ e1=hearr[i]; for(size_t j=1;j<hearr.size();j++){ e2=hearr[j]; if((e1->vert==e2->end)&&(e2->vert==e1->end)){ e1->twin=e2; e2->twin=e1; } } }

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  • A 3-D grid of regularly spaced points

    - by Jack
    I want to create a list containing the 3-D coords of a grid of regularly spaced points, each as a 3-element tuple. I'm looking for advice on the most efficient way to do this. In C++ for instance, I simply loop over three nested loops, one for each coordinate. In Matlab, I would probably use the meshgrid function (which would do it in one command). I've read about meshgrid and mgrid in Python, and I've also read that using numpy's broadcasting rules is more efficient. It seems to me that using the zip function in combination with the numpy broadcast rules might be the most efficient way, but zip doesn't seem to be overloaded in numpy.

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  • Creating a file/folder structure and zipping it up?

    - by makeee
    I have a directory of image files and I need a php script or shell script that will rename them, create a structure of nested directories, and then insert each image into a specified place in the directory hierarchy. Ideally I would just specify a parent directory for each file and a parent directory for each directory and it would build it. And then finally, I need the script to zip up the whole thing. There's probably not an existing php class that will do all this for me, but if anyone knows of a php class or other script available online that would handle a lot of this logic that would be great.

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  • AS3: How to get all XML-Nodes with a special attribute? (With sourch)

    - by insnet
    Hi there The Challenge: i d like to collect all nodes with the attribute "id". The Problem: The code doenst work with nested nodes. <?xml version="1.0" encoding="utf-8"?><contentmap><fonts id="fonts"> fonts/Arial.swf swf/library_main.swf private function onXMLLoader(event : Event) : void { _xml = _loader.getXML(event.target.url.url); var searchTerms : XMLList = _xml.*.(hasOwnProperty('@id')); if (searchTerms.length() 0 ) { _NodeArray = new Array(); _parseNode(searchTerms); } private function _parseNode(xml : XMLList) : void { for each (var node: XML in xml) { if(!node.hasSimpleContent()) { _parseNode(node.children()); } else { var nodeObject : Object = new Object(); nodeObject['value'] = node.text(); for each(var a:XML in node.@*) { var name : String = String(a.name()); nodeObject[name] = a.toXMLString(); } _NodeArray.push(nodeObject); } } }

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  • google calendar api (java) authentication error in dynamic web project

    - by HazProblem
    org.springframework.web.util.NestedServletException: Handler processing failed; nested exception is java.lang.NoClassDefFoundError: com/google/gdata/util/AuthenticationException org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:823) org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) javax.servlet.http.HttpServlet.service(HttpServlet.java:641) javax.servlet.http.HttpServlet.service(HttpServlet.java:722) org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88) org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) The class i have written works fine as a normal java application, but when i try to use the code in an dynamic web project i get this authentication failure. Where´s the difference?

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  • MySQL is there a Single Select to Query Various Unrelated Values from a database?

    - by zzapper
    I saw somewhere what seemed to be nested selects, one "master" select on the "outside" and a series of selects inside- is this possible? I'm not talking about joins as there is particular relation between the selects. I seem not to be explaining myself very well. I want to do a single query which will pull out a series of stats from various tables latest order, latest customer, largest order. Obviously I can do that with a series of selects. The example I saw was something like select ( select ... from tbl_1 where .., select ... from tbl_2 where .., select ... from tbl_3 where .., ... )

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  • Rails - How to secure foreign keys and still allow association selection

    - by Bryce
    For simplicity, assume that I have a simple has-many-through relationship class User < ActiveRecord::Base has_many :courses, :through => :registrations end class Registration < ActiveRecord::Base belongs_to :user belongs_to :course end class Course < ActiveRecord::Base has_many :users, :through => :registrations end I want to keep my app secure, so I use attr_accessible to whitelist my attributes. My question is twofold: How would I set up my whitelist attributes such that I could create a new Registration object through a form (passing in :user and :course, but not risk allowing those foreign keys to be maliciously updated later? How would I set up my validations such that both belongs_to associations are required BUT also allow for Registration objects to be created in nested forms?

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  • scala: how to rewrite this function using for comprehension

    - by opensas
    I have this piece of code with a couple of nasty nested checks... I'm pretty sure it can be rewritten with a nice for comprehension, but I'm a bit confused about how to mix the pattern matching stuff // first tries to find the token in a header: "authorization: ideas_token=xxxxx" // then tries to find the token in the querystring: "ideas_token=xxxxx" private def applicationTokenFromRequest(request: Request[AnyContent]): Option[String] = { val fromHeaders: Option[String] = request.headers.get("authorization") val tokenRegExp = """^\s*ideas_token\s*=\s*(\w+)\s*$""".r val tokenFromHeader: Option[String] = { if (fromHeaders.isDefined) { val header = fromHeaders.get if (tokenRegExp.pattern.matcher(header).matches) { val tokenRegExp(extracted) = header Some(extracted) } else { None } } else { None } } // try to find it in the queryString tokenFromHeader.orElse { request.queryString.get("ideas_token") } } any hint you can give me?

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  • Mapping C structure to an XML element

    - by EFraim
    Suppose I have a structure in C or C++, such as: struct ConfigurableElement { int ID; char* strName; long prop1; long prop2; ... }; I would like to load/save it to/from the following XML element: <ConfigurableElement ID="1" strName="namedElem" prop1="2" prop2="3" ... /> Such a mapping can be trivially done in Java/C# or any other language with run-time reflection for the matter. Can it be done in any non-tedious way in C++ with macros/template trickery? Bonus points for handling nested structures/unions.

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  • SQL to get rows (not groups) that match an aggregate

    - by xulochavez
    Given table USER (name, city, age), what's the best way to get the user details of oldest user per city? I have seen the following example SQL used in Oracle which I think it works select name, city, age from USER, (select city as maxCity, max(age) as maxAge from USER group by city) where city=maxCity and age=maxAge So in essence: use a nested query to select the grouping key and aggregate for it, then use it as another table in the main query and join with the grouping key and the aggregate value for each key. Is this the standard SQL way of doing it? Is it any quicker than using a temporary table, or is in fact using a temporary table interanlly anyway?

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  • Praw (Redditt API) How to retrieve replies to a comment past 10 levels deep

    - by jpreed00
    Ok, so I've written some code that, for all intents and purposes, should work: def checkComments(comments): for comment in comments: print comment.body checkComments(comment.replies) def processSub(sub): sub.replace_more_comments(limit=None, threshold=0) checkComments(sub.comments) #login and subreddit init stuff here subs = mysubreddit.get_hot(limit=50) for sub in subs: processSub(sub) However, given a submission that has 50 nested replies like so: root comment -> 1st reply -> 2nd reply -> 3rd reply ... -> 50th reply The above code only prints: root comment 1st reply 2nd reply 3rd reply 4th reply 5th reply 6th reply 7th reply 8th reply 9th reply Any idea how I can get the remaining 41 levels of replies? Or is this a praw limitation?

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  • Visual Basic Display Square

    - by user1724157
    Alright I'm currently lost on a particular assignment I have for a class. I've seen many examples of this app but none of them see to help my problem is as follows: Write a Sub procedure "DisplaySquare" to display the solid square. The size should be specified by the integer parameter "size". The character that fills the square should be specified by the string parameter "fillCharacter. Use a For...Next statement nested within another For...Next statement to create the square. The outer For...Next specifies what row is currently being displayed. The inner For...Next appends all the characters that form the row to a display string. So it should come out like as follows: if a user enters "8" and "#" ######## ######## ######## ######## ######## ######## ######## ######## Any help would be appreciated.

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  • list within a list

    - by atm atm
    I'm working on this problem, but I cannot figure out the second part. I tried using reverse list but it did not work out how I planned it. Given a list L (e.g. [1,2,3,4]), write a program that generates the following nested lists: L1 = [[1],[1,2],[1,2,3],[1,2,3,4]], L2 = [[4],[3,4],[2,3,4],[1,2,3,4]]. My code that I have so far: mylist=[,1,2,3,4] print("Orginal list L=",mylist) n=len(mylist) l1=[] l2=[] for x in range(1,n+1,1): l1.append(mylist[0:x]) print("L1=",l1) #prints final product of l1 mylist.reverse() #this is where i get messed up for x in range(1,n+1,1): l2.append(mylist[0:x]) print("L2=",l2)

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  • Difference between local and instance variables in ruby

    - by fflyer05
    I am working on a script that creates several fairly complex nested hash datastructures and then iterates through them conditionally creating database records. This is a standalone script using active record. After several minutes of running I noticed a significant lag in server responsiveness and discovered that the script, while being set to be nice +19, was enjoying a steady %85 - %90 total server memory. In this case I am using instance variables simply for readability. It helps knowing what is going to be re-used outside of the loop vs. what won't. Is there a reason to not use instance variables when they are not needed? Are there differences in memory allocation and management between local and instance variables? Would it help setting @variable = nil when its no longer needed?

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  • What are some Coldfusion (mx7 and greater) "Gotchas" that I should know about?

    - by jakeonrails
    I just spent half the day troubleshooting what is apparently a rather famous gotcha for Coldfusion MX7 and below: The nested query loop bug: Where you are required to reference the current_row of the outer query or else you will only see the first record. For example: <cfloop query="outer"> <cfloop query="innner"> <p>#outer.field#</p><!--- this won't work, you'll only get the first row ---> <p>#outer.field[current_row]#</p><!--- you must do this instead ---> </cfloop> </cfloop> Are there any other ways in which ColdFusion does not work in the obvious way?

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  • How do submit an object to a struts2 action using jQuery?

    - by James Drinkard
    I have an object that I'm populating from a selection off a table row that a user selects. I have a jQuery function that captures the click event and a hidden form field populates an id I need. However, I'm not sure as to the proper way to send off that object to a struts2 action? I tried using this: $(function() { $('#tbl tr').click(function() { var id = $(this).closest('tr').find('input:hidden').val(); var page = "<s:url action='update/deleteInfo.action'/>?model.isDelete=true&model.info.id=id"; console.log(page); window.location.href=(page); }); }); The model object has an isDelete boolean variable and the model has a nested info object that has an id variable with getter/setters. However, when I send this across, the model object isn't populated with these entries. Is there a way to do this or a better way than the url tag?

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  • Nesting if else statements in PHP to validate a URL

    - by John
    I'm currently writing up a function in order to validate a URL by exploding it into different parts and matching those parts with strings I've defined. This is the function I'm using so far: function validTnet($tnet_url) { $tnet_2 = "defined2"; $tnet_3 = "defined3"; $tnet_5 = "defined5"; $tnet_7 = ""; if($exp_url[2] == $tnet_2) { #show true, proceed to next validation if($exp_url[3] == $tnet_3) { #true, and next if($exp_url[5] == $tnet_5) { #true, and last if($exp_url[7] == $tnet_7) { #true, valid } } } } else { echo "failed on tnet_2"; } } For some reason I'm unable to think of the way to code (or search for the proper term) of how to break out of the if statements that are nested. What I would like to do check each part of the URL, starting with $tnet_2, and if it fails one of the checks ($tnet_2, $tnet_3, $tnet_5 or $tnet_7), output that it fails, and break out of the if statement. Is there an easy way to accomplish this using some of the code I have already?

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  • jqGrid - dynamically load different drop down values for different rows depending on another column value

    - by Renso
    Goal: As we all know the jqGrid examples in the demo and the Wiki always refer to static values for drop down boxes. This of course is a personal preference but in dynamic design these values should be populated from the database/xml file, etc, ideally JSON formatted. Can you do this in jqGrid, yes, but with some custom coding which we will briefly show below (refer to some of my other blog entries for a more detailed discussion on this topic). What you CANNOT do in jqGrid, referrign here up and to version 3.8.x, is to load different drop down values for different rows in the jqGrid. Well, not without some trickery, which is what this discussion is about. Issue: Of course the issue is that jqGrid has been designed for high performance and thus I have no issue with them loading a  reference to a single drop down values list for every column. This way if you have 500 rows or one, each row only refers to a single list for that particuolar column. Nice! SO how easy would it be to simply traverse the grid once loaded on gridComplete or loadComplete and simply load the select tag's options from scratch, via ajax, from memory variable, hard coded etc? Impossible! Since their is no embedded SELECT tag within each cell containing the drop down values (remeber it only has a reference to that list in memory), all you will see when you inspect the cell prior to clicking on it, or even before and on beforeEditCell, is an empty <TD></TD>. When trying to load that list via a click event on that cell will temporarily load the list but jqGrid's last internal callback event will remove it and replace it with the old one, and you are back to square one. Solution: Yes, after spending a few hours on this found a solution to the problem that does not require any updates to jqGrid source code, thank GOD! Before we get into the coding details, the solution here can of course be customized to suite your specific needs, this one loads the entire drop down list that would be needed across all rows once into global variable. I then parse this object that contains all the properties I need to filter the rows depending on which ones I want the user to see based off of another cell value in that row. This only happens when clicking the cell, so no performance penalty. You may of course to load it via ajax when the user clicks the cell, but I found it more effecient to load the entire list as part of jqGrid's normal editoptions: { multiple: false, value: listingStatus } colModel options which again keeps only a reference to the sinlge list, no duplciation. Lets get into the meat and potatoes of it.         var acctId = $('#Id').val();         var data = $.ajax({ url: $('#ajaxGetAllMaterialsTrackingLookupDataUrl').val(), data: { accountId: acctId }, dataType: 'json', async: false, success: function(data, result) { if (!result) alert('Failure to retrieve the Alert related lookup data.'); } }).responseText;         var lookupData = eval('(' + data + ')');         var listingCategory = lookupData.ListingCategory;         var listingStatus = lookupData.ListingStatus;         var catList = '{';         $(lookupData.ListingCategory).each(function() {             catList += this.Id + ':"' + this.Name + '",';         });         catList += '}';         var lastsel;         var ignoreAlert = true;         $(item)         .jqGrid({             url: listURL,             postData: '',             datatype: "local",             colNames: ['Id', 'Name', 'Commission<br />Rep', 'Business<br />Group', 'Order<br />Date', 'Edit', 'TBD', 'Month', 'Year', 'Week', 'Product', 'Product<br />Type', 'Online/<br />Magazine', 'Materials', 'Special<br />Placement', 'Logo', 'Image', 'Text', 'Contact<br />Info', 'Everthing<br />In', 'Category', 'Status'],             colModel: [                 { name: 'Id', index: 'Id', hidden: true, hidedlg: true },                 { name: 'AccountName', index: 'AccountName', align: "left", resizable: true, search: true, width: 100 },                 { name: 'OnlineName', index: 'OnlineName', align: 'left', sortable: false, width: 80 },                 { name: 'ListingCategoryName', index: 'ListingCategoryName', width: 85, editable: true, hidden: false, edittype: "select", editoptions: { multiple: false, value: eval('(' + catList + ')') }, editrules: { required: false }, formatoptions: { disabled: false} }             ],             jsonReader: {                 root: "List",                 page: "CurrentPage",                 total: "TotalPages",                 records: "TotalRecords",                 userdata: "Errors",                 repeatitems: false,                 id: "0"             },             rowNum: $rows,             rowList: [10, 20, 50, 200, 500, 1000, 2000],             imgpath: jQueryImageRoot,             pager: $(item + 'Pager'),             shrinkToFit: true,             width: 1455,             recordtext: 'Traffic lines',             sortname: 'OrderDate',             viewrecords: true,             sortorder: "asc",             altRows: true,             cellEdit: true,             cellsubmit: "remote",             cellurl: editURL + '?rows=' + $rows + '&page=1',             loadComplete: function() {               },             gridComplete: function() {             },             loadError: function(xhr, st, err) {             },             afterEditCell: function(rowid, cellname, value, iRow, iCol) {                 var select = $(item).find('td.edit-cell select');                 $(item).find('td.edit-cell select option').each(function() {                     var option = $(this);                     var optionId = $(this).val();                     $(lookupData.ListingCategory).each(function() {                         if (this.Id == optionId) {                                                       if (this.OnlineName != $(item).getCell(rowid, 'OnlineName')) {                                 option.remove();                                 return false;                             }                         }                     });                 });             },             search: true,             searchdata: {},             caption: "List of all Traffic lines",             editurl: editURL + '?rows=' + $rows + '&page=1',             hiddengrid: hideGrid   Here is the JSON data returned via the ajax call during the jqGrid function call above (NOTE it must be { async: false}: {"ListingCategory":[{"Id":29,"Name":"Document Imaging & Management","OnlineName":"RF Globalnet"} ,{"Id":1,"Name":"Ancillary Department Hardware","OnlineName":"Healthcare Technology Online"} ,{"Id":2,"Name":"Asset Tracking","OnlineName":"Healthcare Technology Online"} ,{"Id":3,"Name":"Asset Tracking","OnlineName":"Healthcare Technology Online"} ,{"Id":4,"Name":"Asset Tracking","OnlineName":"Healthcare Technology Online"} ,{"Id":5,"Name":"Document Imaging & Management","OnlineName":"Healthcare Technology Online"} ,{"Id":6,"Name":"Document Imaging & Management","OnlineName":"Healthcare Technology Online"} ,{"Id":7,"Name":"EMR/EHR Software","OnlineName":"Healthcare Technology Online"}]} I only need the Id and Name for the drop down list, but the third column in the JSON object is important, it is the only that I match up with the OnlineName in the jqGrid column, and then in the loop during afterEditCell simply remove the ones I don't want the user to see. That's it!

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  • Rendering ASP.NET MVC Views to String

    - by Rick Strahl
    It's not uncommon in my applications that I require longish text output that does not have to be rendered into the HTTP output stream. The most common scenario I have for 'template driven' non-Web text is for emails of all sorts. Logon confirmations and verifications, email confirmations for things like orders, status updates or scheduler notifications - all of which require merged text output both within and sometimes outside of Web applications. On other occasions I also need to capture the output from certain views for logging purposes. Rather than creating text output in code, it's much nicer to use the rendering mechanism that ASP.NET MVC already provides by way of it's ViewEngines - using Razor or WebForms views - to render output to a string. This is nice because it uses the same familiar rendering mechanism that I already use for my HTTP output and it also solves the problem of where to store the templates for rendering this content in nothing more than perhaps a separate view folder. The good news is that ASP.NET MVC's rendering engine is much more modular than the full ASP.NET runtime engine which was a real pain in the butt to coerce into rendering output to string. With MVC the rendering engine has been separated out from core ASP.NET runtime, so it's actually a lot easier to get View output into a string. Getting View Output from within an MVC Application If you need to generate string output from an MVC and pass some model data to it, the process to capture this output is fairly straight forward and involves only a handful of lines of code. The catch is that this particular approach requires that you have an active ControllerContext that can be passed to the view. This means that the following approach is limited to access from within Controller methods. Here's a class that wraps the process and provides both instance and static methods to handle the rendering:/// <summary> /// Class that renders MVC views to a string using the /// standard MVC View Engine to render the view. /// /// Note: This class can only be used within MVC /// applications that have an active ControllerContext. /// </summary> public class ViewRenderer { /// <summary> /// Required Controller Context /// </summary> protected ControllerContext Context { get; set; } public ViewRenderer(ControllerContext controllerContext) { Context = controllerContext; } /// <summary> /// Renders a full MVC view to a string. Will render with the full MVC /// View engine including running _ViewStart and merging into _Layout /// </summary> /// <param name="viewPath"> /// The path to the view to render. Either in same controller, shared by /// name or as fully qualified ~/ path including extension /// </param> /// <param name="model">The model to render the view with</param> /// <returns>String of the rendered view or null on error</returns> public string RenderView(string viewPath, object model) { return RenderViewToStringInternal(viewPath, model, false); } /// <summary> /// Renders a partial MVC view to string. Use this method to render /// a partial view that doesn't merge with _Layout and doesn't fire /// _ViewStart. /// </summary> /// <param name="viewPath"> /// The path to the view to render. Either in same controller, shared by /// name or as fully qualified ~/ path including extension /// </param> /// <param name="model">The model to pass to the viewRenderer</param> /// <returns>String of the rendered view or null on error</returns> public string RenderPartialView(string viewPath, object model) { return RenderViewToStringInternal(viewPath, model, true); } public static string RenderView(string viewPath, object model, ControllerContext controllerContext) { ViewRenderer renderer = new ViewRenderer(controllerContext); return renderer.RenderView(viewPath, model); } public static string RenderPartialView(string viewPath, object model, ControllerContext controllerContext) { ViewRenderer renderer = new ViewRenderer(controllerContext); return renderer.RenderPartialView(viewPath, model); } protected string RenderViewToStringInternal(string viewPath, object model, bool partial = false) { // first find the ViewEngine for this view ViewEngineResult viewEngineResult = null; if (partial) viewEngineResult = ViewEngines.Engines.FindPartialView(Context, viewPath); else viewEngineResult = ViewEngines.Engines.FindView(Context, viewPath, null); if (viewEngineResult == null) throw new FileNotFoundException(Properties.Resources.ViewCouldNotBeFound); // get the view and attach the model to view data var view = viewEngineResult.View; Context.Controller.ViewData.Model = model; string result = null; using (var sw = new StringWriter()) { var ctx = new ViewContext(Context, view, Context.Controller.ViewData, Context.Controller.TempData, sw); view.Render(ctx, sw); result = sw.ToString(); } return result; } } The key is the RenderViewToStringInternal method. The method first tries to find the view to render based on its path which can either be in the current controller's view path or the shared view path using its simple name (PasswordRecovery) or alternately by its full virtual path (~/Views/Templates/PasswordRecovery.cshtml). This code should work both for Razor and WebForms views although I've only tried it with Razor Views. Note that WebForms Views might actually be better for plain text as Razor adds all sorts of white space into its output when there are code blocks in the template. The Web Forms engine provides more accurate rendering for raw text scenarios. Once a view engine is found the view to render can be retrieved. Views in MVC render based on data that comes off the controller like the ViewData which contains the model along with the actual ViewData and ViewBag. From the View and some of the Context data a ViewContext is created which is then used to render the view with. The View picks up the Model and other data from the ViewContext internally and processes the View the same it would be processed if it were to send its output into the HTTP output stream. The difference is that we can override the ViewContext's output stream which we provide and capture into a StringWriter(). After rendering completes the result holds the output string. If an error occurs the error behavior is similar what you see with regular MVC errors - you get a full yellow screen of death including the view error information with the line of error highlighted. It's your responsibility to handle the error - or let it bubble up to your regular Controller Error filter if you have one. To use the simple class you only need a single line of code if you call the static methods. Here's an example of some Controller code that is used to send a user notification to a customer via email in one of my applications:[HttpPost] public ActionResult ContactSeller(ContactSellerViewModel model) { InitializeViewModel(model); var entryBus = new busEntry(); var entry = entryBus.LoadByDisplayId(model.EntryId); if ( string.IsNullOrEmpty(model.Email) ) entryBus.ValidationErrors.Add("Email address can't be empty.","Email"); if ( string.IsNullOrEmpty(model.Message)) entryBus.ValidationErrors.Add("Message can't be empty.","Message"); model.EntryId = entry.DisplayId; model.EntryTitle = entry.Title; if (entryBus.ValidationErrors.Count > 0) { ErrorDisplay.AddMessages(entryBus.ValidationErrors); ErrorDisplay.ShowError("Please correct the following:"); } else { string message = ViewRenderer.RenderView("~/views/template/ContactSellerEmail.cshtml",model, ControllerContext); string title = entry.Title + " (" + entry.DisplayId + ") - " + App.Configuration.ApplicationName; AppUtils.SendEmail(title, message, model.Email, entry.User.Email, false, false)) } return View(model); } Simple! The view in this case is just a plain MVC view and in this case it's a very simple plain text email message (edited for brevity here) that is created and sent off:@model ContactSellerViewModel @{ Layout = null; }re: @Model.EntryTitle @Model.ListingUrl @Model.Message ** SECURITY ADVISORY - AVOID SCAMS ** Avoid: wiring money, cross-border deals, work-at-home ** Beware: cashier checks, money orders, escrow, shipping ** More Info: @(App.Configuration.ApplicationBaseUrl)scams.html Obviously this is a very simple view (I edited out more from this page to keep it brief) -  but other template views are much more complex HTML documents or long messages that are occasionally updated and they are a perfect fit for Razor rendering. It even works with nested partial views and _layout pages. Partial Rendering Notice that I'm rendering a full View here. In the view I explicitly set the Layout=null to avoid pulling in _layout.cshtml for this view. This can also be controlled externally by calling the RenderPartial method instead: string message = ViewRenderer.RenderPartialView("~/views/template/ContactSellerEmail.cshtml",model, ControllerContext); with this line of code no layout page (or _viewstart) will be loaded, so the output generated is just what's in the view. I find myself using Partials most of the time when rendering templates, since the target of templates usually tend to be emails or other HTML fragment like output, so the RenderPartialView() method is definitely useful to me. Rendering without a ControllerContext The preceding class is great when you're need template rendering from within MVC controller actions or anywhere where you have access to the request Controller. But if you don't have a controller context handy - maybe inside a utility function that is static, a non-Web application, or an operation that runs asynchronously in ASP.NET - which makes using the above code impossible. I haven't found a way to manually create a Controller context to provide the ViewContext() what it needs from outside of the MVC infrastructure. However, there are ways to accomplish this,  but they are a bit more complex. It's possible to host the RazorEngine on your own, which side steps all of the MVC framework and HTTP and just deals with the raw rendering engine. I wrote about this process in Hosting the Razor Engine in Non-Web Applications a long while back. It's quite a process to create a custom Razor engine and runtime, but it allows for all sorts of flexibility. There's also a RazorEngine CodePlex project that does something similar. I've been meaning to check out the latter but haven't gotten around to it since I have my own code to do this. The trick to hosting the RazorEngine to have it behave properly inside of an ASP.NET application and properly cache content so templates aren't constantly rebuild and reparsed. Anyway, in the same app as above I have one scenario where no ControllerContext is available: I have a background scheduler running inside of the app that fires on timed intervals. This process could be external but because it's lightweight we decided to fire it right inside of the ASP.NET app on a separate thread. In my app the code that renders these templates does something like this:var model = new SearchNotificationViewModel() { Entries = entries, Notification = notification, User = user }; // TODO: Need logging for errors sending string razorError = null; var result = AppUtils.RenderRazorTemplate("~/views/template/SearchNotificationTemplate.cshtml", model, razorError); which references a couple of helper functions that set up my RazorFolderHostContainer class:public static string RenderRazorTemplate(string virtualPath, object model,string errorMessage = null) { var razor = AppUtils.CreateRazorHost(); var path = virtualPath.Replace("~/", "").Replace("~", "").Replace("/", "\\"); var merged = razor.RenderTemplateToString(path, model); if (merged == null) errorMessage = razor.ErrorMessage; return merged; } /// <summary> /// Creates a RazorStringHostContainer and starts it /// Call .Stop() when you're done with it. /// /// This is a static instance /// </summary> /// <param name="virtualPath"></param> /// <param name="binBasePath"></param> /// <param name="forceLoad"></param> /// <returns></returns> public static RazorFolderHostContainer CreateRazorHost(string binBasePath = null, bool forceLoad = false) { if (binBasePath == null) { if (HttpContext.Current != null) binBasePath = HttpContext.Current.Server.MapPath("~/"); else binBasePath = AppDomain.CurrentDomain.BaseDirectory; } if (_RazorHost == null || forceLoad) { if (!binBasePath.EndsWith("\\")) binBasePath += "\\"; //var razor = new RazorStringHostContainer(); var razor = new RazorFolderHostContainer(); razor.TemplatePath = binBasePath; binBasePath += "bin\\"; razor.BaseBinaryFolder = binBasePath; razor.UseAppDomain = false; razor.ReferencedAssemblies.Add(binBasePath + "ClassifiedsBusiness.dll"); razor.ReferencedAssemblies.Add(binBasePath + "ClassifiedsWeb.dll"); razor.ReferencedAssemblies.Add(binBasePath + "Westwind.Utilities.dll"); razor.ReferencedAssemblies.Add(binBasePath + "Westwind.Web.dll"); razor.ReferencedAssemblies.Add(binBasePath + "Westwind.Web.Mvc.dll"); razor.ReferencedAssemblies.Add("System.Web.dll"); razor.ReferencedNamespaces.Add("System.Web"); razor.ReferencedNamespaces.Add("ClassifiedsBusiness"); razor.ReferencedNamespaces.Add("ClassifiedsWeb"); razor.ReferencedNamespaces.Add("Westwind.Web"); razor.ReferencedNamespaces.Add("Westwind.Utilities"); _RazorHost = razor; _RazorHost.Start(); //_RazorHost.Engine.Configuration.CompileToMemory = false; } return _RazorHost; } The RazorFolderHostContainer essentially is a full runtime that mimics a folder structure like a typical Web app does including caching semantics and compiling code only if code changes on disk. It maps a folder hierarchy to views using the ~/ path syntax. The host is then configured to add assemblies and namespaces. Unfortunately the engine is not exactly like MVC's Razor - the expression expansion and code execution are the same, but some of the support methods like sections, helpers etc. are not all there so templates have to be a bit simpler. There are other folder hosts provided as well to directly execute templates from strings (using RazorStringHostContainer). The following is an example of an HTML email template @inherits RazorHosting.RazorTemplateFolderHost <ClassifiedsWeb.SearchNotificationViewModel> <html> <head> <title>Search Notifications</title> <style> body { margin: 5px;font-family: Verdana, Arial; font-size: 10pt;} h3 { color: SteelBlue; } .entry-item { border-bottom: 1px solid grey; padding: 8px; margin-bottom: 5px; } </style> </head> <body> Hello @Model.User.Name,<br /> <p>Below are your Search Results for the search phrase:</p> <h3>@Model.Notification.SearchPhrase</h3> <small>since @TimeUtils.ShortDateString(Model.Notification.LastSearch)</small> <hr /> You can see that the syntax is a little different. Instead of the familiar @model header the raw Razor  @inherits tag is used to specify the template base class (which you can extend). I took a quick look through the feature set of RazorEngine on CodePlex (now Github I guess) and the template implementation they use is closer to MVC's razor but there are other differences. In the end don't expect exact behavior like MVC templates if you use an external Razor rendering engine. This is not what I would consider an ideal solution, but it works well enough for this project. My biggest concern is the overhead of hosting a second razor engine in a Web app and the fact that here the differences in template rendering between 'real' MVC Razor views and another RazorEngine really are noticeable. You win some, you lose some It's extremely nice to see that if you have a ControllerContext handy (which probably addresses 99% of Web app scenarios) rendering a view to string using the native MVC Razor engine is pretty simple. Kudos on making that happen - as it solves a problem I see in just about every Web application I work on. But it is a bummer that a ControllerContext is required to make this simple code work. It'd be really sweet if there was a way to render views without being so closely coupled to the ASP.NET or MVC infrastructure that requires a ControllerContext. Alternately it'd be nice to have a way for an MVC based application to create a minimal ControllerContext from scratch - maybe somebody's been down that path. I tried for a few hours to come up with a way to make that work but gave up in the soup of nested contexts (MVC/Controller/View/Http). I suspect going down this path would be similar to hosting the ASP.NET runtime requiring a WorkerRequest. Brrr…. The sad part is that it seems to me that a View should really not require much 'context' of any kind to render output to string. Yes there are a few things that clearly are required like paths to the virtual and possibly the disk paths to the root of the app, but beyond that view rendering should not require much. But, no such luck. For now custom RazorHosting seems to be the only way to make Razor rendering go outside of the MVC context… Resources Full ViewRenderer.cs source code from Westwind.Web.Mvc library Hosting the Razor Engine for Non-Web Applications RazorEngine on GitHub© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET   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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