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  • excel automation edit existing chart

    - by user330737
    Hi Everyone, I need excel automation expert here. I have chart with x-axis contains label: Jan,Feb,Mar,Apr and y-axis contains label: 10,20,30,40. Chart type is Bar. Can anyone show me a csharp code how to change to Bar color to different color if the month is Mar? I hope you guy understand my question since I can't put the image on stackoverflow. thank you

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  • Does a simple delphi form app needs any libraries or dependencies to deploy?

    - by peterg
    I need to code a simple form application and I want to make it easy to deploy (without installing libraries or dependencies), I don't want to use visual studio cpp or csharp because clr apps compile with .net frameworks and I have no much experience with mfc and dialogs. So I was wondering which libraries does a simple delphi vcl forms app (those using TForm) use, because I've never had to install anything to run simple delphi apps.

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  • Create thumbnail and reduce image size

    - by oo
    I have very large images (jpg) and i want to write a csharp program to loop through the files and reduce the size of each image by 75%. I tried this: Image thumbNail = image.GetThumbnailImage(800, 600, null, new IntPtr()); but the file size is still very large. Is there anyway to create thumbnails and have the filesize be much smaller?

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  • Override generic methods in c#

    - by Pascal
    I thought I can not override generic methods of a derived class. http://my.safaribooksonline.com/book/programming/csharp/9780071741163/generics/ch18lev1sec13 The code in this link runs fine. The overriden method is called although the instance type of the base class is used and not the instance of the derived type. Now I am confused because a former question of mine Type parameter declaration must be identifier not a type is about calling the overriding generic method with the instance of base type which did NOT work!

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  • Reading Excel by OLEDB reads strings as DBNull

    - by Sathish
    I am reading Excel file using OLEDB in Csharp i have shown the sample excel data what i have F1 F2 F3 F4 India 23 44 4 China 4 8 Month 6 USA 45 Neg 4 When i read this data and check in my DataTable i get Null values for "Month 6" and "Neg" where as i can be able get the F1 column correctly... my connection string is as shown Provider=Microsoft.ACE.OLEDB.12.0;Data Source=[XLSource];Extended Properties=Excel 12.0;

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  • The Definitive C++ Book Guide and List

    - by grepsedawk
    After more than a few questions about deciding on C++ books I thought we could make a better community wiki version. Providing QUALITY books and an approximate skill level. Maybe we can add a short blurb/description about each book that you have personally read / benefited from. Feel free to debate quality, headings, etc. Note: There is a similar post for C: The Definitive C Book Guide and List Reference Style - All Levels The C++ Programming Language - Bjarne Stroustrup C++ Standard Library Tutorial and Reference - Nicolai Josuttis Beginner Introductory: C++ Primer - Stanley Lippman / Josée Lajoie / Barbara E. Moo Accelerated C++ - Andrew Koenig / Barbara Moo Thinking in C++ - Bruce Eckel (2 volumes, 2nd is more about standard library, but still very good) Best practices: Effective C++ - Scott Meyers Effective STL - Scott Meyers Intermediate More Effective C++ - Scott Meyers Exceptional C++ - Herb Sutter More Exceptional C++ - Herb Sutter C++ Coding Standards: 101 Rules, Guidelines, and Best Practices - Herb Sutter / Andrei Alexandrescu C++ Templates The Complete Guide - David Vandevoorde / Nicolai M. Josuttis Large Scale C++ Software Design - John Lakos Above Intermediate Modern C++ Design - Andrei Alexandrescu C++ Template Metaprogramming - David Abrahams and Aleksey Gurtovoy Inside the C++ Object Model - Stanley Lippman Classics / Older Note: Some information contained within these books may not be up to date and no longer considered best practice. The Design and Evolution of C++ - Bjarne Stroustrup Ruminations on C++ Andrew Koenig / Barbara Moo Advanced C++ Programming Styles and Idioms - James Coplien

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  • Using EigenObjectRecognizer

    - by Meko
    Hi. I am trying make Facial recognition using Emgu Cv. And using EigenObjectRecognizer could I do it? Also is some one can explain that usage of it? because if there is a no same foto it also returns value. Here is example from Internet Image<Gray, Byte>[] trainingImages = new Image<Gray,Byte>[5]; trainingImages[0] = new Image<Gray, byte>("brad.jpg"); trainingImages[1] = new Image<Gray, byte>("david.jpg"); trainingImages[2] = new Image<Gray, byte>("foof.jpg"); trainingImages[3] = new Image<Gray, byte>("irfan.jpg"); trainingImages[4] = new Image<Gray, byte>("joel.jpg"); String[] labels = new String[] { "Brad", "David", "Foof", "Irfan" , "Joel"} MCvTermCriteria termCrit = new MCvTermCriteria(16, 0.001); EigenObjectRecognizer recognizer = new EigenObjectRecognizer( trainingImages, labels, 5000, ref termCrit); Image<Gray,Byte> testImage = new Image<Gray,Byte>("brad_test.jpg"); String label = recognizer.Recognize(testImage); Console.Write(label); It returns brad .But if I change photo in testimage it also retunrs some name or even Brad.Is it good for face recognition to use this method?Or is there any better method?

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  • Selenium IDE - Passing a URL string variable into a conditional 'gotoIf' statement throws a Syntax e

    - by user318568
    I am trying to store the current url (http://example.com)in a variable and compare it with another string as a condition in the gotoIf command (part of the gotoIf extension.js): storeLocation || url gotoIf || ${url}=="http://example.com" || label When I run this seleniun ide throws this error: [error] Unexpected Exception: message -> syntax error, fileName -> chrome://selenium-ide/content/tools.js -> file:///C:/Users/David%20Cunningham/Desktop/extensions_js/extensions.js, lineNumber -> 183, stack -> eval("http://example.com==\"http://example.com\"")@:0 ("http://example.com==\"http://example.com\"","label1")@chrome://selenium-ide/content/tools.js -> file:///C:/Users/David%20Cunningham/Desktop/extensions_js/extensions.js:183 ("http://example.com==\"http://example.com\"","label1")@chrome://selenium-ide/content/selenium/scripts/htmlutils.js:60 ([object Object],[object Object])@chrome://selenium-ide/content/selenium/scripts/selenium-commandhandlers.js:310 ()@chrome://selenium-ide/content/selenium/scripts/selenium-executionloop.js:112 (6)@chrome://selenium-ide/content/selenium/scripts/selenium-executionloop.js:78 (6)@chrome://selenium-ide/content/selenium/scripts/htmlutils.js:60 , name -> SyntaxError storeLocation should return a String so why am i getting this error, what is wrong with the syntax and how do I declare this command?

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  • signalR groups - connecting/disconnecting and sending - am I missing something?

    - by Terry_Brown
    very new to signalR, and have rolled up a very simple app that will take questions for moderation at conferences (felt like a straight forward use case) I have 2 hubs at the moment: - Question (for asking questions) - Speaker (these should receive questions and allow moderation, but that will come later) Solution lives at https://github.com/terrybrown/InterASK After watching a video (by David Fowler/Damian Edwards) (http://channel9.msdn.com/Shows/Web+Camps+TV/Damian-Edwards-and-David-Fowler-Demonstrate-SignalR) and another that I can't find the URL for atm, I thought I'd go with 'groups' as the concept to keep messages flowing to the right people. I implemented IConnected, IDisconnect as I'd seen in one of the videos, and upon debugging I can see Connect fire (and on reload I can see disconnect fire), but it seems nothing I do adds a person to a group. The signalR documentation suggests "Groups are not persisted on the server so applications are responsible for keeping track of what connections are in what groups so things like group count can be achieved" which I guess is telling me that I need to keep some method (static or otherwise?) of tracking who is in a group? Certainly I don't seem able to send to groups currently, though I have no problem distributing to anyone currently connected to the app and implementing the same JS method (2 machines on the same page). I suspect I'm just missing something - I read a few of the other questions on here, but none of them seem to mention IConnected/IDisconnect, which tells me these are either new (and nobody is using them) or that they're old (and nobody is using them). I know this could be considered a subjective question, though what I'm looking for is just a simple means of managing the groups so that I can do what I want to - send a question from one hub, and have people connected to a different hub receive it - groups felt the cleanest solution for this? Many thanks folks. Terry

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  • linebreak in url with Bibtex and hyperref package

    - by Tim
    Why is this item not shown properly in my bibliography? @misc{ann, abstract = {ANN is an implbmentation of nearest neighbor search.}, author = {David M. Mount and Sunil Arya}, howpublished = {\url{http://www.cs.umd.edu/~mount/ANN/}}, keywords = {knn}, posted-at = {2010-04-08 00:05:04}, priority = {2}, title = {ANN.}, url = "http://www.cs.umd.edu/~mount/ANN/", year = {2008} } @misc{Nilsson96introductionto, author = {Nilsson, Nils J.}, citeulike-article-id = {6995464}, howpublished = {\url{http://robotics.stanford.edu/people/nilsson/mlbook.html}}, keywords = {*file-import-10-04-11}, posted-at = {2010-04-11 06:52:28}, priority = {2}, title = {Introduction to Machine Learning: An Early Draft of a Proposed Textbook.}, year = {1996} } EDIT: I am using \usepackage{hyperref}, not \usepackage{url}. I don't know what changes I just made made the first item appear properly now @misc{ann, abstract = {ANN is an implbmentation of nearest neighbor search.}, author = {David M. Mount and Sunil Arya}, howpublished = {\url{http://www.cs.umd.edu/~mount/ANN/}}, keywords = {ann}, posted-at = {2010-04-08 00:05:04}, priority = {2}, title = {The \textsc{A}pproximate \textsc{N}earest \textsc{N}eighbor \textsc{S}earching \textsc{L}ibrary.}, url = "http://www.cs.umd.edu/~mount/ANN/", year = {2008} } EDIT: Since I am using hyperref package, it produces error when using url package together with it. So the two cannot work together? I would like to use hyper links inside pdf file, so I would like to use hyperref package instead of url package. I googled a bit, and try \usepackage[hyperindex,breaklinks]{hyperref}, but there is still no line break just as before. How can I do it? Is there conflict in the packages that I am now using?: \usepackage{amsmath} \usepackage{amsfonts} \usepackage[dvips]{graphicx} \usepackage{wrapfig} \graphicspath{{./figs/}} \DeclareGraphicsExtensions{.eps} \usepackage{fixltx2e} \usepackage{array} \usepackage{times} \usepackage{fancyhdr} \usepackage{multirow} \usepackage{algorithmic} \usepackage{algorithm} \usepackage{slashbox} \usepackage{multirow} \usepackage{rotating} \usepackage{longtable} \usepackage[hyperindex,breaklinks]{hyperref} \usepackage{forloop} \usepackage{lscape} \usepackage{supertabular} \usepackage{amssymb} \usepackage{amsthm}

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  • XML Attributes or Element Nodes?

    - by Camsoft
    Example XML using element nodes: <?xml version="1.0" encoding="utf-8"?> <users> <user> <name>David Smith</name> <phone>0441 234443</phone> <email>[email protected]</email> <addresses> <address> <street>1 Some Street</street> <town>Toy Town</town> <country>UK</country> </address> <address> <street>5 New Street</street> <town>Lego City</town> <country>US</country> </address> </addresses> </user> </users> Example XML using attributes: <?xml version="1.0" encoding="utf-8"?> <users> <user name="David Smith" phone="0441 234443" email="[email protected]"> <addresses> <address street="1 Some Street" town="Toy Town" country="UK" /> <address street="5 New Street" town="Lego City" country="US" /> </addresses> </user> </users> I'm needing to build an XML file based on data from a relation database and can't work out whether I should use attributes or elements. What is best practice when building XML files?

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  • passing value of index number to different php file.

    - by tooepic
    hi, i am a php beginner and have a question for you please. i have a text file with list of first and last names like this: john,smith sam,lewis david,davidson mike,anderson in my sort.php file, it sorts that name list by first name in ascending order with index number, which will display like this: 1. david,davidson 2. john,smith 3. mike,anderson 4. sam,lewis also, in that sort.php file, there's a form for input type=text where you can type index number and a button to delete that index number entered in that text field: <form action="deletename.php" method="post"> <table> <tr valign="top"> <td>Delete: <input type="text" size="2" name="indexnumber" /> </td> <td> <div align="left"> <input type="submit" name="delete" value="Delete" /> </div> </td> </tr> </table> </form> now the question...is there anything i can do in that form to send the value of that index number i entered in the text field? in other word...if i enter 3, what can i do to that form to send the value "mike,anderson" to deletename.php? thanks in advance.

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  • awk + sorting file according to values in the file and write two diffrent files

    - by yael
    hi I have in file file_test values of right eye and left eye How to separate the file_test to file1 and file2 by awk in order to write the equal values on file1 and different values on file2 as the following example down THX file_test: NAME: jim LAST NAME: bakker right eye: |5|< left eye VALUE: |5|< NAME: Jorg LAST NAME: mitchel right eye: |3|< left eye VALUE: |5|< NAME: jimmy LAST NAME: kartter right eye: |6|< left eye VALUE: |5|< NAME: david LAST NAME: kann right eye: |9|< left eye VALUE: |9|< file1: NAME: jim LAST NAME: bakker right eye: |5|< left eye VALUE: |5|< NAME: david LAST NAME: kann right eye: |9|< left eye VALUE: |9|< file2: NAME: Jorg LAST NAME: mitchel right eye: |3|< left eye VALUE: |5|< NAME: jimmy LAST NAME: kartter right eye: |6|< left eye VALUE: |5|<

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  • scheme struct question

    - by qzar
    ;; definition of the structure "book" ;; author: string - the author of the book ;; title: string - the title of the book ;; genre: symbol - the genre (define-struct book (author title genre)) (define lotr1 (make-book "John R. R. Tolkien" "The Fellowship of the Ring" 'Fantasy)) (define glory (make-book "David Brin" "Glory Season" 'ScienceFiction)) (define firstFamily (make-book "David Baldacci" "First Family" 'Thriller)) (define some-books (list lotr1 glory firstFamily)) ;; count-books-for-genre: symbol (list of books) -> number ;; the procedure takes a symbol and a list of books and produces the number ;; of books from the given symbol and genre ;; example: (count-books-for-genre 'Fantasy some-books) should produce 1 (define (count-books-for-genre genre lob) (if (empty? lob) 0 (if (symbol=? (book-genre (first lob)) genre) (+ 1 (count-books-for-genre (rest lob) genre)) (count-books-for-genre (rest lob) genre) ) ) ) (count-books-for-genre 'Fantasy some-books) It produce following exception first: expected argument of type non-empty list; given 'Fantasy, I don't understand whats the problem. Can somebody give me some explanation ? Thank you very much !

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  • Python DictReader - Skipping rows with missing columns?

    - by victorhooi
    heya, I have a Excel .CSV file I'm attempting to read in with DictReader. All seems to be well, except it seems to omit rows, specifically those with missing columns. Our input looks like: mail,givenName,sn,lorem,ipsum,dolor,telephoneNumber [email protected],ian,bay,3424,8403,2535,+65(2)34523534545 [email protected],mike,gibson,3424,8403,2535,+65(2)34523534545 [email protected],ross,martin,,,,+65(2)34523534545 david[email protected],david,connor,,,,+65(2)34523534545 [email protected],chris,call,3424,8403,2535,+65(2)34523534545 So some of the rows have missing lorem/ipsum/dolor columns, and it's just a string of commas for those. We're reading it in with: def read_gd_dump(input_file="blah 20100423.csv"): gd_extract = csv.DictReader(open('blah 20100423.csv'), restval='missing', dialect='excel') return dict([(row['something'], row) for row in gd_extract]) And I checked that "something" (the key for our dict) isn't one of the missing columns, I had originally suspected it might be that. It's one of the columns after that. However, DictReader seems to completely skip over the rows. I tried setting restval to something, didn't seem to make any difference. I can't seem to find anything in Python's CSV docs (http://docs.python.org/library/csv.html) that would explain this behaviour, but I may have misread something. Any ideas? Thanks, Victor

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  • LINQ XML query at c# wp7

    - by Karloss
    I am working at Windows Phone 7 C#, Xaml, XML and LINQ programming. I need to organize search by part of the name at following XML: <Row> <Myday>23</Myday> <Mymonth>12</Mymonth> <Mynames>Alex, Joanna, Jim</Mynames> </Row> <Row> <Myday>24</Myday> <Mymonth>12</Mymonth> <Mynames>John, David</Mynames> </Row> I have following query: var myData = from query in loadedData.Descendants("Row") where query.Element("Mynames").Value.Contains("Jo") select new Kalendars { Myday = (int)query.Element("Myday"), Mymonth = (int)query.Element("Mymonth"), Mynames = (string)query.Element("Mynames") }; listBoxSearch.ItemsSource = myData; Query problem is, that it will return full part of the names like "Alex, Joanna, Jim" and "John, David". How can i get only Joanna and John? Second question is how it is possible to do that user enters ...Value.Contains("jo") and query still returns Joanna and John? Possible solution (needs some corrections) public string Search_names { get { return search_names; } set { string line = this.Mynames; string[] names = line.Split(new[] { ", " }, StringSplitOptions.None); var jos = from name in names where name.Contains("is") select name; // ["Joanna"] // HOW TO BIND search_names? } }

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  • How do I render *parts* of a svg file?

    - by Fake Code Monkey Rashid
    Hello good people! :) I want to render parts of a svg file by name but for the life of me I cannot figure out how to do so (using python + gtk). Here's the svg file in question: http://david.bellot.free.fr/svg-cards/files/SVG-cards-2.0.1.tar.gz On his site, David, says: You can draw a card either by rendering the file onto a pixmap and clipping each card manually or by using the card's name through a DOM interface. All cards are embedded into a SVG group. I don't know what he means by a DOM interface. I have done some searching and the best result I found that seems to fit what I want to do is: QSvgRenderer *renderer = new QSvgRenderer(QLatin1String("SvgCardDeck.svg")); QGraphicsSvgItem *black = new QGraphicsSvgItem(); QGraphicsSvgItem *red = new QGraphicsSvgItem(); black->setSharedRenderer(renderer); black->setElementId(QLatin1String("black_joker")); red->setSharedRenderer(renderer); red->setElementId(QLatin1String("red_joker")); Notice however that it is for Qt and is not even written in python. This is what I have so far: #!/usr/bin/env python from __future__ import absolute_import import cairo import gtk import rsvg from xml import xpath from xml.dom import minidom window = gtk.Window() window.set_title("Foo") window.set_size_request(256, 256) window.set_property("resizable", False) window.set_position(gtk.WIN_POS_CENTER) window.connect("destroy", gtk.main_quit) window.show() document = minidom.parse("cards.svg") element = xpath.Evaluate("//*[@id='1_club']", document)[0] xml = element.toxml() svg = rsvg.Handle() svg.write(xml) pixbuf = svg.get_pixbuf() image = gtk.Image() image.set_from_pixbuf(pixbuf) image.show() window.add(image) gtk.main() It doesn't work, of course. What am I missing?

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  • Inject App Settings using Windsor

    - by Damian Powell
    How can I inject the value of an appSettings entry (from app.config or web.config) into a service using the Windsor container? If I wanted to inject the value of a Windsor property into a service, I would do something like this: <properties> <importantIntegerProperty>666</importantIntegerProperty> </properties> <component id="myComponent" service="MyApp.IService, MyApp" type="MyApp.Service, MyApp" > <parameters> <importantInteger>#{importantIntegerProperty}</importantInteger> </parameters> </component> However, what I'd really like to do is take the value represented by #{importantIntegerProperty} from an app settings variable which might be defined like this: <appSettings> <add key="importantInteger" value="666"/> </appSettings> EDIT: To clarify; I realise that this is not natively possible with Windsor and the David Hayden article that sliderhouserules refers to is actually about his own (David Hayden's) IoC container, not Windsor. I'm surely not the first person to have this problem so what I'd like to know is how have other people solved this issue?

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  • Strange LINQ to SQL Behavior

    - by mcass20
    What is wrong with the last query? Is it a bug or am I missing something? This query returns 2 records (correct): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>David</value>%")); This query returns 2 records (correct): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>%David%</value>%")); This query returns 0 records (correct): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>av</value>%")); This query returns 2 records (correct): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>%av%</value>%")); This query returns 0 records (correct): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>v</value>%")); This query returns 15 records (incorrect, should return 2): query = query.Where(Log => SqlMethods.Like(Log.FormattedMessage, "%<key>Name</key><value>%v%</value>%"));

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  • Silverlight Tree View with Multiple Levels

    - by psheriff
    There are many examples of the Silverlight Tree View that you will find on the web, however, most of them only show you how to go to two levels. What if you have more than two levels? This is where understanding exactly how the Hierarchical Data Templates works is vital. In this blog post, I am going to break down how these templates work so you can really understand what is going on underneath the hood. To start, let’s look at the typical two-level Silverlight Tree View that has been hard coded with the values shown below: <sdk:TreeView>  <sdk:TreeViewItem Header="Managers">    <TextBlock Text="Michael" />    <TextBlock Text="Paul" />  </sdk:TreeViewItem>  <sdk:TreeViewItem Header="Supervisors">    <TextBlock Text="John" />    <TextBlock Text="Tim" />    <TextBlock Text="David" />  </sdk:TreeViewItem></sdk:TreeView> Figure 1 shows you how this tree view looks when you run the Silverlight application. Figure 1: A hard-coded, two level Tree View. Next, let’s create three classes to mimic the hard-coded Tree View shown above. First, you need an Employee class and an EmployeeType class. The Employee class simply has one property called Name. The constructor is created to accept a “name” argument that you can use to set the Name property when you create an Employee object. public class Employee{  public Employee(string name)  {    Name = name;  }   public string Name { get; set; }} Finally you create an EmployeeType class. This class has one property called EmpType and contains a generic List<> collection of Employee objects. The property that holds the collection is called Employees. public class EmployeeType{  public EmployeeType(string empType)  {    EmpType = empType;    Employees = new List<Employee>();  }   public string EmpType { get; set; }  public List<Employee> Employees { get; set; }} Finally we have a collection class called EmployeeTypes created using the generic List<> class. It is in the constructor for this class where you will build the collection of EmployeeTypes and fill it with Employee objects: public class EmployeeTypes : List<EmployeeType>{  public EmployeeTypes()  {    EmployeeType type;            type = new EmployeeType("Manager");    type.Employees.Add(new Employee("Michael"));    type.Employees.Add(new Employee("Paul"));    this.Add(type);     type = new EmployeeType("Project Managers");    type.Employees.Add(new Employee("Tim"));    type.Employees.Add(new Employee("John"));    type.Employees.Add(new Employee("David"));    this.Add(type);  }} You now have a data hierarchy in memory (Figure 2) which is what the Tree View control expects to receive as its data source. Figure 2: A hierachial data structure of Employee Types containing a collection of Employee objects. To connect up this hierarchy of data to your Tree View you create an instance of the EmployeeTypes class in XAML as shown in line 13 of Figure 3. The key assigned to this object is “empTypes”. This key is used as the source of data to the entire Tree View by setting the ItemsSource property as shown in Figure 3, Callout #1. Figure 3: You need to start from the bottom up when laying out your templates for a Tree View. The ItemsSource property of the Tree View control is used as the data source in the Hierarchical Data Template with the key of employeeTypeTemplate. In this case there is only one Hierarchical Data Template, so any data you wish to display within that template comes from the collection of Employee Types. The TextBlock control in line 20 uses the EmpType property of the EmployeeType class. You specify the name of the Hierarchical Data Template to use in the ItemTemplate property of the Tree View (Callout #2). For the second (and last) level of the Tree View control you use a normal <DataTemplate> with the name of employeeTemplate (line 14). The Hierarchical Data Template in lines 17-21 sets its ItemTemplate property to the key name of employeeTemplate (Line 19 connects to Line 14). The source of the data for the <DataTemplate> needs to be a property of the EmployeeTypes collection used in the Hierarchical Data Template. In this case that is the Employees property. In the Employees property there is a “Name” property of the Employee class that is used to display the employee name in the second level of the Tree View (Line 15). What is important here is that your lowest level in your Tree View is expressed in a <DataTemplate> and should be listed first in your Resources section. The next level up in your Tree View should be a <HierarchicalDataTemplate> which has its ItemTemplate property set to the key name of the <DataTemplate> and the ItemsSource property set to the data you wish to display in the <DataTemplate>. The Tree View control should have its ItemsSource property set to the data you wish to display in the <HierarchicalDataTemplate> and its ItemTemplate property set to the key name of the <HierarchicalDataTemplate> object. It is in this way that you get the Tree View to display all levels of your hierarchical data structure. Three Levels in a Tree View Now let’s expand upon this concept and use three levels in our Tree View (Figure 4). This Tree View shows that you now have EmployeeTypes at the top of the tree, followed by a small set of employees that themselves manage employees. This means that the EmployeeType class has a collection of Employee objects. Each Employee class has a collection of Employee objects as well. Figure 4: When using 3 levels in your TreeView you will have 2 Hierarchical Data Templates and 1 Data Template. The EmployeeType class has not changed at all from our previous example. However, the Employee class now has one additional property as shown below: public class Employee{  public Employee(string name)  {    Name = name;    ManagedEmployees = new List<Employee>();  }   public string Name { get; set; }  public List<Employee> ManagedEmployees { get; set; }} The next thing that changes in our code is the EmployeeTypes class. The constructor now needs additional code to create a list of managed employees. Below is the new code. public class EmployeeTypes : List<EmployeeType>{  public EmployeeTypes()  {    EmployeeType type;    Employee emp;    Employee managed;     type = new EmployeeType("Manager");    emp = new Employee("Michael");    managed = new Employee("John");    emp.ManagedEmployees.Add(managed);    managed = new Employee("Tim");    emp.ManagedEmployees.Add(managed);    type.Employees.Add(emp);     emp = new Employee("Paul");    managed = new Employee("Michael");    emp.ManagedEmployees.Add(managed);    managed = new Employee("Sara");    emp.ManagedEmployees.Add(managed);    type.Employees.Add(emp);    this.Add(type);     type = new EmployeeType("Project Managers");    type.Employees.Add(new Employee("Tim"));    type.Employees.Add(new Employee("John"));    type.Employees.Add(new Employee("David"));    this.Add(type);  }} Now that you have all of the data built in your classes, you are now ready to hook up this three-level structure to your Tree View. Figure 5 shows the complete XAML needed to hook up your three-level Tree View. You can see in the XAML that there are now two Hierarchical Data Templates and one Data Template. Again you list the Data Template first since that is the lowest level in your Tree View. The next Hierarchical Data Template listed is the next level up from the lowest level, and finally you have a Hierarchical Data Template for the first level in your tree. You need to work your way from the bottom up when creating your Tree View hierarchy. XAML is processed from the top down, so if you attempt to reference a XAML key name that is below where you are referencing it from, you will get a runtime error. Figure 5: For three levels in a Tree View you will need two Hierarchical Data Templates and one Data Template. Each Hierarchical Data Template uses the previous template as its ItemTemplate. The ItemsSource of each Hierarchical Data Template is used to feed the data to the previous template. This is probably the most confusing part about working with the Tree View control. You are expecting the content of the current Hierarchical Data Template to use the properties set in the ItemsSource property of that template. But you need to look to the template lower down in the XAML to see the source of the data as shown in Figure 6. Figure 6: The properties you use within the Content of a template come from the ItemsSource of the next template in the resources section. Summary Understanding how to put together your hierarchy in a Tree View is simple once you understand that you need to work from the bottom up. Start with the bottom node in your Tree View and determine what that will look like and where the data will come from. You then build the next Hierarchical Data Template to feed the data to the previous template you created. You keep doing this for each level in your Tree View until you get to the last level. The data for that last Hierarchical Data Template comes from the ItemsSource in the Tree View itself. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “Silverlight TreeView with Multiple Levels” from the drop down list.

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