tips and tricks - Page 250

What is the best way to solve an Objective-C namespace collision?

- by Mecki

Objective-C has no namespaces; it's much like C, everything is within one global namespace. Common practice is to prefix classes with initials, e.g. if you are working at IBM, you could prefix them with "IBM"; if you work for Microsoft, you could use "MS"; and so on. Sometimes the initials refer to the project, e.g. Adium prefixes classes with "AI" (as there is no company behind it of that you could take the initials). Apple prefixes classes with NS and says this prefix is reserved for Apple only. So far so well. But appending 2 to 4 letters to a class name in front is a very, very limited namespace. E.g. MS or AI could have an entirely different meanings (AI could be Artificial Intelligence for example) and some other developer might decide to use them and create an equally named class. Bang, namespace collision. Okay, if this is a collision between one of your own classes and one of an external framework you are using, you can easily change the naming of your class, no big deal. But what if you use two external frameworks, both frameworks that you don't have the source to and that you can't change? Your application links with both of them and you get name conflicts. How would you go about solving these? What is the best way to work around them in such a way that you can still use both classes? In C you can work around these by not linking directly to the library, instead you load the library at runtime, using dlopen(), then find the symbol you are looking for using dlsym() and assign it to a global symbol (that you can name any way you like) and then access it through this global symbol. E.g. if you have a conflict because some C library has a function named open(), you could define a variable named myOpen and have it point to the open() function of the library, thus when you want to use the system open(), you just use open() and when you want to use the other one, you access it via the myOpen identifier. Is something similar possible in Objective-C and if not, is there any other clever, tricky solution you can use resolve namespace conflicts? Any ideas? Update: Just to clarify this: answers that suggest how to avoid namespace collisions in advance or how to create a better namespace are certainly welcome; however, I will not accept them as the answer since they don't solve my problem. I have two libraries and their class names collide. I can't change them; I don't have the source of either one. The collision is already there and tips on how it could have been avoided in advance won't help anymore. I can forward them to the developers of these frameworks and hope they choose a better namespace in the future, but for the time being I'm searching a solution to work with the frameworks right now within a single application. Any solutions to make this possible?

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How can I optimize this subqueried and Joined MySQL Query?

- by kevzettler

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How to bind to the sum of two data bound values in WPF?

- by Sheridan

I have designed an analog clock control. It uses the stroke from two ellipses to represent an outer border and an inner border to the clock face. I have exposed properties in the UserControl that allow a user to alter the thickness of these two borders. The Ellipse.StrokeThickness properties are then bound to these UserControl properties. At the moment, I am binding the UserControl property for the outer border thickness to the margins of the inner elements so that they are not hidden when the border size is increased. <Ellipse Name="OuterBorder" Panel.ZIndex="1" StrokeThickness="{Binding OuterBorderThickness, ElementName=This}" Stroke="{StaticResource OuterBorderBrush}" /> <Ellipse Name="InnerBorder" Panel.ZIndex="5" StrokeThickness="{Binding InnerBorderThickness, ElementName=This}" Margin="{Binding OuterBorderThickness, ElementName=This}" Stroke="{StaticResource InnerBorderBrush}"> ... <Ellipse Name="Face" Panel.ZIndex="1" Margin="{Binding OuterBorderThickness, ElementName=This}" Fill="{StaticResource FaceBackgroundBrush}" /> ... The problem is that if the inner border thickness is increased, this does not affect the margins and so the hour ticks and numbers can become partially obscured or hidden. So what I really need is to be able to bind the margin properties of the inner controls to the sum of the inner and outer border thickness values (they are of type double). I have done this successfully using 'DataContext = this;', but am trying to rewrite the control without this as I hear it is not recommended. I also thought about using a converter and passing the second value as the ConverterParameter, but didn't know how to bind to the ConverterParameter. Any tips would be greatly appreciated. EDIT Thanks to Kent's suggestion, I've created a simple MultiConverter to add the input values and return the result. I've hooked the SAME multibinding with converter XAML to both a TextBlock.Text property and the TextBlock.Margin property to test it. <TextBlock> <TextBlock.Text> <MultiBinding Converter="{StaticResource SumConverter}" ConverterParameter="Add"> <Binding Path="OuterBorderThickness" ElementName="This" /> <Binding Path="InnerBorderThickness" ElementName="This" /> </MultiBinding> </TextBlock.Text> <TextBlock.Margin> <MultiBinding Converter="{StaticResource SumConverter}" ConverterParameter="Add"> <Binding Path="OuterBorderThickness" ElementName="This" /> <Binding Path="InnerBorderThickness" ElementName="This" /> </MultiBinding> </TextBlock.Margin> </TextBlock> I can see the correct value displayed in the TexBlock, but the Margin is not set. Any ideas? EDIT Interestingly, the Margin property can be bound to a data property of type double, but this does not seem to apply within a MultiBinding. As advised by Kent, I changed the Converter to return the value as a Thickness object and now it works. Thanks Kent.

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Drupal 7 Forms API Conditional Logic not working in IE

- by Francis Yaconiello

I have a drupal 7 form with a bunch of fields: $form['account_type'] = array( '#title' => t('Utility Account Type'), '#type' => 'select', '#options' => necp_enrollment_administration_portal_account_type_options(), '#required' => TRUE, '#default_value' => isset($form_state['values']['account_type']) ? $form_state['values']['account_type'] : '', ); // Should show if account_type = 1 $form['home_wrapper'] = array( '#type' => 'fieldset', '#states' => array( 'visible' => array( ':input[name="account_type"]' => array('value' => 1), ), ), ); $form['home_wrapper']['first_name_1'] = array( '#title' => t('Primary Account First Name'), '#type' => 'textfield', '#default_value' => isset($form_state['values']['first_name_1']) ? $form_state['values']['first_name_1'] : '', '#states' => array( 'required' => array( ':input[name="account_type"]' => array('value' => 1), ), ), ); $form['home_wrapper']['last_name_1'] = array( '#title' => t('Primary Account Last Name'), '#type' => 'textfield', '#default_value' => isset($form_state['values']['last_name_1']) ? $form_state['values']['last_name_1'] : '', '#states' => array( 'required' => array( ':input[name="account_type"]' => array('value' => 1), ), ), ); // Should show if account_type = 2 $form['business_wrapper'] = array( '#type' => 'fieldset', '#states' => array( 'visible' => array( ':input[name="account_type"]' => array('value' => 2), ), ), ); $form['business_wrapper']['company_name'] = array( '#title' => t('Company/Organization'), '#type' => 'textfield', '#default_value' => isset($form_state['values']['company_name']) ? $form_state['values']['company_name'] : '', '#states' => array( 'required' => array( ':input[name="account_type"]' => array('value' => 2), ), ), ); In Firefox/Chrome/Opera all versions this form behaves as it should. However in all versions of IE the form initializes with display:none; style on all of the conditional fields regardless of what the value in account_type is. Changing the selected option of account_type does not effect the hidden status. Any tips on debugging this form would be awesome. Notes: I am not much of a Drupal developer, I inherited this site. Just trying to iron out the last couple bugs so we can go live there are more fields than are listed above, I just gave you some of the applicable ones so that you could get the gist of how my forms were setup current url for the form in development: https://northeastcleanpower.com/enroll_new I'm using http://www.browserstack.com/ to debug IE 7 - 10pp4 (I think we only have to support 8 and up though) I've also tried: ':select[name="account_type"]' => array('value' => 1), '#edit-account-type' => array('value' => 1),

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(Ordered) Set Partitions in fixed-size Blocks

- by Eugen

Here is a function I would like to write but am unable to do so. Even if you don't / can't give a solution I would be grateful for tips. For example, I know that there is a correlation between the ordered represantions of the sum of an integer and ordered set partitions but that alone does not help me in finding the solution. So here is the description of the function I need: The Task Create an efficient* function List<int[]> createOrderedPartitions(int n_1, int n_2,..., int n_k) that returns a list of arrays of all set partions of the set {0,...,n_1+n_2+...+n_k-1} in number of arguments blocks of size (in this order) n_1,n_2,...,n_k (e.g. n_1=2, n_2=1, n_3=1 -> ({0,1},{3},{2}),...). Here is a usage example: int[] partition = createOrderedPartitions(2,1,1).get(0); partition[0]; // -> 0 partition[1]; // -> 1 partition[2]; // -> 3 partition[3]; // -> 2 Note that the number of elements in the list is (n_1+n_2+...+n_n choose n_1) * (n_2+n_3+...+n_n choose n_2) * ... * (n_k choose n_k). Also, createOrderedPartitions(1,1,1) would create the permutations of {0,1,2} and thus there would be 3! = 6 elements in the list. * by efficient I mean that you should not initially create a bigger list like all partitions and then filter out results. You should do it directly. Extra Requirements If an argument is 0 treat it as if it was not there, e.g. createOrderedPartitions(2,0,1,1) should yield the same result as createOrderedPartitions(2,1,1). But at least one argument must not be 0. Of course all arguments must be = 0. Remarks The provided pseudo code is quasi Java but the language of the solution doesn't matter. In fact, as long as the solution is fairly general and can be reproduced in other languages it is ideal. Actually, even better would be a return type of List<Tuple<Set>> (e.g. when creating such a function in Python). However, then the arguments wich have a value of 0 must not be ignored. createOrderedPartitions(2,0,2) would then create [({0,1},{},{2,3}),({0,2},{},{1,3}),({0,3},{},{1,2}),({1,2},{},{0,3}),...] Background I need this function to make my mastermind-variation bot more efficient and most of all the code more "beautiful". Take a look at the filterCandidates function in my source code. There are unnecessary / duplicate queries because I'm simply using permutations instead of specifically ordered partitions. Also, I'm just interested in how to write this function. My ideas for (ugly) "solutions" Create the powerset of {0,...,n_1+...+n_k}, filter out the subsets of size n_1, n_2 etc. and create the cartesian product of the n subsets. However this won't actually work because there would be duplicates, e.g. ({1,2},{1})... First choose n_1 of x = {0,...,n_1+n_2+...+n_n-1} and put them in the first set. Then choose n_2 of x without the n_1 chosen elements beforehand and so on. You then get for example ({0,2},{},{1,3},{4}). Of course, every possible combination must be created so ({0,4},{},{1,3},{2}), too, and so on. Seems rather hard to implement but might be possible. Research I guess this goes in the direction I want however I don't see how I can utilize it for my specific scenario. http://rosettacode.org/wiki/Combinations

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Binding Entity Framework Collections Simply Using ASP.NET MVC

- by jpcmorton

To begin with: Using Entity Framework v4.0. ASP.NET MVC 2.0. Visual Studio 2010. I have a model that consists simply of an order & order items. What I want to do is simply bind that model without too much hassle where possible (avoiding type converters, etc). Simply the model looks like this: public class Order { public int ID { get; set; } public string OrderNumber { get; set; } public EntityCollection<OrderItem> Items { get; set; } } public class OrderItem { public int ID { get; set; } public string Qty { get; set; } } This is as simple as I want to keep it. This model is coming directly from the code generated by the entity framework generator. I would prefer to use the model directly from the entity framework (I know there are views saying this is a bad thing, but alas). I then have the View looking like this: <% using (Html.BeginForm()) {%> <%: Html.ValidationSummary(true) %> <fieldset> <legend>Fields</legend> <div class="editor-label"> <%: Html.LabelFor(model => model.ID) %> </div> <div class="editor-field"> <%: Html.TextBoxFor(model => model.ID) %> <%: Html.ValidationMessageFor(model => model.ID) %> </div> <div class="editor-label"> <%: Html.LabelFor(model => model.OrderNumber) %> </div> <div class="editor-field"> <%: Html.TextBoxFor(model => model.OrderNumber)%> <%: Html.ValidationMessageFor(model => model.OrderNumber)%> </div> <div id="lineItems"> Where I need to put my line items to be edited, inserted </div> <p> <input type="submit" value="Create" /> </p> </fieldset> <% } %> What I want to do is have a situation where I can use dynamic line items (using javascript). Problems are this: How to go about inserting the initial line item (within the lineItems div). This need to be strongly typed and use the built in validation framework of MVC. Best way to go about inserting line items dynamically so that on the postback there is a complete bind to the model without too much messing around (id = 1,2,3,4, etc). Any help, examples, tips, etc would be appreciated.

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Using LINQ to create a simple login

- by JDWebs

I'm an C# ASP.NET beginner, so please excuse anything that's... not quite right! In short, I want to create a really basic login system: one which runs through a database and uses sessions so that only logged in users can access certain pages. I know how to do most of that, but I'm stuck with querying data with LINQ on the login page. On the login page, I have a DropDownList to select a username, a Textbox to type in a password and a button to login (I also have a literal for errors). The DropDownList is databound to a datatable called DT_Test. DT_Test contains three columns: UsernameID (int), Username (nchar(30)) and Password (nchar(30)). UsernameID is the primary key. I want to make the button's click event query data from the database with the DropDownList and Textbox, in order to check if the username and password match. But I don't know how to do this... Current Code (not a lot!): Front End: <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Login_Test.aspx.cs" Inherits="Login_Login_Test" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title>Login Test</title> </head> <body> <form id="LoginTest" runat="server"> <div> <asp:DropDownList ID="DDL_Username" runat="server" Height="20px" DataTextField="txt"> </asp:DropDownList> <br /> <asp:TextBox ID="TB_Password" runat="server" TextMode="Password"></asp:TextBox> <br /> <asp:Button ID="B_Login" runat="server" onclick="B_Login_Click" Text="Login" /> <br /> <asp:Literal ID="LI_Result" runat="server"></asp:Literal> </div> </form> </body> </html> Back End: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public partial class Login_Login_Test : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { Binder(); } } private void Binder() { using (DataClassesDataContext db = new DataClassesDataContext()) { DDL_Username.DataSource = from x in db.DT_Honeys select new { x.UsernameID, txt = x.Username }; DDL_Username.DataBind(); } } protected void B_Login_Click(object sender, EventArgs e) { if (TB_Password.Text != "") { using (DataClassesDataContext db = new DataClassesDataContext()) { } } } } I have spent hours searching and trying different code, but none of it seems to fit in for this context. Anyway, help and tips appreciated, thank you very much! I am aware of security risks etc. but this is not a live website or anything, it is simply for testing purposes as a beginner. *

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C++ file input/output search

- by Brian J

Hi I took the following code from a program I'm writing to check a user generated string against a dictionary as well as other validation. My problem is that although my dictionary file is referenced correctly,the program gives the default "no dictionary found".I can't see clearly what I'm doing in error here,if anyone has any tips or pointers it would be appreciated, Thanks. //variables for checkWordInFile #define gC_FOUND 99 #define gC_NOT_FOUND -99 // static bool certifyThat(bool condition, const char* error) { if(!condition) printf("%s", error); return !condition; } //method to validate a user generated password following password guidelines. void validatePass() { FILE *fptr; char password[MAX+1]; int iChar,iUpper,iLower,iSymbol,iNumber,iTotal,iResult,iCount; //shows user password guidelines printf("\n\n\t\tPassword rules: "); printf("\n\n\t\t 1. Passwords must be at least 9 characters long and less than 15 characters. "); printf("\n\n\t\t 2. Passwords must have at least 2 numbers in them."); printf("\n\n\t\t 3. Passwords must have at least 2 uppercase letters and 2 lowercase letters in them."); printf("\n\n\t\t 4. Passwords must have at least 1 symbol in them (eg ?, $, £, %)."); printf("\n\n\t\t 5. Passwords may not have small, common words in them eg hat, pow or ate."); //gets user password input get_user_password: printf("\n\n\t\tEnter your password following password rules: "); scanf("%s", &password); iChar = countLetters(password,&iUpper,&iLower,&iSymbol,&iNumber,&iTotal); iUpper = countLetters(password,&iUpper,&iLower,&iSymbol,&iNumber,&iTotal); iLower =countLetters(password,&iUpper,&iLower,&iSymbol,&iNumber,&iTotal); iSymbol =countLetters(password,&iUpper,&iLower,&iSymbol,&iNumber,&iTotal); iNumber = countLetters(password,&iUpper,&iLower,&iSymbol,&iNumber,&iTotal); iTotal = countLetters(password,&iUpper,&iLower,&iSymbol,&iNumber,&iTotal); if(certifyThat(iUpper >= 2, "Not enough uppercase letters!!!\n") || certifyThat(iLower >= 2, "Not enough lowercase letters!!!\n") || certifyThat(iSymbol >= 1, "Not enough symbols!!!\n") || certifyThat(iNumber >= 2, "Not enough numbers!!!\n") || certifyThat(iTotal >= 9, "Not enough characters!!!\n") || certifyThat(iTotal <= 15, "Too many characters!!!\n")) goto get_user_password; iResult = checkWordInFile("dictionary.txt", password); if(certifyThat(iResult != gC_FOUND, "Password contains small common 3 letter word/s.")) goto get_user_password; iResult = checkWordInFile("passHistory.txt",password); if(certifyThat(iResult != gC_FOUND, "Password contains previously used password.")) goto get_user_password; printf("\n\n\n Your new password is verified "); printf(password); //writing password to passHistroy file. fptr = fopen("passHistory.txt", "w"); // create or open the file for( iCount = 0; iCount < 8; iCount++) { fprintf(fptr, "%s\n", password[iCount]); } fclose(fptr); printf("\n\n\n"); system("pause"); }//end validatePass method int checkWordInFile(char * fileName,char * theWord){ FILE * fptr; char fileString[MAX + 1]; int iFound = -99; //open the file fptr = fopen(fileName, "r"); if (fptr == NULL) { printf("\nNo dictionary file\n"); printf("\n\n\n"); system("pause"); return (0); // just exit the program } /* read the contents of the file */ while( fgets(fileString, MAX, fptr) ) { if( 0 == strcmp(theWord, fileString) ) { iFound = -99; } } fclose(fptr); return(0); }//end of checkwORDiNFile

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What Good way to keep some different data in Cookies in asp.net?

- by Dmitriy

Hello! I want to keep some different data in one cookie file and write this class, and want to know - is this good? For example - user JS enable.When user open his first page on my site, i write to session his GMT time and write with this manager JS state. (GMT time is ajax request with js). And i want to keep some data in this cookie (up to 10 values). Have any advices or tips? /// <summary> /// CookiesSettings /// </summary> internal enum CookieSetting { IsJsEnable = 1, } internal class CookieSettingValue { public CookieSetting Type { get; set; } public string Value { get; set; } } /// <summary> /// Cookies to long time of expire /// </summary> internal class CookieManager { //User Public Settings private const string CookieValueName = "UPSettings"; private string[] DelimeterValue = new string[1] { "#" }; //cookie daat private List<CookieSettingValue> _data; public CookieManager() { _data = LoadFromCookies(); } #region Save and load /// <summary> /// Load from cookie string value /// </summary> private List<CookieSettingValue> LoadFromCookies() { if (!CookieHelper.RequestCookies.Contains(CookieValueName)) return new List<CookieSettingValue>(); _data = new List<CookieSettingValue>(); string data = CookieHelper.RequestCookies[CookieValueName].ToString(); string[] dels = data.Split(DelimeterValue, StringSplitOptions.RemoveEmptyEntries); foreach (string delValue in dels) { int eqIndex = delValue.IndexOf("="); if (eqIndex == -1) continue; int cookieType = ValidationHelper.GetInteger(delValue.Substring(0, eqIndex), 0); if (!Enum.IsDefined(typeof(CookieSetting), cookieType)) continue; CookieSettingValue value = new CookieSettingValue(); value.Type = (CookieSetting)cookieType; value.Value = delValue.Substring(eqIndex + 1, delValue.Length - eqIndex-1); _data.Add(value); } return _data; } public void Save() { CookieHelper.SetValue(CookieValueName, ToCookie(), DateTime.UtcNow.AddMonths(6)); } #endregion #region Get value public bool Bool(CookieSetting type, bool defaultValue) { CookieSettingValue inList = _data.SingleOrDefault(x => x.Type == type); if (inList == null) return defaultValue; return ValidationHelper.GetBoolean(inList.Value, defaultValue); } #endregion #region Set value public void SetValue(CookieSetting type, int value) { CookieSettingValue inList = _data.SingleOrDefault(x => x.Type == type); if (inList == null) { inList = new CookieSettingValue(); inList.Type = type; inList.Value = value.ToString(); _data.Add(inList); } else { inList.Value = value.ToString(); } } public void SetValue(CookieSetting type, bool value) { CookieSettingValue inList = _data.SingleOrDefault(x => x.Type == type); if (inList == null) { inList = new CookieSettingValue(); inList.Type = type; inList.Value = value.ToString(); _data.Add(inList); } else { inList.Value = value.ToString(); } } #endregion #region Private methods private string ToCookie() { StringBuilder sb = new StringBuilder(); for (int i = 0; i < _data.Count; i++) { sb.Append((int)_data[i].Type); sb.Append("="); sb.Append(_data[i].Value); sb.Append(DelimeterValue[0]); } return sb.ToString(); } /// <summary> /// Cookie length in bytes. Max - 4 bytes /// </summary> /// <returns></returns> private int GetLength() { return System.Text.Encoding.UTF8.GetByteCount(ToCookie()); } #endregion } P.S. i want to keep many data in one cookies file to compress data and decrease cookies count.

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Faulty to use memcache together with a php web-browser-game in this way?

- by Crowye

Background We are currently working on a strategy web-browser game based on php, html and javascript. The plan is to have 10,000+ users playing within the same world. Currently we are using memcached to: store json static data, language files store changeable serialized php class objects (such as armies, inventorys, unit-containers, buildings, etc) In the back we have a mysql server running and holding all the game data aswell. When a object is loaded through our ObjectLoader it loads in this order: checks a static hashmap in the script for the object checks memcache if it has already been loaded into it otherwise loads from database, and saves it into memcache and the static temp hashmap We have built the whole game using a class-object-oriented approach where functionality is always made between objects. Beause of this we think we have managed to get a nice structure, and with the help of memcached we have received good request times from client-server when interacting with the game. I'm aware that memcache is not synchronized, and also is not commonly used for holding a full game in memory. In the beginning after a server's startup the load times when loading objects into memcache for the first time will be high, but after the server's been online for a while and most loads are from memcache, the loads will be well reduced. Currently we are saving changed objects into memcache and database at the same time. Earlier we had an idea to save objects into db only after a certain time or at intervals, but due to risk inconsistency if the memcache/server went down, we skipped it for now. Client requests to server often return object's status simple json-format without changing the object, which in turn is represented in the browser visually with images and javascript. But from time to time depending on when an object was last updated, it updates them with new information (e.g. a build-queue holding planned buildings time-progress is increased, and/or planned-queue-items-array has changed). Questions: Do you see how this could work or are we walking in blindness here? Do you expect us to have a lot of inconsistency issues if someone loads and updates the a memcache objects while someone else does the same? Is it even doable to do it in the way he have done it? Seems to be working fine atm, but so far we have only been 4 people online at the same time.. Is some other cache program more fit for this class-object approach than memcached? Is there any other tips you have for this situation? UPDATE Since it is simply a "normal webpage" (no applet, flash, etc), we are implementing the game so that the server is the only one holding a "real game-state".. the state of the different javascript-objects on the client is more like a approximative version of the server's game state. From time to time and before you do certain things important things, the client's visual state is updated to the server's state (e.g. the client things he can afford a barracks, asks the server to build a barracks, server updates current resources according to income-data on server and then tries to build a barracks or casts an error-message, and then sends the current server-state on resources, buildings back to the client).. It is not a fast-paced game lika real strategy game. More like a quite slow 3-4 months playtime game, where buildings can take +1 minute up to several days to complete.

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Fastest way to pad a number in Java to a certain number of digits

- by Martin

Am trying to create a well-optimised bit of code to create number of X-digits in length (where X is read from a runtime properties file), based on a DB-generated sequence number (Y), which is then used a folder-name when saving a file. I've come up with three ideas so far, the fastest of which is the last one, but I'd appreciate any advice people may have on this... 1) Instantiate a StringBuilder with initial capacity X. Append Y. While length < X, insert a zero at pos zero. 2) Instantiate a StringBuilder with initial capacity X. While length < X, append a zero. Create a DecimalFormat based on StringBuilder value, and then format the number when it's needed. 3) Create a new int of Math.pow( 10, X ) and add Y. Use String.valueOf() on the new number and then substring(1) it. The second one can obviously be split into outside-loop and inside-loop sections. So, any tips? Using a for-loop of 10,000 iterations, I'm getting similar timings from the first two, and the third method is approximately ten-times faster. Does this seem correct? Full test-method code below... // Setup test variables int numDigits = 9; int testNumber = 724; int numIterations = 10000; String folderHolder = null; DecimalFormat outputFormat = new DecimalFormat( "#,##0" ); // StringBuilder test long before = System.nanoTime(); for ( int i = 0; i < numIterations; i++ ) { StringBuilder sb = new StringBuilder( numDigits ); sb.append( testNumber ); while ( sb.length() < numDigits ) { sb.insert( 0, 0 ); } folderHolder = sb.toString(); } long after = System.nanoTime(); System.out.println( "01: " + outputFormat.format( after - before ) + " nanoseconds" ); System.out.println( "Sanity check: Folder = \"" + folderHolder + "\"" ); // DecimalFormat test before = System.nanoTime(); StringBuilder sb = new StringBuilder( numDigits ); while ( sb.length() < numDigits ) { sb.append( 0 ); } DecimalFormat formatter = new DecimalFormat( sb.toString() ); for ( int i = 0; i < numIterations; i++ ) { folderHolder = formatter.format( testNumber ); } after = System.nanoTime(); System.out.println( "02: " + outputFormat.format( after - before ) + " nanoseconds" ); System.out.println( "Sanity check: Folder = \"" + folderHolder + "\"" ); // Substring test before = System.nanoTime(); int baseNum = (int)Math.pow( 10, numDigits ); for ( int i = 0; i < numIterations; i++ ) { int newNum = baseNum + testNumber; folderHolder = String.valueOf( newNum ).substring( 1 ); } after = System.nanoTime(); System.out.println( "03: " + outputFormat.format( after - before ) + " nanoseconds" ); System.out.println( "Sanity check: Folder = \"" + folderHolder + "\"" );

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How to optimize this javascript code?

- by Andrija

I have a jsp which uses a lot of javascript and it's just not fast enough. I would like to optimize it so first, here's a part of the code: In the jsp I have the initialization: window.onload = function () { formCollection.pageSize.value = "<%= pagingSize%>"; elemCollection = iDom3.Table.all["spis"].XML.DOM; <% if (resultList != null) { %> elementsNumber = <%= resultList.size() %>; <%} else { %> elementsNumber = 0; <% } %> contextPath = "<%= request.getContextPath() %>"; } In my js file I have two types of js functions: // gets the first element and sets it's value to all the other; //the selectSingleNode function is used because I use XSLT transformation //to generate the table _setTehJed = function(){ var resultId = formCollection.elements["idTehJedinice_spis_1"].value; var resultText = formCollection.elements["tehnicka_spis_1"].value; if (resultId != ""){ var counter = 1; while (counter<elementsNumber){ counter++; if(formCollection.elements["idTehJedinice_spis_"+counter] != null){ formCollection.elements["idTehJedinice_spis_"+counter].value=resultId; formCollection.elements["tehnicka_spis_"+counter].value=resultText; } var node=elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'tehnicka']/title"); node.text=resultText; var node2=elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'idTehJedinice']/title"); node2.text=resultId; } } } // sets the elements checkbox to checked or unchecked _SelectCheckRokCuvanja = { all : [], Item : function (oItem, sId) { this.all["spis_"+sId] = oItem.value; if (oItem.checked) { elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "true"); }else{ elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "false"); } } } I've used these tips: http://blogs.msdn.com/b/ie/archive/2006/08/28/728654.aspx http://code.google.com/speed/articles/optimizing-javascript.html but I still think something could be done like defining the functions like this: In the jsp: window.onload = function () { iDom3.DigitalnaArhivaPrihvat.formCollection=document.forms["controller"]; iDom3.DigitalnaArhivaPrihvat.formCollection.pageSize.value = "<%= pagingSize%>"; iDom3.DigitalnaArhivaPrihvat.elemCollection = iDom3.Table.all["spis"].XML.DOM; <% if (resultList != null) { %> iDom3.DigitalnaArhivaPrihvat.elementsNumber = <%= resultList.size() %> <%} else { %> iDom3.DigitalnaArhivaPrihvat.elementsNumber = 0; <% } %> } in the js: iDom3.DigitalnaArhivaPrihvat = { formCollection:null, elemCollection:null, elementsNumber:null, _setTehJed : function(){ var resultId = this.formCollection.elements.idTehJedinice_spis_1.value; var resultText = this.formCollection.elements.tehnicka_spis_1.value; if (resultId != ""){ var counter = 1; while (counter<this.elementsNumber){ counter++; if(this.formCollection.elements["idTehJedinice_spis_"+counter] !== null){ this.formCollection.elements["idTehJedinice_spis_"+counter].value=resultId; this.formCollection.elements["tehnicka_spis_"+counter].value=resultText; } var node=this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'tehnicka']/title"); node.text=resultText; var node2=this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'idTehJedinice']/title"); node2.text=resultId; } } }, _SelectCheckRokCuvanja = { all : [], Item : function (oItem, sId) { this.all["spis_"+sId] = oItem.value; if (oItem.checked) { this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "true"); }else{ this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "false"); } } } but the problem is scoping (if I do it like this, the second function does not execute properly). Any suggestions?

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ComboBox values disappears after selected when objects used for display

- by Gakk

I have a combobox where I want to display objects and have enum values returned. When first opened the combobox displays the items as supposed, but after a value is chosen it seems to disappear from the list. But if the combobox is active I can use the keyboard to navigate up and down between the other values, so they are in the list but only invisible. I have created a little test application to show my problem. When started the application shows the combobox with all the choices (the two first are type of Object, the third is a String): After the blue line is selected and when the combobox is opened again this line is missing: When the line with the text "Green" is selected that line is still showing: If I had chosen the red line the only thing that would still be in the list is the test "Green". I am using .NET Framework 3.5. Any hints or tips to why the elements disappears? Here are all the code needed after starting a blank project in Visual Studio. MainWindow.xaml.cs: using System; using System.Collections.Generic; using System.Diagnostics; namespace Test { public partial class MainWindow { public MainWindow() { InitializeComponent(); } private ColorComboBoxValue _activeColor; public ColorComboBoxValue ActiveColor { get { return _activeColor; } set { _activeColor = value; Debug.WriteLine("ActiveColor: " + _activeColor.Color); } } } public class ColorList : List<ColorComboBoxValue> { } public class ColorComboBoxValue { public Color Color { get; set; } public Object Object { get; set; } } public enum Color { Red, Blue, Green } } MainWindow.xaml: <Window x:Class="Test.MainWindow" x:Name="window" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:System="clr-namespace:System;assembly=mscorlib" xmlns:local="clr-namespace:Test" Title="ComboBoxTest" Height="100" Width="200"> <Window.Resources> <local:ColorList x:Key="ColorList"> <local:ColorComboBoxValue Color="Red"> <local:ColorComboBoxValue.Object> <Path Data="M0,0 L0,30 60,30 60,0 Z" Fill="Red"/> </local:ColorComboBoxValue.Object> </local:ColorComboBoxValue> <local:ColorComboBoxValue Color="Blue"> <local:ColorComboBoxValue.Object> <Path Data="M0,0 L0,30 60,30 60,0 Z" Fill="Blue"/> </local:ColorComboBoxValue.Object> </local:ColorComboBoxValue> <local:ColorComboBoxValue Color="Green"> <local:ColorComboBoxValue.Object> <System:String>Green</System:String> </local:ColorComboBoxValue.Object> </local:ColorComboBoxValue> </local:ColorList> </Window.Resources> <ComboBox ItemsSource="{Binding Source={StaticResource ColorList}}" SelectedItem="{Binding ActiveColor, ElementName=window}"> <ComboBox.ItemTemplate> <DataTemplate> <ContentPresenter Content="{Binding Path=Object}"/> </DataTemplate> </ComboBox.ItemTemplate> </ComboBox> </Window>

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Most secure way to access my home Linux server while I am on the road? Specialized solution wanted

- by Ace Paus

I think many people may be in my situation. I travel on business with a laptop. And I need secure access to files from the office (which in my case is my home). The short version of my question: How can I make SSH/SFTP really secure when only one person needs to connect to the server from one laptop? In this situation, what special steps would make it almost impossible for anyone else to get online access to the server? A lot more details: I use Ubuntu Linux on both my laptop (KDE) and my home/office server. Connectivity is not a problem. I can tether to my phone's connection if needed. I need access to a large number of files (around 300 GB). I don't need all of them at once, but I don't know in advance which files I might need. These files contain confidential client info and personal info such as credit card numbers, so they must be secure. Given this, I don't want store all these files on Dropbox or Amazon AWS, or similar. I couldn't justify that cost anyway (Dropbox don't even publish prices for plans above 100 GB, and security is a concern). However, I am willing to spend some money on a proper solution. A VPN service, for example, might be part of the solution? Or other commercial services? I've heard about PogoPlug, but I don't know if there is a similar service that might address my security concerns? I could copy all my files to my laptop because it has the space. But then I have to sync between my home computer and my laptop and I found in the past that I'm not very good about doing this. And if my laptop is lost or stolen, my data would be on it. The laptop drive is an SSD and encryption solutions for SSD drives are not good. Therefore, it seems best to keep all my data on my Linux file server (which is safe at home). Is that a reasonable conclusion, or is anything connected to the Internet such a risk that I should just copy the data to the laptop (and maybe replace the SSD with an HDD, which reduces battery life and performance)? I view the risks of losing a laptop to be higher. I am not an obvious hacking target online. My home broadband is cable Internet, and it seems very reliable. So I want to know the best (reasonable) way to securely access my data (from my laptop) while on the road. I only need to access it from this one computer, although I may connect from either my phone's 3G/4G or via WiFi or some client's broadband, etc. So I won't know in advance which IP address I'll have. I am leaning toward a solution based on SSH and SFTP (or similar). SSH/SFTP would provided about all the functionality I anticipate needing. I would like to use SFTP and Dolphin to browse and download files. I'll use SSH and the terminal for anything else. My Linux file server is set up with OpenSSH. I think I have SSH relatively secured. I'm using Denyhosts too. But I want to go several steps further. I want to get the chances that anyone can get into my server as close to zero as possible while still allowing me to get access from the road. I'm not a sysadmin or programmer or real "superuser". I have to spend most of my time doing other things. I've heard about "port knocking" but I have never used it and I don't know how to implement it (although I'm willing to learn). I have already read a number of articles with titles such as: Top 20 OpenSSH Server Best Security Practices 20 Linux Server Hardening Security Tips Debian Linux Stop SSH User Hacking / Cracking Attacks with DenyHosts Software more... I have not implemented every single thing I've read about. I probably can't do that. But maybe there is something even better I can do in my situation because I only need access from a single laptop. I'm just one user. My server does not need to be accessible to the general public. Given all these facts, I'm hoping I can get some suggestions here that are within my capability to implement and that leverage these facts to create a great deal better security than general purpose suggestions in the articles above.

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Sencha Touch 2 - Can't get list to display // or load a store? [UPDATED X2]

- by Jordan

I have been trying to get a list to display for quite a while now. I have tried all sorts of tips from various people without success. Now I am running into a new problem. I have taken the exact code from an example and I can't seem to get it to work either. First of all, here is the code. Station.js Ext.define('Syl.model.Station', { extend: 'Ext.data.Model', config: { fields: [ { name: 'id', type: 'string' }, { name: 'stop', type: 'string' } ] } }); Stations.js Ext.define('Syl.store.Stations', { extend : 'Ext.data.Store', requires: ['Syl.model.Station'], id: 'stations', xtype: 'stations', config : { model : 'Syl.model.Station', //storeId: 'stationsStore', autoLoad : true, //sorters: 'stop', /* proxy: { type: 'ajax', url: 'stations.json' }*/ data: [ { "id": "129", "stop": "NY Station" }, { "id": "13", "stop": "Newark Station" } ] } }); MyService.js Ext.define('Syl.view.MyService', { extend: 'Ext.Panel', xtype: 'stationsformPage', requires: [ 'Syl.store.Stations', 'Ext.form.FieldSet', 'Ext.field.Password', 'Ext.SegmentedButton', 'Ext.List' ], config: { fullscreen: true, layout: 'vbox', //iconCls: 'settings', //title: 'My Service', items: [ { docked: 'top', xtype: 'toolbar', title: 'My Service' }, { [OLDER CODE BEGIN] xtype: 'list', title: 'Stations', //store: 'Stations', store: stationStore, //UPDATED styleHtmlContent: true, itemTpl: '<div><strong>{stop}</strong> {id}</div>' [OLDER CODE END] [UPDATE X2 CODE BEGIN] xtype: 'container', layout: 'fit', flex: 10, items: [{ xtype: 'list', title: 'Stations', width: '100%', height: '100%', store: stationStore, styleHtmlContent: true, itemTpl: '<div><strong>{stop}</strong> {id}</div>' }] [UPDATE X2 CODE END] }, ] } }); app.js (edited down to the basics) var stationStore; //UPDATED Ext.application({ name: 'Syl', views: ['MyService'], store: ['Stations'], model: ['Station'], launch: function() { stationStore = Ext.create('Syl.store.Stations');//UPDATED var mainPanel = Ext.Viewport.add(Ext.create('Syl.view.MyService')); }, }); Okay, now when I run this in the browser, I get this error: "[WARN][Ext.dataview.List#applyStore] The specified Store cannot be found". The app runs but there is no list. I can't understand how this code could work for the people who gave the example and not me. Could it be a difference in the Sencha Touch version? I am using 2.0.1.1. To add to this, I have been having problems in general with lists not displaying. I had originally tried a stripped down list without even having a store. I tried to just set the data property in the list's config. I didn't get this error, but I also didn't get a list to display. That is why I thought I would try someone else's code. I figured if I could at least get a working list up and running, I could manipulate it into doing what I want. Any help would be greatly appreciated. Thanks. [UPDATED] Okay, so I did some more hunting and someone told me I needed to have an instance of my store to load into the list, not the store definition. So I updated the code as you can see and the error went away. The problem is that I still don't get a list. I have no errors at all, but I can't see a list. Am I not loading the data correctly? Or am I not putting the list in the view correctly? [UPDATED X2] Okay, so I learned that the list should be in a container and that I should give it a width and a height. I'm not totally sure on this being correct, but I do now have a list that I can drag up and down. The problem is there is still nothing in it. Anyone have a clue why?

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What needs updating when moving a bootable Windows 7 (or Vista) partition?

- by SuperTempel

When I move a bootable NTFS partition with Windows on it to a different block offset, what needs updating to make it bootable again? In particular, here's what I tried: I have a disk with several partitions, one of which is the NTFS partition with Windows on it, and the disk uses the plain old MBR block 0 for the partitions layout (no more than 4 partitions). Now I format and partition a new, larger, disk. There I make room for the NTFS partition and copy the contents from the old disk's NTFS Windows partition into. And I make the partition "active". However, when I try to boot from this disk, I get a "read error" message immediately and the booting stops, the exact text is: A disk read error occurred Press Ctrl+Alt+Del to restart I verified that both disks have the same boot sector code in block 0. It seems to me that something else might need updating. I guess that somewhere there's a absolute block reference that I need to update, probably pointing to the next level loader or to the NT kernel. Update: I found this article going quite into the depth of what I want to know. However, it says to modify boot.ini, but I have Windows 7 installed here, where such things appear to have changed: No boot.ini but a folder called System Volume Information with GUID and other data in it that sounds related to my problem. Going to keep digging... Update 2: Thanks to the terrible looking but very informative website by starman, I was able to figure out the first step: The NTFS boot sector has a field for "hidden" sectors. This feld has to contain the sector number of the boot sector. This solves the "read error" message. Now, however, I get a "BOOTMGR is missing" error instead. Looks like there's another place where a block number has to be adjusted, but I can't find anything in the code listing about this. I do find a lot of help sites suggesting Windows tools for fixing this "BOOTMGR is missing" problem, but none seem to know what goes on behind the scenes. Kind of like suggesting to re-install Windows when there's a little problem with it. At least, those fixes seem to work, mostly involving the Bcdedit and Bootrec tools. Now, who knows what they do, especially the latter, in regards to a moved partition? Update 3: After lots of trial-and-error attempts, I believe now that the solution lies in the BCD-Template registry file, residing usually inside \Windows\System32\config. If I get this updated using the "bcdboot" command, Windows starts up from it. I am now in the middle of figuring out what information this registry contains relevant to the above question. Any pointers to the contents of this registry are welcome. Update 4: Turns out that while the BCD-Template file gets rewritten and has different binary contents than its predecessor, the values inside do not change. So it must be something else that bcdboot.exe writes. I had previously already checked if it changes the first 32 boot blocks of the partition, but they appear to remain unchanged. Parititon map doesn't get changed, either. So what is it that bcdboot modifies besides the BCD registry? Any tips on how I can trace that? Are there low level tools that show me what files a program writes to? Update 5: The answer seems to be: c:\Boot\BCD is also changed, and that appears to be the key file for the boot manager's process. I'll investigate this later... Update 6: It seems to be an important detail that I had originally two partitions created when I installed Windows 7: A small partition of 204800 sectors which appears to be a bootstrap partition, followed by the actual, large, partition containing the Windows system (drive C:). When I tried to transfer this installation to a new, larger, disk, I had kept the same two partitions intact on the new drive, although they ended up at a different offset. This alone led to the "BOOTMGR is missing" message. Since then, I've used bcdboot.exe only on the Windows partition, which added the \Boot\BCD file on that partition. That file (and folder) did originally only exist on the smaller partition. Hence, this problem may be more complicated in my case as one partition (the boot strapper) referred to another partition (the one containing the OS), whereas other people may only have to deal with one partition containing both, and maybe there the solution is simpler. Update 7: Found one more detail: The \Boot\BCD file records the MBR's serial number. If that number doesn't match, the system won't boot. Next I'll test if there's also an absolute block reference stored in there.

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Alphabetically Ordering an array of words

- by Genesis

I'm studying C on my own in preparation for my upcoming semester of school and was wondering what I was doing wrong with my code so far. If Things look weird it is because this is part of a much bigger grab bag of sorting functions I'm creating to get a sense of how to sort numbers,letters,arrays,and the like! I'm basically having some troubles with the manipulation of strings in C currently. Also, I'm quite limited in my knowledge of C at the moment! My main Consists of this: #include <stdio.h> #include <stdio.h> #include <stdlib.h> int numbers[10]; int size; int main(void){ setvbuf(stdout,NULL,_IONBF,0); //This is magical code that allows me to input. int wordNumber; int lengthOfWord = 50; printf("How many words do you want to enter: "); scanf("%i", &wordNumber); printf("%i\n",wordNumber); char words[wordNumber][lengthOfWord]; printf("Enter %i words:",wordNumber); int i; for(i=0;i<wordNumber+1;i++){ //+1 is because my words[0] is blank. fgets(&words[i], 50, stdin); } for(i=1;i<wordNumber+1;i++){ // Same as the above comment! printf("%s", words[i]); //prints my words out! } alphabetize(words,wordNumber); //I want to sort these arrays with this function. } My sorting "method" I am trying to construct is below! This function is seriously flawed, but I'd thought I'd keep it all to show you where my mind was headed when writing this. void alphabetize(char a[][],int size){ // This wont fly. size = size+1; int wordNumber; int lengthOfWord; char sortedWords[wordNumber][lengthOfWord]; //In effort for the for loop int i; int j; for(i=1;i<size;i++){ //My effort to copy over this array for manipulation for(j=1;j<size;j++){ sortedWords[i][j] = a[i][j]; } } //This should be kinda what I want when ordering words alphabetically, right? for(i=1;i<size;i++){ for(j=2;j<size;j++){ if(strcmp(sortedWords[i],sortedWords[j]) > 0){ char* temp = sortedWords[i]; sortedWords[i] = sortedWords[j]; sortedWords[j] = temp; } } } for(i=1;i<size;i++){ printf("%s, ",sortedWords[i]); } } I guess I also have another question as well... When I use fgets() it's doing this thing where I get a null word for the first spot of the array. I have had other issues recently trying to scanf() char[] in certain ways specifically spacing my input word variables which "magically" gets rid of the first null space before the character. An example of this is using scanf() to write "Hello" and getting " Hello" or " ""Hello"... Appreciate any thoughts on this, I've got all summer to study up so this doesn't need to be answered with haste! Also, thank you stack overflow as a whole for being so helpful in the past. This may be my first post, but I have been a frequent visitor for the past couple of years and it's been one of the best places for helpful advice/tips.

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mapping rect in small image to larger image (in order to do a copyPixels operation)

- by skinnyTOD

Hi all - this is (I think) a relatively simple math question but I've spent a day banging my head against it and have only the dents and no solution... I'm coding in actionscript 3 - the functionality is: large image loaded at runtime. The bitmapData is stored and a smaller version is created to display on the available screen area (I may end up just scaling the large image since it is in memory anyway). The user can create a rectangle hotspot on the smaller image (the functionality will be more complex: multiple rects with transparency: example a donut shape with hole, etc) 3 When the user clicks on the hotspot, the rect of the hotspot is mapped to the larger image and a new bitmap "callout" is created, using the larger bitmap data. The reason for this is so the "callout" will be better quality than just scaling up the area of the hotspot. The image below shows where I am at so far- the blue rect is the clicked hotspot. In the upper left is the "callout" - copied from the larger image. I have the aspect ratio right but I am not mapping to the larger image correctly. Ugly code below... Sorry this post is so long - I just figured I ought to provide as much info as possible. Thanks for any tips! --trace of my data values *source BitmapDada 1152 864 scaled to rect 800 600 scaled BitmapData 800 600 selection BitmapData 58 56 scaled selection 83 80 ratio 1.44 before (x=544, y=237, w=58, h=56) (x=544, y=237, w=225.04, h=217.28) * Image here: http://i795.photobucket.com/albums/yy237/skinnyTOD/exampleST.jpg public function onExpandCallout(event:MouseEvent):void{ if (maskBitmapData.getPixel32(event.localX, event.localY) != 0){ var maskClone:BitmapData = maskBitmapData.clone(); //amount to scale callout - this will vary/can be changed by user var scale:Number =150 //scale percentage var normalizedScale :Number = scale/=100; var w:Number = maskBitmapData.width*normalizedScale; var h:Number = maskBitmapData.height*normalizedScale; var ratio:Number = (sourceBD.width /targetRect.width); //creat bmpd of the scaled size to copy source into var scaledBitmapData:BitmapData = new BitmapData(maskBitmapData.width * ratio, maskBitmapData.height * ratio, true, 0xFFFFFFFF); trace("source BitmapDada " + sourceBD.width, sourceBD.height); trace("scaled to rect " + targetRect.width, targetRect.height); trace("scaled BitmapData", bkgnImageSprite.width, bkgnImageSprite.height); trace("selection BitmapData", maskBitmapData.width, maskBitmapData.height); trace("scaled selection", scaledBitmapData.width, scaledBitmapData.height); trace("ratio", ratio); var scaledBitmap:Bitmap = new Bitmap(scaledBitmapData); var scaleW:Number = sourceBD.width / scaledBitmapData.width; var scaleH:Number = sourceBD.height / scaledBitmapData.height; var scaleMatrix:Matrix = new Matrix(); scaleMatrix.scale(ratio,ratio); var sRect:Rectangle = maskSprite.getBounds(bkgnImageSprite); var sR:Rectangle = sRect.clone(); var ss:Sprite = new Sprite(); ss.graphics.lineStyle(8, 0x0000FF); //ss.graphics.beginFill(0x000000, 1); ss.graphics.drawRect(sRect.x, sRect.y, sRect.width, sRect.height); //ss.graphics.endFill(); this.addChild(ss); trace("before " + sRect); w = uint(sRect.width * scaleW); h = uint(sRect.height * scaleH); sRect.inflate(maskBitmapData.width * ratio, maskBitmapData.height * ratio); sRect.offset(maskBitmapData.width * ratio, maskBitmapData.height * ratio); trace(sRect); scaledBitmapData.copyPixels(sourceBD, sRect, new Point()); addChild(scaledBitmap); scaledBitmap.x = offsetPt.x; scaledBitmap.y = offsetPt.y; } }

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Objective-C vs JavaScript loop performance

- by micadelli

I have a PhoneGap mobile application that I need to generate an array of match combinations. In JavaScript side, the code hanged pretty soon when the array of which the combinations are generated from got a bit bigger. So, I thought I'll make a plugin to generate the combinations, passing the array of javascript objects to native side and loop it there. To my surprise the following codes executes in 150 ms (JavaScript) whereas in native side (Objective-C) it takes ~1000 ms. Does anyone know any tips for speeding up those executing times? When players exceeds 10, i.e. the length of the array of teams equals 252 it really gets slow. Those execution times mentioned above are for 10 players / 252 teams. Here's the JavaScript code: for (i = 0; i < GAME.teams.length; i += 1) { for (j = i + 1; j < GAME.teams.length; j += 1) { t1 = GAME.teams[i]; t2 = GAME.teams[j]; if ((t1.mask & t2.mask) === 0) { GAME.matches.push({ Team1: t1, Team2: t2 }); } } } ... and here's the native code: NSArray *teams = [[NSArray alloc] initWithArray: [options objectForKey:@"teams"]]; NSMutableArray *t = [[NSMutableArray alloc] init]; int mask_t1; int mask_t2; for (NSInteger i = 0; i < [teams count]; i++) { for (NSInteger j = i + 1; j < [teams count]; j++) { mask_t1 = [[[teams objectAtIndex:i] objectForKey:@"mask"] intValue]; mask_t2 = [[[teams objectAtIndex:j] objectForKey:@"mask"] intValue]; if ((mask_t1 & mask_t2) == 0) { [t insertObject:[teams objectAtIndex:i] atIndex:0]; [t insertObject:[teams objectAtIndex:j] atIndex:1]; /* NSArray *newCombination = [[NSArray alloc] initWithObjects: [teams objectAtIndex:i], [teams objectAtIndex:j], nil]; */ [combinations addObject:t]; } } } ... the array in question (GAME.teams) looks like this: { count = 2; full = 1; list = ( { index = 0; mask = 1; name = A; score = 0; }, { index = 1; mask = 2; name = B; score = 0; } ); mask = 3; name = A; }, { count = 2; full = 1; list = ( { index = 0; mask = 1; name = A; score = 0; }, { index = 2; mask = 4; name = C; score = 0; } ); mask = 5; name = A; },

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Cloning whole form elements after clicking button

- by FreshPro

I have this following form <form action="" class="form-horizontal"> <div id="wrapper"> <div class="row-fluid"> <div class="span6"> <div class="control-group"> <label class="control-label"><?=$core->l("default_comm_type");?></label> <div class="controls"> <select id="fld_default_comm_type" name="fld_default_comm_type[]" defaultValue="-1" class="m-wrap span10" field="fld_default_comm_type" appEditor="true"> <?=combo_creator::render_default_comm_types()?> </select> </div> </div> </div> <div class="span4 checkerAlign"> <div class="control-group"> <div class="controls"> <?=$core->l("is_active");?> </div> </div> </div> <div class="span2 checkerAlign"><input type="checkbox" name="fld_active[]" id="fld_active" editType="booleanEdit" appEditor="true"/></div> </div> <div><a href="#" id="addMore">Add Row</a></div> </div> The question is when user clicks Add Row button, I need to create a copy of this form elements inside <div id="wrapper"> How can i do that? EDIT: SOLVED <form action="" class="form-horizontal" id="wrapper"> <div class="row-fluid"> <div class="span6"> <div class="control-group"> <label class="control-label"><?=$core->l("default_comm_type");?></label> <div class="controls"> <select id="fld_default_comm_type" name="fld_default_comm_type[]" defaultValue="-1" class="m-wrap span10" field="fld_default_comm_type" appEditor="true"> <?=combo_creator::render_default_comm_types()?> </select> </div> </div> </div> <div class="span4 checkerAlign"> <div class="control-group"> <div class="controls"> <?=$core->l("is_active");?> </div> </div> </div> <div class="span2 checkerAlign"><input type="checkbox" name="fld_active[]" id="fld_active" editType="booleanEdit" appEditor="true"/></div> </div> <a href="#" data-action="add">add</a> <a href="#" data-action="delete">delete</a> </form> In the Js part: jQuery("#addMore").click(function(){ var contents = jQuery("form").html(); jQuery("#test").append(contents); }); When add is clicked it inserts form elements just as I wanted and when delete is clicked it deletes elements. Thank you for the tips guys Problem solved! Thanks guys.

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Inheritance Mapping Strategies with Entity Framework Code First CTP5 Part 1: Table per Hierarchy (TPH)

- by mortezam

A simple strategy for mapping classes to database tables might be “one table for every entity persistent class.” This approach sounds simple enough and, indeed, works well until we encounter inheritance. Inheritance is such a visible structural mismatch between the object-oriented and relational worlds because object-oriented systems model both “is a” and “has a” relationships. SQL-based models provide only "has a" relationships between entities; SQL database management systems don’t support type inheritance—and even when it’s available, it’s usually proprietary or incomplete. There are three different approaches to representing an inheritance hierarchy: Table per Hierarchy (TPH): Enable polymorphism by denormalizing the SQL schema, and utilize a type discriminator column that holds type information. Table per Type (TPT): Represent "is a" (inheritance) relationships as "has a" (foreign key) relationships. Table per Concrete class (TPC): Discard polymorphism and inheritance relationships completely from the SQL schema.I will explain each of these strategies in a series of posts and this one is dedicated to TPH. In this series we'll deeply dig into each of these strategies and will learn about "why" to choose them as well as "how" to implement them. Hopefully it will give you a better idea about which strategy to choose in a particular scenario. Inheritance Mapping with Entity Framework Code FirstAll of the inheritance mapping strategies that we discuss in this series will be implemented by EF Code First CTP5. The CTP5 build of the new EF Code First library has been released by ADO.NET team earlier this month. EF Code-First enables a pretty powerful code-centric development workflow for working with data. I’m a big fan of the EF Code First approach, and I’m pretty excited about a lot of productivity and power that it brings. When it comes to inheritance mapping, not only Code First fully supports all the strategies but also gives you ultimate flexibility to work with domain models that involves inheritance. The fluent API for inheritance mapping in CTP5 has been improved a lot and now it's more intuitive and concise in compare to CTP4. A Note For Those Who Follow Other Entity Framework ApproachesIf you are following EF's "Database First" or "Model First" approaches, I still recommend to read this series since although the implementation is Code First specific but the explanations around each of the strategies is perfectly applied to all approaches be it Code First or others. A Note For Those Who are New to Entity Framework and Code-FirstIf you choose to learn EF you've chosen well. If you choose to learn EF with Code First you've done even better. To get started, you can find a great walkthrough by Scott Guthrie here and another one by ADO.NET team here. In this post, I assume you already setup your machine to do Code First development and also that you are familiar with Code First fundamentals and basic concepts. You might also want to check out my other posts on EF Code First like Complex Types and Shared Primary Key Associations. A Top Down Development ScenarioThese posts take a top-down approach; it assumes that you’re starting with a domain model and trying to derive a new SQL schema. Therefore, we start with an existing domain model, implement it in C# and then let Code First create the database schema for us. However, the mapping strategies described are just as relevant if you’re working bottom up, starting with existing database tables. I’ll show some tricks along the way that help you dealing with nonperfect table layouts. Let’s start with the mapping of entity inheritance. -- The Domain ModelIn our domain model, we have a BillingDetail base class which is abstract (note the italic font on the UML class diagram below). We do allow various billing types and represent them as subclasses of BillingDetail class. As for now, we support CreditCard and BankAccount: Implement the Object Model with Code First As always, we start with the POCO classes. Note that in our DbContext, I only define one DbSet for the base class which is BillingDetail. Code First will find the other classes in the hierarchy based on Reachability Convention. public abstract class BillingDetail { public int BillingDetailId { get; set; } public string Owner { get; set; } public string Number { get; set; } } public class BankAccount : BillingDetail { public string BankName { get; set; } public string Swift { get; set; } } public class CreditCard : BillingDetail { public int CardType { get; set; } public string ExpiryMonth { get; set; } public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext { public DbSet<BillingDetail> BillingDetails { get; set; } } This object model is all that is needed to enable inheritance with Code First. If you put this in your application you would be able to immediately start working with the database and do CRUD operations. Before going into details about how EF Code First maps this object model to the database, we need to learn about one of the core concepts of inheritance mapping: polymorphic and non-polymorphic queries. Polymorphic Queries LINQ to Entities and EntitySQL, as object-oriented query languages, both support polymorphic queries—that is, queries for instances of a class and all instances of its subclasses, respectively. For example, consider the following query: IQueryable<BillingDetail> linqQuery = from b in context.BillingDetails select b; List<BillingDetail> billingDetails = linqQuery.ToList(); Or the same query in EntitySQL: string eSqlQuery = @"SELECT VAlUE b FROM BillingDetails AS b"; ObjectQuery<BillingDetail> objectQuery = ((IObjectContextAdapter)context).ObjectContext .CreateQuery<BillingDetail>(eSqlQuery); List<BillingDetail> billingDetails = objectQuery.ToList(); linqQuery and eSqlQuery are both polymorphic and return a list of objects of the type BillingDetail, which is an abstract class but the actual concrete objects in the list are of the subtypes of BillingDetail: CreditCard and BankAccount. Non-polymorphic QueriesAll LINQ to Entities and EntitySQL queries are polymorphic which return not only instances of the specific entity class to which it refers, but all subclasses of that class as well. On the other hand, Non-polymorphic queries are queries whose polymorphism is restricted and only returns instances of a particular subclass. In LINQ to Entities, this can be specified by using OfType<T>() Method. For example, the following query returns only instances of BankAccount: IQueryable<BankAccount> query = from b in context.BillingDetails.OfType<BankAccount>() select b; EntitySQL has OFTYPE operator that does the same thing: string eSqlQuery = @"SELECT VAlUE b FROM OFTYPE(BillingDetails, Model.BankAccount) AS b"; In fact, the above query with OFTYPE operator is a short form of the following query expression that uses TREAT and IS OF operators: string eSqlQuery = @"SELECT VAlUE TREAT(b as Model.BankAccount) FROM BillingDetails AS b WHERE b IS OF(Model.BankAccount)"; (Note that in the above query, Model.BankAccount is the fully qualified name for BankAccount class. You need to change "Model" with your own namespace name.) Table per Class Hierarchy (TPH)An entire class hierarchy can be mapped to a single table. This table includes columns for all properties of all classes in the hierarchy. The concrete subclass represented by a particular row is identified by the value of a type discriminator column. You don’t have to do anything special in Code First to enable TPH. It's the default inheritance mapping strategy: This mapping strategy is a winner in terms of both performance and simplicity. It’s the best-performing way to represent polymorphism—both polymorphic and nonpolymorphic queries perform well—and it’s even easy to implement by hand. Ad-hoc reporting is possible without complex joins or unions. Schema evolution is straightforward. Discriminator Column As you can see in the DB schema above, Code First has to add a special column to distinguish between persistent classes: the discriminator. This isn’t a property of the persistent class in our object model; it’s used internally by EF Code First. By default, the column name is "Discriminator", and its type is string. The values defaults to the persistent class names —in this case, “BankAccount” or “CreditCard”. EF Code First automatically sets and retrieves the discriminator values. TPH Requires Properties in SubClasses to be Nullable in the Database TPH has one major problem: Columns for properties declared by subclasses will be nullable in the database. For example, Code First created an (INT, NULL) column to map CardType property in CreditCard class. However, in a typical mapping scenario, Code First always creates an (INT, NOT NULL) column in the database for an int property in persistent class. But in this case, since BankAccount instance won’t have a CardType property, the CardType field must be NULL for that row so Code First creates an (INT, NULL) instead. If your subclasses each define several non-nullable properties, the loss of NOT NULL constraints may be a serious problem from the point of view of data integrity. TPH Violates the Third Normal FormAnother important issue is normalization. We’ve created functional dependencies between nonkey columns, violating the third normal form. Basically, the value of Discriminator column determines the corresponding values of the columns that belong to the subclasses (e.g. BankName) but Discriminator is not part of the primary key for the table. As always, denormalization for performance can be misleading, because it sacrifices long-term stability, maintainability, and the integrity of data for immediate gains that may be also achieved by proper optimization of the SQL execution plans (in other words, ask your DBA). Generated SQL QueryLet's take a look at the SQL statements that EF Code First sends to the database when we write queries in LINQ to Entities or EntitySQL. For example, the polymorphic query for BillingDetails that you saw, generates the following SQL statement: SELECT [Extent1].[Discriminator] AS [Discriminator], [Extent1].[BillingDetailId] AS [BillingDetailId], [Extent1].[Owner] AS [Owner], [Extent1].[Number] AS [Number], [Extent1].[BankName] AS [BankName], [Extent1].[Swift] AS [Swift], [Extent1].[CardType] AS [CardType], [Extent1].[ExpiryMonth] AS [ExpiryMonth], [Extent1].[ExpiryYear] AS [ExpiryYear] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] IN ('BankAccount','CreditCard') Or the non-polymorphic query for the BankAccount subclass generates this SQL statement: SELECT [Extent1].[BillingDetailId] AS [BillingDetailId], [Extent1].[Owner] AS [Owner], [Extent1].[Number] AS [Number], [Extent1].[BankName] AS [BankName], [Extent1].[Swift] AS [Swift] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] = 'BankAccount' Note how Code First adds a restriction on the discriminator column and also how it only selects those columns that belong to BankAccount entity. Change Discriminator Column Data Type and Values With Fluent API Sometimes, especially in legacy schemas, you need to override the conventions for the discriminator column so that Code First can work with the schema. The following fluent API code will change the discriminator column name to "BillingDetailType" and the values to "BA" and "CC" for BankAccount and CreditCard respectively: protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) { modelBuilder.Entity<BillingDetail>() .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue("BA")) .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue("CC")); } Also, changing the data type of discriminator column is interesting. In the above code, we passed strings to HasValue method but this method has been defined to accepts a type of object: public void HasValue(object value); Therefore, if for example we pass a value of type int to it then Code First not only use our desired values (i.e. 1 & 2) in the discriminator column but also changes the column type to be (INT, NOT NULL): modelBuilder.Entity<BillingDetail>() .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue(1)) .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue(2)); SummaryIn this post we learned about Table per Hierarchy as the default mapping strategy in Code First. The disadvantages of the TPH strategy may be too serious for your design—after all, denormalized schemas can become a major burden in the long run. Your DBA may not like it at all. In the next post, we will learn about Table per Type (TPT) strategy that doesn’t expose you to this problem. References ADO.NET team blog Java Persistence with Hibernate book a { text-decoration: none; } a:visited { color: Blue; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } p.MsoNormal { margin-top: 0in; margin-right: 0in; margin-bottom: 10.0pt; margin-left: 0in; line-height: 115%; font-size: 11.0pt; font-family: "Calibri" , "sans-serif"; }

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Silverlight 4 Training Kit

- by ScottGu

We recently released a new free Silverlight 4 Training Kit that walks you through building business applications with Silverlight 4. You can browse the training kit online or alternatively download an entire offline version of the training kit. The training material is structured on teaching how to use the new Silverlight 4 features to build an end to end business application. The training kit includes 8 modules, 25 videos, and several hands on labs. Below is a breakdown and links to all of the content. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Module 1: Introduction Click here to watch this module. In this video John Papa and Ian Griffiths discuss the key areas that the Building Business Applications with Silverlight 4 course focuses on. This module is the overview of the course and covers many key scenarios that are faced when building business applications, and how Silverlight can help address them. Module 2: WCF RIA Services Click here to explore this module. In this lab, you will create a web site for managing conferences that will be the basis for the other labs in this course. Don’t worry if you don’t complete a particular lab in the series – all lab manual instructions are accompanied by completed solutions, so you can either build your own solution from start to finish, or dive straight in at any point using the solutions provided as a starting point. In this lab you will learn how to set up WCF RIA Services, create bindings to the domain context, filter using the domain data source, and create domain service queries. Online Link Download Source Download Lab Document Videos Module 2.1 - WCF RIA Services Ian Griffiths sets up the Entity Framework and WCF RIA Services for the sample Event Manager application for the course. He covers how to set up the services, how the Domain Services work and the role that the DomainContext plays in the sample application. He also reviews the metadata classes and integrating the navigation framework. Module 2.2 – Using WCF RIA Services to Edit Entities Ian Griffiths discusses how he adds the ability to edit and create individual entities with the features built into WCF RIA Services into the sample Event Manager application. He covers data binding fundamentals, IQueryable, LINQ, the DomainDataSource, navigation to a single entity using the navigation framework, and how to use the Visual Studio designer to do much of the work . Module 2.3 – Showing Master/Details Records Using WCF RIA Services Ian Griffiths reviews how to display master/detail records for the sample Event Manager application using WCF RIA Services. He covers how to use the Include attribute to indicate which elements to serialize back to the client. Ian also demonstrates how to use the Data Sources window in the designer to add and bind controls to specific data elements. He wraps up by showing how to create custom services to the Domain Services. Module 3 – Authentication, Validation, MVVM, Commands, Implicit Styles and RichTextBox Click here to visit this module. This lab demonstrates how to build a login screen, integrate ASP.NET authentication, and perform validation on data elements. Model-View-ViewModel (MVVM) is introduced and used in this lab as a pattern to help separate the UI and business logic. You will also learn how to use implicit styling and the new RichTextBox control. Online Link Download Source Download Lab Document Videos Module 3.1 – Authentication Ian Griffiths covers how to integrate a login screen and authentication into the sample Event Manager application. Ian shows how to use the ASP.NET authentication and integrate it into WCF RIA Services and the Silverlight presentation layer. Module 3.2 – MVVM Ian Griffiths covers how to Model-View-ViewModel (MVVM) patterns into the sample Event Manager application. He discusses why MVVM exists, what separated presentation means, and why it is important. He shows how to connect the View to the ViewModel, why data binding is important in this symbiosis, and how everything fits together in the overall application. Module 3.3 –Validation Ian Griffiths discusses how validation of user input can be integrated into the sample Event Manager application. He demonstrates how to use the DataAnnotations, the INotifyDataErrorInfo interface, binding markup extensions, and WCF RIA Services in concert to achieve great validation in the sample application. He discusses how this technique allows for property level validation, entity level validation, and asynchronous server side validation. Module 3.4 – Implicit Styles Ian Griffiths discusses how why implicit styles are important and how they can be integrated into the sample Event Manager application. He shows how implicit styles defined in a resource dictionary can be applied to all elements of a particular kind throughout the application. Module 3.5 – RichTextBox Ian Griffiths discusses how the new RichTextBox control and it can be integrated into the sample Event Manager application. He demonstrates how the RichTextBox can provide editing for the event information and how it can display the rich text for selection and copying. Module 4 – User Profiles, Drop Targets, Webcam and Clipboard Click here to visit this module. This lab builds new features into the sample application to take the user's photo. It teaches you how to use the webcam to capture an image, use Silverlight as a drop target, and take advantage of programmatic access to the clipboard. Link Download Source Download Lab Document Videos Module 4.1 – Webcam Ian Griffiths demonstrates how the webcam adds value to the sample Event Manager application by capturing an image of the attendee. He discusses the VideoCaptureDevice, the CaptureDviceConfiguration, and the CaptureSource classes and how they allow audio and video to be captured so you can grab an image from the capture device and save it. Module 4.2 - Drag and Drop in Silverlight Ian Griffiths demonstrates how to capture and handle the Drop in the sample Event Manager application so the user can drag a photo from a file and drop it into the application. Ian reviews the AllowDrop property, the Drop event, how to access the file that can be dropped, and the other drag related events. He also reviews how to make this work across browsers and the challenges for this. Module 5 – Schedule Planner and Right Mouse Click Click here to visit this module. This lab builds on the application to allow grouping in the DataGrid and implement right mouse click features to add context menu support. Link Download Source Download Lab Document Videos Module 5.1 – Grouping and Binding Ian Griffiths demonstrates how to use the grouping features for data binding in the DataGrid and how it applies to the sample Event Manager application. He reviews the role of the CollectionViewSource in grouping, customizing the templates for headers, and how to work with grouping with ItemsControls. Module 5.2 – Layout Visual States Ian Griffiths demonstrates how to use the Fluid UI animation support for visual states in the ListBox control DataGrid and how it applies to the sample Event Manager application. He reviews the 3 visual states of BeforeLoaded, AfterLoaded, and BeforeUnloaded. Module 5.3 – Right Mouse Click Ian Griffiths demonstrates how to add support for handling the right mouse button click event to display a context menu for the Event Manager application. He demonstrates how to handle the event, show a custom context menu control, and integrate it into the scheduling portion of the application. Module 6 – Printing the Schedule Click here to visit this module. This lab teaches how to use the new printing features in Silverlight 4. The lab walks through the PrintDocument class and the ViewBox control, while showing how to print multiple pages of content using them. Link Download Source Download Lab Document Videos Module 6.1 – Printing and the Viewbox Ian Griffiths demonstrates how to add the ability to print the schedule to the sample Event Manager application. He walks through the importance of the PrintDocument class and its members. He also shows how to handle printing the visual tree and how the ViewBox control can help. Module 6.2 – Multi Page Printing Ian Griffiths expands on his printing discussion by showing how to handle printing multiple pages of content for the sample Event Manager application. He shows how to paginate the content and points out various tips to keep in mind when determining the printable area. Module 7 – Running the Event Dashboard Out of Browser Click here to visit this module. This lab builds a dashboard for the sample application while explaining the fundamentals of the out of browser features, how to handle authentication, displaying notifications (toasts), and how to use native integration to use COM Interop with Silverlight. Link Download Source Download Lab Document Videos Module 7.1 – Out of Browser Ian Griffiths discusses the role of an Out of Browser application for administrators to manage the events and users in the sample Event Manager application. He discusses several reasons why out of browser applications may better suit your needs including custom chrome, toasts, window placement, cross domain access, and file access. He demonstrates the basic technique to take your application and make it work out of browser using the tools. Module 7.2 – NotificationWindow (Toasts) for Elevated Trust Out of Browser Applications Ian Griffiths discusses the how toasts can be used in the sample Event Manager application to show information that may require the user's attention. Ian covers how to create a toast using the NotificationWindow, security implications, and how to make the toast appear as needed. Module 7.3 – Out of Browser Window Placement Ian Griffiths discusses the how to manage the window positioning when building an out of browser application, handling the windows state, and controlling and handling activation of the window. Module 7.4 – Out of Browser Elevated Trust Application Overview Ian Griffiths discusses the implications of creating trusted out of browser application for the Event Manager sample application. He reviews why you might want to use elevated trust, what features is opens to you, and how to take advantage of them. Topics Ian covers include the dynamic keyword in C# 4, the AutomationFactory class, the API to check if you are in a trusted application, and communicating with Excel. Module 8 – Advanced Out of Browser and MEF Click here to visit this module. This hands-on lab walks through the creation of a trusted out of browser application and the new functionality that comes with that. You will learn to use COM Automation, handle the window closing event, set custom window chrome, digitally sign your Silverlight out of browser trusted application, create a silent install option, and take advantage of MEF. Link Download Source Download Lab Document Videos Module 8.1 – Custom Window Chrome for Elevated Trust Out of Browser Applications Ian Griffiths discusses how to replace the standard operating system window chrome with customized chrome for an elevated trusted out of browser application. He covers how it is important to handle close, resize, minimize, and maximize events. Ian mentions that the tooling was not ready when he shot this video, but the good news is that the tooling now supports setting the custom chrome directly from the property page for the Silverlight application. Module 8.2 – Window Closing Event for Out of Browser Applications Ian Griffiths discusses the WindowClosing event and how to handle and optionally cancel the event. Module 8.3 – Silent Install of Out of Browser Applications Ian Griffiths discusses how to use the SLLauncher executable to install an out of browser application. He discusses the optional command line switches that can be set including how the emulate switch can help you emulate the install process. Ian also shows how to setup a shortcut for the application and tell the application where it should look for future updates online. Module 8.4 – Digitally Signing Out of Browser Application Ian Griffiths discusses how and why to digitally sign an out of browser application using the signtool program. He covers what trusted certificates are, the implications of signing (or not signing), and the effect on the user experience. Module 8.5 – The Value of MEF with Silverlight Ian Griffiths discusses what MEF is, how your application can benefit from it, and the fundamental features it puts at your disposal. He covers the 3 step import, export and compose process as well as how to dynamically import XAP files using MEF. Summary As you can probably tell from the long list above – this series contains a ton of great content, and hopefully provides a nice end-to-end walkthrough that helps explain how to take advantage of Silverlight 4 (and all its new features). Hope this helps, Scott

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Pluralsight Meet the Author Podcast on Structuring JavaScript Code

- by dwahlin

I had the opportunity to talk with Fritz Onion from Pluralsight about one of my recent courses titled Structuring JavaScript Code for one of their Meet the Author podcasts. We talked about why JavaScript patterns are important for building more re-useable and maintainable apps, pros and cons of different patterns, and how to go about picking a pattern as a project is started. The course provides a solid walk-through of converting what I call “Function Spaghetti Code” into more modular code that’s easier to maintain, more re-useable, and less susceptible to naming conflicts. Patterns covered in the course include the Prototype Pattern, Revealing Module Pattern, and Revealing Prototype Pattern along with several other tips and techniques that can be used. Meet the Author: Dan Wahlin on Structuring JavaScript Code The transcript from the podcast is shown below: [Fritz] Hello, this is Fritz Onion with another Pluralsight author interview. Today we’re talking with Dan Wahlin about his new course, Structuring JavaScript Code. Hi, Dan, it’s good to have you with us today. [Dan] Thanks for having me, Fritz. [Fritz] So, Dan, your new course, which came out in December of 2011 called Structuring JavaScript Code, goes into several patterns of usage in JavaScript as well as ways of organizing your code and what struck me about it was all the different techniques you described for encapsulating your code. I was wondering if you could give us just a little insight into what your motivation was for creating this course and sort of why you decided to write it and record it. [Dan] Sure. So, I got started with JavaScript back in the mid 90s. In fact, back in the days when browsers that most people haven’t heard of were out and we had JavaScript but it wasn’t great. I was on a project in the late 90s that was heavy, heavy JavaScript and we pretty much did what I call in the course function spaghetti code where you just have function after function, there’s no rhyme or reason to how those functions are structured, they just kind of flow and it’s a little bit hard to do maintenance on it, you really don’t get a lot of reuse as far as from an object perspective. And so coming from an object-oriented background in JAVA and C#, I wanted to put something together that highlighted kind of the new way if you will of writing JavaScript because most people start out just writing functions and there’s nothing with that, it works, but it’s definitely not a real reusable solution. So the course is really all about how to move from just kind of function after function after function to the world of more encapsulated code and more reusable and hopefully better maintenance in the process. [Fritz] So I am sure a lot of people have had similar experiences with their JavaScript code and will be looking forward to seeing what types of patterns you’ve put forth. Now, a couple I noticed in your course one is you start off with the prototype pattern. Do you want to describe sort of what problem that solves and how you go about using it within JavaScript? [Dan] Sure. So, the patterns that are covered such as the prototype pattern and the revealing module pattern just as two examples, you know, show these kind of three things that I harp on throughout the course of encapsulation, better maintenance, reuse, those types of things. The prototype pattern specifically though has a couple kind of pros over some of the other patterns and that is the ability to extend your code without touching source code and what I mean by that is let’s say you’re writing a library that you know either other teammates or other people just out there on the Internet in general are going to be using. With the prototype pattern, you can actually write your code in such a way that we’re leveraging the JavaScript property and by doing that now you can extend my code that I wrote without touching my source code script or you can even override my code and perform some new functionality. Again, without touching my code. And so you get kind of the benefit of the almost like inheritance or overriding in object oriented languages with this prototype pattern and it makes it kind of attractive that way definitely from a maintenance standpoint because, you know, you don’t want to modify a script I wrote because I might roll out version 2 and now you’d have to track where you change things and it gets a little tricky. So with this you just override those pieces or extend them and get that functionality and that’s kind of some of the benefits that that pattern offers out of the box. [Fritz] And then the revealing module pattern, how does that differ from the prototype pattern and what problem does that solve differently? [Dan] Yeah, so the prototype pattern and there’s another one that’s kind of really closely lined with revealing module pattern called the revealing prototype pattern and it also uses the prototype key word but it’s very similar to the one you just asked about the revealing module pattern. [Fritz] Okay. [Dan] This is a really popular one out there. In fact, we did a project for Microsoft that was very, very heavy JavaScript. It was an HMTL5 jQuery type app and we use this pattern for most of the structure if you will for the JavaScript code and what it does in a nutshell is allows you to get that encapsulation so you have really a single function wrapper that wraps all your other child functions but it gives you the ability to do public versus private members and this is kind of a sort of debate out there on the web. Some people feel that all JavaScript code should just be directly accessible and others kind of like to be able to hide their, truly their private stuff and a lot of people do that. You just put an underscore in front of your field or your variable name or your function name and that kind of is the defacto way to say hey, this is private. With the revealing module pattern you can do the equivalent of what objective oriented languages do and actually have private members that you literally can’t get to as an external consumer of the JavaScript code and then you can expose only those members that you want to be public. Now, you don’t get the benefit though of the prototype feature, which is I can’t easily extend the revealing module pattern type code if you don’t like something I’m doing, chances are you’re probably going to have to tweak my code to fix that because we’re not leveraging prototyping but in situations where you’re writing apps that are very specific to a given target app, you know, it’s not a library, it’s not going to be used in other apps all over the place, it’s a pattern I actually like a lot, it’s very simple to get going and then if you do like that public/private feature, it’s available to you. [Fritz] Yeah, that’s interesting. So it’s almost, you can either go private by convention just by using a standard naming convention or you can actually enforce it by using the prototype pattern. [Dan] Yeah, that’s exactly right. [Fritz] So one of the things that I know I run across in JavaScript and I’m curious to get your take on is we do have all these different techniques of encapsulation and each one is really quite different when you’re using closures versus simply, you know, referencing member variables and adding them to your objects that the syntax changes with each pattern and the usage changes. So what would you recommend for people starting out in a brand new JavaScript project? Should they all sort of decide beforehand on what patterns they’re going to stick to or do you change it based on what part of the library you’re working on? I know that’s one of the points of confusion in this space. [Dan] Yeah, it’s a great question. In fact, I just had a company ask me about that. So which one do I pick and, of course, there’s not one answer fits all. [Fritz] Right. [Dan] So it really depends what you just said is absolutely in my opinion correct, which is I think as a, especially if you’re on a team or even if you’re just an individual a team of one, you should go through and pick out which pattern for this particular project you think is best. Now if it were me, here’s kind of the way I think of it. If I were writing a let’s say base library that several web apps are going to use or even one, but I know that there’s going to be some pieces that I’m not really sure on right now as I’m writing I and I know people might want to hook in that and have some better extension points, then I would look at either the prototype pattern or the revealing prototype. Now, really just a real quick summation between the two the revealing prototype also gives you that public/private stuff like the revealing module pattern does whereas the prototype pattern does not but both of the prototype patterns do give you the benefit of that extension or that hook capability. So, if I were writing a library that I need people to override things or I’m not even sure what I need them to override, I want them to have that option, I’d probably pick a prototype, one of the prototype patterns. If I’m writing some code that is very unique to the app and it’s kind of a one off for this app which is what I think a lot of people are kind of in that mode as writing custom apps for customers, then my personal preference is the revealing module pattern you could always go with the module pattern as well which is very close but I think the revealing module patterns a little bit cleaner and we go through that in the course and explain kind of the syntax there and the differences. [Fritz] Great, that makes a lot of sense. [Fritz] I appreciate you taking the time, Dan, and I hope everyone takes a chance to look at your course and sort of make these decisions for themselves in their next JavaScript project. Dan’s course is, Structuring JavaScript Code and it’s available now in the Pluralsight Library. So, thank you very much, Dan. [Dan] Thanks for having me again.

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10 Essential Tools for building ASP.NET Websites

- by Stephen Walther

I recently put together a simple public website created with ASP.NET for my company at Superexpert.com. I was surprised by the number of free tools that I ended up using to put together the website. Therefore, I thought it would be interesting to create a list of essential tools for building ASP.NET websites. These tools work equally well with both ASP.NET Web Forms and ASP.NET MVC. Performance Tools After reading Steve Souders two (very excellent) books on front-end website performance High Performance Web Sites and Even Faster Web Sites, I have been super sensitive to front-end website performance. According to Souders’ Performance Golden Rule: “Optimize front-end performance first, that's where 80% or more of the end-user response time is spent” You can use the tools below to reduce the size of the images, JavaScript files, and CSS files used by an ASP.NET application. 1. Sprite and Image Optimization Framework CSS sprites were first described in an article written for A List Apart entitled CSS sprites: Image Slicing’s Kiss of Death. When you use sprites, you combine multiple images used by a website into a single image. Next, you use CSS trickery to display particular sub-images from the combined image in a webpage. The primary advantage of sprites is that they reduce the number of requests required to display a webpage. Requesting a single large image is faster than requesting multiple small images. In general, the more resources – images, JavaScript files, CSS files – that must be moved across the wire, the slower your website. However, most people avoid using sprites because they require a lot of work. You need to combine all of the images and write just the right CSS rules to display the sub-images. The Microsoft Sprite and Image Optimization Framework enables you to avoid all of this work. The framework combines the images for you automatically. Furthermore, the framework includes an ASP.NET Web Forms control and an ASP.NET MVC helper that makes it easy to display the sub-images. You can download the Sprite and Image Optimization Framework from CodePlex at http://aspnet.codeplex.com/releases/view/50869. The Sprite and Image Optimization Framework was written by Morgan McClean who worked in the office next to mine at Microsoft. Morgan was a scary smart Intern from Canada and we discussed the Framework while he was building it (I was really excited to learn that he was working on it). Morgan added some great advanced features to this framework. For example, the Sprite and Image Optimization Framework supports something called image inlining. When you use image inlining, the actual image is stored in the CSS file. Here’s an example of what image inlining looks like: .Home_StephenWalther_small-jpg { width:75px; height:100px; background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEsAAABkCAIAAABB1lpeAAAAB GdBTUEAALGOfPtRkwAAACBjSFJNAACHDwAAjA8AAP1SAACBQAAAfXkAAOmLAAA85QAAGcxzPIV3AAAKL s+zNfREAAAAASUVORK5CYII=) no-repeat 0% 0%; } The actual image (in this case a picture of me that is displayed on the home page of the Superexpert.com website) is stored in the CSS file. If you visit the Superexpert.com website then very few separate images are downloaded. For example, all of the images with a red border in the screenshot below take advantage of CSS sprites: Unfortunately, there are some significant Gotchas that you need to be aware of when using the Sprite and Image Optimization Framework. There are workarounds for these Gotchas. I plan to write about these Gotchas and workarounds in a future blog entry. 2. Microsoft Ajax Minifier Whenever possible you should combine, minify, compress, and cache with a far future header all of your JavaScript and CSS files. The Microsoft Ajax Minifier makes it easy to minify JavaScript and CSS files. Don’t confuse minification and compression. You need to do both. According to Souders, you can reduce the size of a JavaScript file by an additional 20% (on average) by minifying a JavaScript file after you compress the file. When you minify a JavaScript or CSS file, you use various tricks to reduce the size of the file before you compress the file. For example, you can minify a JavaScript file by replacing long JavaScript variables names with short variables names and removing unnecessary white space and comments. You can minify a CSS file by doing such things as replacing long color names such as #ffffff with shorter equivalents such as #fff. The Microsoft Ajax Minifier was created by Microsoft employee Ron Logan. Internally, this tool was being used by several large Microsoft websites. We also used the tool heavily on the ASP.NET team. I convinced Ron to publish the tool on CodePlex so that everyone in the world could take advantage of it. You can download the tool from the ASP.NET Ajax website and read documentation for the tool here. I created the installer for the Microsoft Ajax Minifier. When creating the installer, I also created a Visual Studio build task to make it easy to minify all of your JavaScript and CSS files whenever you do a build within Visual Studio automatically. Read the Ajax Minifier Quick Start to learn how to configure the build task. 3. ySlow The ySlow tool is a free add-on for Firefox created by Yahoo that enables you to test the front-end of your website. For example, here are the current test results for the Superexpert.com website: The Superexpert.com website has an overall score of B (not perfect but not bad). The ySlow tool is not perfect. For example, the Superexpert.com website received a failing grade of F for not using a Content Delivery Network even though the website using the Microsoft Ajax Content Delivery Network for JavaScript files such as jQuery. Uptime After publishing a website live to the world, you want to ensure that the website does not encounter any issues and that it stays live. I use the following tools to monitor the Superexpert.com website now that it is live. 4. ELMAH ELMAH stands for Error Logging Modules and Handlers for ASP.NET. ELMAH enables you to record any errors that happen at your website so you can review them in the future. You can download ELMAH for free from the ELMAH project website. ELMAH works great with both ASP.NET Web Forms and ASP.NET MVC. You can configure ELMAH to store errors in a number of different stores including XML files, the Event Log, an Access database, a SQL database, an Oracle database, or in computer RAM. You also can configure ELMAH to email error messages to you when they happen. By default, you can access ELMAH by requesting the elmah.axd page from a website with ELMAH installed. Here’s what the elmah page looks like from the Superexpert.com website (this page is password-protected because secret information can be revealed in an error message): If you click on a particular error message, you can view the original Yellow Screen ASP.NET error message (even when the error message was never displayed to the actual user). I installed ELMAH by taking advantage of the new package manager for ASP.NET named NuGet (originally named NuPack). You can read the details about NuGet in the following blog entry by Scott Guthrie. You can download NuGet from CodePlex. 5. Pingdom I use Pingdom to verify that the Superexpert.com website is always up. You can sign up for Pingdom by visiting Pingdom.com. You can use Pingdom to monitor a single website for free. At the Pingdom website, you configure the frequency that your website gets pinged. I verify that the Superexpert.com website is up every 5 minutes. I have the Pingdom service verify that it can retrieve the string “Contact Us” from the website homepage. If your website goes down, you can configure Pingdom so that it sends an email, Twitter, SMS, or iPhone alert. I use the Pingdom iPhone app which looks like this: 6. Host Tracker If your website does go down then you need some way of determining whether it is a problem with your local network or if your website is down for everyone. I use a website named Host-Tracker.com to check how badly a website is down. Here’s what the Host-Tracker website displays for the Superexpert.com website when the website can be successfully pinged from everywhere in the world: Notice that Host-Tracker pinged the Superexpert.com website from 68 locations including Roubaix, France and Scranton, PA. Debugging I mean debugging in the broadest possible sense. I use the following tools when building a website to verify that I have not made a mistake. 7. HTML Spell Checker Why doesn’t Visual Studio have a built-in spell checker? Don’t know – I’ve always found this mysterious. Fortunately, however, a former member of the ASP.NET team wrote a free spell checker that you can use with your ASP.NET pages. I find a spell checker indispensible. It is easy to delude yourself that you are capable of perfect spelling. I’m always super embarrassed when I actually run the spell checking tool and discover all of my spelling mistakes. The fastest way to add the HTML Spell Checker extension to Visual Studio is to select the menu option Tools, Extension Manager within Visual Studio. Click on Online Gallery and search for HTML Spell Checker: 8. IIS SEO Toolkit If people cannot find your website through Google then you should not even bother to create it. Microsoft has a great extension for IIS named the IIS Search Engine Optimization Toolkit that you can use to identify issue with your website that would hurt its page rank. You also can use this tool to quickly create a sitemap for your website that you can submit to Google or Bing. You can even generate the sitemap for an ASP.NET MVC website. Here’s what the report overview for the Superexpert.com website looks like: Notice that the Sueprexpert.com website had plenty of violations. For example, there are 65 cases in which a page has a broken hyperlink. You can drill into these violations to identity the exact page and location where these violations occur. 9. LinqPad If your ASP.NET website accesses a database then you should be using LINQ to Entities with the Entity Framework. Using LINQ involves some magic. LINQ queries written in C# get converted into SQL queries for you. If you are not careful about how you write your LINQ queries, you could unintentionally build a really badly performing website. LinqPad is a free tool that enables you to experiment with your LINQ queries. It even works with Microsoft SQL CE 4 and Azure. You can use LinqPad to execute a LINQ to Entities query and see the results. You also can use it to see the resulting SQL that gets executed against the database: 10. .NET Reflector I use .NET Reflector daily. The .NET Reflector tool enables you to take any assembly and disassemble the assembly into C# or VB.NET code. You can use .NET Reflector to see the “Source Code” of an assembly even when you do not have the actual source code. You can download a free version of .NET Reflector from the Redgate website. I use .NET Reflector primarily to help me understand what code is doing internally. For example, I used .NET Reflector with the Sprite and Image Optimization Framework to better understand how the MVC Image helper works. Here’s part of the disassembled code from the Image helper class: Summary In this blog entry, I’ve discussed several of the tools that I used to create the Superexpert.com website. These are tools that I use to improve the performance, improve the SEO, verify the uptime, or debug the Superexpert.com website. All of the tools discussed in this blog entry are free. Furthermore, all of these tools work with both ASP.NET Web Forms and ASP.NET MVC. Let me know if there are any tools that you use daily when building ASP.NET websites.

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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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