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  • Set property on usercontrol that can be used in custom panel in control... Silverlight

    - by Dimestore Cowboy
    I have a simple usercontrol that uses a simple custom panel where I just overrode the Orientation and Measure functions. What I want to do is to have a property in the usercontol to control the orientation So I basicaly have UserControl -- Listbox -- MyPanel And I want a property for the usercontrol that can be set in xaml (of type System.Windows.Controls.Orientation ) that I can bind to from my custom panel (or a different approach if binding isnt the right way to do it) It would be a bonus if that property could show up in the properties window and you could select vertical or horizontal. And a super bonus if I could change the property at design time and have the listbox/

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  • When I mark a property as transient, does the type matter?

    - by mystify
    For example, I make a fullName property and set it to transient. Does it matter what data type that property is, in this case? For example, does it matter if it's set to int or string? As far as I get it, a transient property is almost "ignored" by Core Data. I make my accessors for that and when someone accesses fullName, I simply construct a string and return that. Did I miss something?

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  • Accessing non-static combbox property in the static method.

    - by Harikrishna
    I have one combobox on the window form and I have one method which is declared with static like private static DataTable ParseTable(HtmlNode table) Now I want to use combobox in that method for using combobox property but I can not access any property of combobox or combobox itself.If I made the combobox declaration as static then it can be accessed in that static method.But any alternative way to access combbox property in that static method because I don't want to make combobox declaration as static.

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  • How can a ListBoxItem property be set in Silverlight at runtime?

    - by sympatric greg
    Given this XAML, I need to resize the userControl in response to user input. How can I set a new width for ListBoxItem (or perhaps the StackPanel)? <ScrollViewer x:Name="ScrollViewer" Margin="0" BorderBrush="Transparent" Width="165" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Hidden"> <ListBox x:Name="AttributeListBox" ItemsSource="{Binding Attributes}" BorderBrush="Red" Width="160" Foreground="AntiqueWhite" Background="Transparent" IsEnabled="False" HorizontalAlignment="Stretch"> <ListBox.ItemContainerStyle> <Style TargetType="ListBoxItem"> <Setter Property="HorizontalAlignment" Value="Stretch"/> <Setter Property="Width" Value="150"/> <Setter Property="Margin" Value="0,-2,0,0"/> <Setter Property="HorizontalContentAlignment" Value="Left" /> <Setter Property="Template" Value="{StaticResource ListBoxItemSansFocus}" /> </Style> </ListBox.ItemContainerStyle> <ListBox.ItemTemplate> <DataTemplate> <StackPanel x:Name="ListBoxItemStackPanel" HorizontalAlignment="Stretch" Orientation="Vertical" > <TextBlock FontSize="10" Text="{Binding Key}" Foreground="White" FontWeight="Bold" HorizontalAlignment="Stretch" Margin="2,0,0,0" TextWrapping="Wrap"/> <TextBlock FontSize="10" Text="{Binding Value}" Foreground="White" Margin="6,-2,0,0" TextWrapping="Wrap"/> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> </ScrollViewer>

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  • (Not So) Silly Objective-C inheritance problem when using property - GCC Bug?

    - by Ben Packard
    Update 2 - Many people are insisting I need to declare an iVar for the property. Some are saying not so, as I am using Modern Runtime (64 bit). I can confirm that I have been successfully using @property without iVars for months now. Therefore, I think the 'correct' answer is an explanation as to why on 64bit I suddenly have to explicitly declare the iVar when (and only when) i'm going to access it from a child class. The only one I've seen so far is a possible GCC bug (thanks Yuji). Not so simple after all... Update - I messed up one line of the original copy and paste - corrected. The @property call was missing (nonatomic, retain) but is a red herring - STILL NEED AN ANSWER! Thanks. I've been scratching my head with this for a couple of hours - I haven't used inheritance much. Here I have set up a simple Test B class that inherits from Test A, where an ivar is declared. But I get the compilation error that the variable is undeclared. This only happens when I add the property and synthesize declarations - works fine without them. TestA Header: #import <Cocoa/Cocoa.h> @interface TestA : NSObject { NSString *testString; } @end TestA Implementation is empty: #import "TestA.h" @implementation TestA @end TestB Header: #import <Cocoa/Cocoa.h> #import "TestA.h" @interface TestB : TestA { } @property (nonatomic, retain) NSString *testProp; @end TestB Implementation (Error - 'testString' is undeclared) #import "TestB.h" @implementation TestB @synthesize testProp; - (void)testing{ NSLog(@"test ivar is %@", testString); } @end

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  • Objective-C categories: Can I add a property for a method not in my category?

    - by Squeegy
    I want to use a category to make a method on the original class available as a property as well. Class A: @interface ClassA - (NSString*)foo; @end Class A category @interface ClassA (Properties) - (void)someCategoryMethod; @property (nonatomic, readonly) NSString *foo; @end Now when I do this, it seems to work, but it gives me warnings because I am not synthesizing the property in my category implementation. How do I tell the compiler everything is actually just fine since the original class synthesizes the property for me?

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  • How would you want to see software intellectual property protected?

    - by glenatron
    Reading answers to this question - and many other discussions of software patents - it seems that most of us as programmers feel that software patents are a bad idea. At the same time we are in the group most likely to lose out if our work is copied or stolen. So what level of Intellectual Property Protection does code and software need? Is copyright sufficient? Are patents necessary? As software is neither a physical object nor simple text, should we be thinking of a third path that falls somewhere between the two? Do we need any protection at all? If you had the facility to set up the law for this, what would you choose?

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  • VS2010's "Public Property <PropertyName> As <DataType> vs. Public var

    - by Velika2
    In VS2008, I used to type Public Property <PropName> As <dataType> and hit the Enter key and the IDE editor would automatically expand it out to a full blown property block. Now, from what I understand, a new feature of 2010 is that the compiler automatically "expands" the short syntax above into the same IL code that you would get with the full property GET AND SET sub methods that were are accustomed to seeing before in the editor. But functionality, how the heck is this any different than just having a Public class level variable? If the only diff is what it compiles to and if otehrwise there is no functional difference, isn't the new way less efficient than the old since it involves more code than just having a class level memory variable? Public as I thought that if you weren't going to have code behind your properties that they were essentially the same. I guess the diffrenece is that they just added the keyword "Property" but functionality, their is no diff, eh?

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  • How do I test if a property exists on a object before reading its value?

    - by Jeremy Rudd
    I'm attempting to read a property on a series of Sprites. This property may or may not be present on these objects, and may not even be declared, worse than being null. My code is: if (child["readable"] == true){ // this Sprite is activated for reading } And so Flash shows me: Error #1069: Property selectable not found on flash.display.Sprite and there is no default value. Is there a way to test if a property exists before reading its value? Something like: if (child.isProperty("readable") && child["readable"] == true){ // this Sprite is activated for reading }

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  • What's the order of execution in property setters when using IDataErrorInfo?

    - by Benny Jobigan
    Situation: Many times with WPF, we use INotifyPropertyChanged and IDataErrorInfo to enable binding and validation on our data objects. I've got a lot of properties that look like this: public SomeObject SomeData { get { return _SomeData; } set { _SomeData = value; OnPropertyChanged("SomeData"); } } Of course, I have an appropriate overridden IDataErrorInfo.this[] in my class to do validation. Question: In a binding situation, when does the validation code get executed? When is the property set? When is the setter code executed? What if the validation fails? For example: User enters new data. Binding writes data to property. Property set method is executed. Binding checks this[] for validation. If the data is invalid, the binding sets the property back to the old value. Property set method is executed again. This is important if you are adding "hooks" into the set method, like: public string PathToFile { get { return _PathToFile; } set { if (_PathToFile != value && // prevent unnecessary actions OnPathToFileChanging(value)) // allow subclasses to do something or stop the setter { _PathToFile = value; OnPathToFileChanged(); // allow subclasses to do something afterwards OnPropertyChanged("PathToFile"); } } }

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  • Within a Visual Studio 2008 Add-In, how can I tell which interfaces a class' property implements?

    - by Tim Stewart
    In a Visual Studio Add-In, I'm enumerating over the members of a class in the current source file. When I encounter a property (e.g. CodeElement.Kind == vsCMElement.vsCMElementProperty) I cast that CodeElement to a CodeProperty and I can see the property's name and type. What I'm having a problem with is getting a list of the property's implemented interfaces. I'm wondering if this is because the implemented interfaces might be in assemblies that Visual Studio doesn't "know" about. Is there a way to get the list of interfaces that a property implements? Thanks.

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  • How can I use BeanUtils copyProperties to copy from boolean to Boolean?

    - by carrier
    BeanUtils copyProperties, out of the box, doesn't seem to handle copying from Boolean object properties to boolean primitive properties. I figured I could create and register a converter to handle this, but that just didn't seem to work. So, how can I use BeanUtils to copy the properties from class Source to class Destination where: public class Destination { private boolean property; public boolean isProperty() { return property; } public void setProperty(boolean property) { this.property = property; } } public class Source{ private Boolean property; public Boolean getProperty() { return property; } public void setProperty(Boolean property) { this.property = property; } }

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  • Why does VerticalScrollBarVisibility not work in a style in Silverlight?

    - by Edward Tanguay
    VerticalScrollBarVisibility works when I define it inline like this: <UserControl x:Class="TestScrollBar.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"> <UserControl.Resources> <Style TargetType="TextBox" x:Key="EditListContainerContentMultiLineTwoColumn"> <Setter Property="AcceptsReturn" Value="True"/> <Setter Property="Width" Value="400"/> <Setter Property="Height" Value="300"/> <Setter Property="IsReadOnly" Value="False"/> <Setter Property="Margin" Value="0 0 0 20"/> <Setter Property="HorizontalAlignment" Value="Left"/> <Setter Property="TextWrapping" Value="Wrap" /> </Style> </UserControl.Resources> <Grid x:Name="LayoutRoot" Background="White" Margin="10"> <StackPanel HorizontalAlignment="Left"> <TextBox Text="this is a test" Style="{StaticResource EditListContainerContentMultiLineTwoColumn}" VerticalScrollBarVisibility="Auto" /> </StackPanel> </Grid> </UserControl> But when I put VerticalScrollBarVisibility in a style, it shows me a blank screen: <UserControl x:Class="TestScrollBar.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"> <UserControl.Resources> <Style TargetType="TextBox" x:Key="EditListContainerContentMultiLineTwoColumn"> <Setter Property="VerticalScrollBarVisibility" Value="Auto"/> <Setter Property="AcceptsReturn" Value="True"/> <Setter Property="Width" Value="400"/> <Setter Property="Height" Value="300"/> <Setter Property="IsReadOnly" Value="False"/> <Setter Property="Margin" Value="0 0 0 20"/> <Setter Property="HorizontalAlignment" Value="Left"/> <Setter Property="TextWrapping" Value="Wrap" /> </Style> </UserControl.Resources> <Grid x:Name="LayoutRoot" Background="White" Margin="10"> <StackPanel HorizontalAlignment="Left"> <TextBox Text="this is a test" Style="{StaticResource EditListContainerContentMultiLineTwoColumn}" /> </StackPanel> </Grid> </UserControl> In WPF it works works fine. How can I get VerticalScrollBarVisibility to work in a style?

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  • How can I map "insert='false' update='false'" on a composite-id key-property which is also used in a one-to-many FK?

    - by Gweebz
    I am working on a legacy code base with an existing DB schema. The existing code uses SQL and PL/SQL to execute queries on the DB. We have been tasked with making a small part of the project database-engine agnostic (at first, change everything eventually). We have chosen to use Hibernate 3.3.2.GA and "*.hbm.xml" mapping files (as opposed to annotations). Unfortunately, it is not feasible to change the existing schema because we cannot regress any legacy features. The problem I am encountering is when I am trying to map a uni-directional, one-to-many relationship where the FK is also part of a composite PK. Here are the classes and mapping file... CompanyEntity.java public class CompanyEntity { private Integer id; private Set<CompanyNameEntity> names; ... } CompanyNameEntity.java public class CompanyNameEntity implements Serializable { private Integer id; private String languageId; private String name; ... } CompanyNameEntity.hbm.xml <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.jboss.org/dtd/hibernate/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.example"> <class name="com.example.CompanyEntity" table="COMPANY"> <id name="id" column="COMPANY_ID"/> <set name="names" table="COMPANY_NAME" cascade="all-delete-orphan" fetch="join" batch-size="1" lazy="false"> <key column="COMPANY_ID"/> <one-to-many entity-name="vendorName"/> </set> </class> <class entity-name="companyName" name="com.example.CompanyNameEntity" table="COMPANY_NAME"> <composite-id> <key-property name="id" column="COMPANY_ID"/> <key-property name="languageId" column="LANGUAGE_ID"/> </composite-id> <property name="name" column="NAME" length="255"/> </class> </hibernate-mapping> This code works just fine for SELECT and INSERT of a Company with names. I encountered a problem when I tried to update and existing record. I received a BatchUpdateException and after looking through the SQL logs I saw Hibernate was trying to do something stupid... update COMPANY_NAME set COMPANY_ID=null where COMPANY_ID=? Hibernate was trying to dis-associate child records before updating them. The problem is that this field is part of the PK and not-nullable. I found the quick solution to make Hibernate not do this is to add "not-null='true'" to the "key" element in the parent mapping. SO now may mapping looks like this... CompanyNameEntity.hbm.xml <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.jboss.org/dtd/hibernate/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.example"> <class name="com.example.CompanyEntity" table="COMPANY"> <id name="id" column="COMPANY_ID"/> <set name="names" table="COMPANY_NAME" cascade="all-delete-orphan" fetch="join" batch-size="1" lazy="false"> <key column="COMPANY_ID" not-null="true"/> <one-to-many entity-name="vendorName"/> </set> </class> <class entity-name="companyName" name="com.example.CompanyNameEntity" table="COMPANY_NAME"> <composite-id> <key-property name="id" column="COMPANY_ID"/> <key-property name="languageId" column="LANGUAGE_ID"/> </composite-id> <property name="name" column="NAME" length="255"/> </class> </hibernate-mapping> This mapping gives the exception... org.hibernate.MappingException: Repeated column in mapping for entity: companyName column: COMPANY_ID (should be mapped with insert="false" update="false") My problem now is that I have tryed to add these attributes to the key-property element but that is not supported by the DTD. I have also tryed changing it to a key-many-to-one element but that didn't work either. So... How can I map "insert='false' update='false'" on a composite-id key-property which is also used in a one-to-many FK?

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  • How are design-by-contract and property-based testing (QuickCheck) related?

    - by Todd Owen
    Is their only similarity the fact that they are not xUnit (or more precisely, not based on enumerating specific test cases), or is it deeper than that? Property-based testing (using QuickCheck, ScalaCheck, etc) seem well-suited to a functional programming style where side-effects are avoided. On the other hand, Design by Contract (as implemented in Eiffel) is more suited to OOP languages: you can express post-conditions about the effects of methods, not just their return values. But both of them involve testing assertions that are true in general (rather than assertions that should be true for a specific test case). And both can be tested using randomly generated inputs (with QuickCheck this is the only way, whereas with Eiffel I believe it is an optional feature of the AutoTest tool). Is there an umbrella term to encompass both approaches? Or am I imagining a relationship that doesn't really exist.

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  • Cannot save all of the property settings for this Web Part.

    - by ybbest
    I would like to display all the items of custom content type of Animals in a SharePoint content query WebPart. After choosing the appropriate values in the web part editor and click on Save I got this error: Cannot save all of the property settings for this Web Part. There is a problem with one or more of the field values below. But when I examine all the values below , it does not flag any error information. I finally manage to locate the error flag after I expand the presentation section. I then delete the text in the Link textbox , now I can save the settings. However , I think the error message should have been more specific so that users can quickly locate the error. The worst part for this is that I did not even change anything in the presentation section, I merely configure the Source in the Query section. Well, I guess I am still new to SharePoint, I just have to get used to these generic error message ):

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  • Is it possible to override a property and return a derived type in VB.NET?

    - by Casey
    Consider the following classes representing an Ordering system: Public Class OrderBase Public MustOverride Property OrderItem() as OrderItemBase End Class Public Class OrderItemBase End Class Now, suppose we want to extend these classes to a more specific set of order classes, keeping the aggregate nature of OrderBase: Public Class WebOrder Inherits OrderBase Public Overrides Property OrderItem() as WebOrderItem End Property End Class Public Class WebOrderItem Inherits OrderItemBase End Class The Overriden property in the WebOrder class will cause an error stating that the return type is different from that defined in OrderBase... however, the return type is a subclass of the type defined in OrderBase. Why won't VB allow this?

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  • What is the best way to declare a property?

    - by Simon
    Hi. We declare properties using the @property keyword and synthesize it in the implementation file. My question is, What if I declare a property using the @property keyword and also declare a variable in the interface block with the same name? For example, consider the following code, Interface: @interface myClass : NSObject { NSString *myClass_name; // LINE 1 } @property(nonatomic, retain) NSString *myClass_name; // LINE 2 @end Implementation: @implementation myClass @synthesize myClass_name // LINE 3 @end Declaring myClass_name in LINE 1 will make any problem? Like any reference problem or any unnecessary memory consumption problem?

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  • Beginning with Datampper, Association question

    - by Ian
    I'm just diving into Datamapper (and Sinatra) and have a question about associations. Below are some models I have. This is what I want to implemented. I'm having an issue with Workoutitems and Workout. Workout will be managed separately, but Workoutitems has a single workout associated with each row. Workout - just a list of types of workouts (run, lift, situps, etc) Selected workout - this is the name of a set of workouts, along with notes by the user and trainer. It has a collection of N workoutitems Workoutitems - this takes a workout and a number of repetitions to it that go in the workout set. class Workout include DataMapper::Resource property :id, Serial #PK id property :name, String, :length=50,:required=true # workout name property :description, String, :length=255 #workout description end class Selectedworkout include DataMapper::Resource property :id, Serial property :name, String, :length=50, :required=true property :workout_time, String, :length=20 property :user_notes, String, :length=255 property :coach_notes, String, :length=255 has n, :workoutitems end class Workoutitem include DataMapper::Resource property :id, Serial property :reps, String, :length=50, :required=true belongs_to :selectedworkout end

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  • Where should the line between property and method be?

    - by Catskul
    For many situations it is obvious whether something should be a property or a method however there are items that might be considered ambiguous. Obvious Properties: "name" "length" Obvious Methods: "SendMessage" "Print" Ambiguous: "Valid" / "IsValid" / "Validate" "InBounds" / "IsInBounds" / "CheckBounds" "AverageChildValue" / "CalcAverageChildValue" "ColorSaturation" / "SetColorSaturation" I suppose I would lean towards methods for the ambiguous, but does anyone know of a rule or convention that helps decide this? E.g. should all properties be O(1)? Should a property not be able to change other data (ColorSaturation might change R,G,B values)? Should it not be a property if there is calculation or aggregation? Just from an academic perspective, (and not because I think it's a good idea) is there a reason not to go crazy with properties and just make everything that is an interrogation of the class without taking an argument, and everything that can be changed about the class with a single argument and cant fail, a property?

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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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