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  • Why does python use 'magic methods'?

    - by Greg Beech
    I've been playing around with Python recently, and one thing I'm finding a bit odd is the extensive use of 'magic methods', e.g. to make its length available an object implements a method def __len__(self) and then it is called when you write len(obj). I was just wondering why objects don't simply define a len(self) method and have it called directly as a member of the object, e.g. obj.len()? I'm sure there must be good reasons for Python doing it the way it does, but as a newbie I haven't worked out what they are yet.

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  • PHP array : simple question about multidimensional array

    - by Tristan
    Hello, i've got a SQL query which returns multiple rows, and i have : $data = array( "nom" => $row['nom'] , "prix" => $row['rapport'], "average" => "$moyenne_ge" ); which is perfect, but only if my query returns one row. i tried that : $data = array(); $data[$row['nom']]["nom"] = $row['nom'] ; ... $data[$row['nom']]['average'] = "$moyenne_ge"; in order to have : $data[brand1][nom] = brand1 $data[brand1][average] = 150$ $data[brand2][nom] = brand2 $data[brand2][average] = 20$ ... but when i do : json_encode($data) i only have the latest JSON object instead of all JSON object from my request as if my array has only one brand instead of 10. I guess i did something stupid somewhere. Thanks for your help

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  • zoom_changed only triggers once in google maps api version 3 using MVC

    - by fredrik
    Hi, I'm trying to use the MVC objects in google maps version 3. What I can't seem to figure out is why my zoom_changed method is only invoked once. When I first load the map the zoom_changed method is invoked. But not when I zoom on the map. function MarkerWidget (options) { this.setValues(options); this.set('zoom', this.map.zoom); var marker = new google.maps.Marker({ icon : this.icon, mouseOverIcon : this.mouseOverIcon, orgIcon : this.orgIcon }); marker.bindTo('map', this); marker.bindTo('position', this); google.maps.event.addListener(marker, 'mouseover', this.onmouseover); google.maps.event.addListener(marker, 'mouseout', this.onmouseout); } MarkerWidget.prototype = new google.maps.MVCObject(); MarkerWidget.prototype.zoom_changed = function () { $.log(this, new Date()); } Shouldn't the map object fire the zoom event and notify all object's that has "this.set('zoom', this.map.zoom)" ? ..fredrik

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  • Is this (Lock-Free) Queue Implementation Thread-Safe?

    - by Hosam Aly
    I am trying to create a lock-free queue implementation in Java, mainly for personal learning. The queue should be a general one, allowing any number of readers and/or writers concurrently. Would you please review it, and suggest any improvements/issues you find? Thank you. import java.util.concurrent.atomic.AtomicReference; public class LockFreeQueue<T> { private static class Node<E> { E value; volatile Node<E> next; Node(E value) { this.value = value; } } private AtomicReference<Node<T>> head, tail; public LockFreeQueue() { // have both head and tail point to a dummy node Node<T> dummyNode = new Node<T>(null); head = new AtomicReference<Node<T>>(dummyNode); tail = new AtomicReference<Node<T>>(dummyNode); } /** * Puts an object at the end of the queue. */ public void putObject(T value) { Node<T> newNode = new Node<T>(value); Node<T> prevTailNode = tail.getAndSet(newNode); prevTailNode.next = newNode; } /** * Gets an object from the beginning of the queue. The object is removed * from the queue. If there are no objects in the queue, returns null. */ public T getObject() { Node<T> headNode, valueNode; // move head node to the next node using atomic semantics // as long as next node is not null do { headNode = head.get(); valueNode = headNode.next; // try until the whole loop executes pseudo-atomically // (i.e. unaffected by modifications done by other threads) } while (valueNode != null && !head.compareAndSet(headNode, valueNode)); T value = (valueNode != null ? valueNode.value : null); // release the value pointed to by head, keeping the head node dummy if (valueNode != null) valueNode.value = null; return value; }

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  • LINQ query checks for null

    - by user300992
    I have a userList, some users don't have a name (null). If I run the first LINQ query, I got an error saying "object reference not set to an instance of an object" error. var temp = (from a in userList where ((a.name == "john") && (a.name != null)) select a).ToList(); However, if I switch the order by putting the checking for null in front, then it works without throwing any error: var temp = (from a in userList where ((a.name != null) && (a.name == "john")) select a).ToList(); Why is that? If that's pure C# code (not LINQ), I think both would be the same. I don't have SQL profiler, I am just curious what will be the difference when they are being translated on SQL level.

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  • Incorrect decrement of the reference count

    - by idober
    I have the following problem: In one flow of the execution I use alloc, and on the other flow, alloc is not needed. At the end of the if statement, in any case, I release the object. When I do 'build and Analize' I get an error: 'Incorrect decrement of the reference count of an object is not owned by the caller'. How to solve that? UIImage *image; int RandomIndex = arc4random() % 10; if (RandomIndex<5) { image = [[UIImage alloc] initWithContentsOfFile:@"dd"]; } else { image = [UIImage imageNamed:@"dd"]; } UIImageView *imageLabel =[[UIImageView alloc] initWithImage:image]; [image release]; [imageLabel release];

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  • Making selectable again a WPF TreeviewITem after the first click

    - by pileggi
    Hi, I have a TreeVIew WPF with 2 Levels of Data. I have deleted the ToogleButton from the TreeViewItemTemplate. Now I'd like to expand / collapse the groups with a single mouse-click (not with a double click as the default behaviour). I have tried in this way: Private Sub tvArt_SelectedItemChanged(ByVal sender As System.Object, _ ByVal e As RoutedPropertyChangedEventArgs(Of System.Object)) Handles tvArt.SelectedItemChanged If e.NewValue Is Nothing = False Then Dim ri As P_RicambiItem = TryCast(e.NewValue, P_RicambiItem) If ri Is Nothing = False Then If ri.isExpanded Then ri.isExpanded = False Else ri.isExpanded = True End If ri.isSelected = False End If End If End Sub Using my properties "isExpanded" and "isSelected" in the collection data source. But it works only halfway: after the first click, infact, I can't click for a second time on the same item, because, even if I've deselected it, the event handler "remembers" that it was the last selected item and it doesn't capture the event "SelectedItemChanged". How can I do? Thanks a lot, Pileggi

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  • Null Reference Exception on MVVM pattern

    - by Mohit Deshpande
    System.NullReferenceException Object reference not set to an instance of an object. at Microsoft.Windows.Design.DocumentModel.Trees.MarkupDocumentTreeManager.<FindMarkupNodePath>d__0.MoveNext() at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable1 source) at MS.Internal.Services.DocumentInformationServiceImpl.get_Root() at MS.Internal.Designer.VSDesigner.Load() at MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedView.Load() at MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedDesignerFactory.Load(IsolatedView view) at MS.Internal.Host.Isolation.IsolatedDesigner.BootstrapProxy.LoadDesigner(IsolatedDesignerFactory factory, IsolatedView view) at MS.Internal.Host.Isolation.IsolatedDesigner.BootstrapProxy.LoadDesigner(IsolatedDesignerFactory factory, IsolatedView view) at MS.Internal.Host.Isolation.IsolatedDesigner.Load() at MS.Internal.Designer.DesignerPane.LoadDesignerView() I keep getting this exception and then intellisense stops working in a XAML text editor. Any ideas why?

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  • jQuery won't parse my JSON from AJAX query

    - by littlecharva
    Hi, I'm having difficulty parsing some JSON data returned from my server using jQuery.ajax() To perform the AJAX I'm using: $.ajax({ url: myUrl, cache: false, dataType: "json", success: function(data){ ... }, error: function(e, xhr){ ... } }); And if I return an array of items then it works fine: [ { title: "One", key: "1" }, { title: "Two", key: "2" } ] The success function is called and receives the correct object. However, when I'm trying to return a single object: { title: "One", key: "1" } The error function is called and xhr contains 'parsererror'. I've tried wrapping the JSON in parenthesis on the server before sending it down the wire, but it makes no difference. Yet if I paste the content into a string in Javascript and then use the eval() function, it evaluates it perfectly. Any ideas what I'm doing wrong? Anthony

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  • JAVA Classes in Game programming.

    - by Gabriel A. Zorrilla
    I'm doing a little strategy game to help me learn Java in a fun way. The thing is I visioned the units as objects that would self draw on the game map (using images and buffering) and would react to the mouse actions with listeners attached to them. Now, based on some tutorials I've been reading regarding basic game programming, all seems to be drawn in the Graphics method of my Map class. If a new unit emerges, i just update the Map.Graphics method, it's not as easy as making a new Unit object which would self draw... In this case, I'd be stuck with a whole bunch of Map methods instead of using classes for rendering new things. So my question is, is it possible to use classes for rendering units, interface objects, etc, or i'll have to create methods and just do some kind of structural programming instead of object oriented? I'm a little bit confused and I'd like to have a mental blueprint of how things would be organized. Thanks!

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  • Get XAML from WPF Custom RichTextFormat

    - by Erika
    I've looked at other posts, but i cant seem to find something that works. I have a custom control WPF RichTextBox and would like to obtain the XAML from this control. I have tried the following //rt is the name of this particular custom richtextbox TextRange range = new TextRange(rt.Document.ContentStart, rt.Document.ContentEnd); MemoryStream stream = new MemoryStream(); range.Save(stream, DataFormats.Xaml); string xamlText = Encoding.UTF8.GetString(stream.ToArray()); return xamlText; but this doesnt seem to work :s I can access the rt.Document.Content start etc but it seems to crash there "Object Reference not set to instance of an object". I am using the richtextbox directly from the .xaml.cs so it should be initiated and so on :s. Any Ideas or other ways to get the XAML from a richtextbox pls? (i'm requiring the XAML cos i actually want to get the HTML.. if theres some other direct manner perhaps?)

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  • Setting HTML Text Element value

    - by Gpx
    Hi, in my C# WPF prog i´am trying to set a value of a HTML Text Element which is defined like: <input name="tbBName" type="text" id="tbBName" tabindex="1" /> What i found about it and tried is: mshtml.HTMLDocument doc = (mshtml.HTMLDocument)webBrowser1.Document; mshtml.HTMLInputTextElement tbName = (mshtml.HTMLInputTextElement)doc.getElementsByName("tbBName"); tbName.value = "Test"; But i got the exception: Unable to cast COM object of type 'System.__ComObject' to interface type 'mshtml.HTMLInputTextElement'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{3050F520-98B5-11CF-BB82-00AA00BDCE0B}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)). I know what it says but i dont know which object i can use to access the Texbox. Thanks for any answers.

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  • str is not callable error in python .

    - by mekasperasky
    import sys import md5 from TOSSIM import * from RadioCountMsg import * t = Tossim([]) #The Tossim object is defined here m = t.mac()#The mac layer is defined here , in which the communication takes place r = t.radio()#The radio communication link object is defined here , as the communication needs Rf frequency to transfer t.addChannel("RadioCountToLedsC", sys.stdout)# The various channels through which communication will take place t.addChannel("LedsC", sys.stdout) #The no of nodes that would be required in the simulation has to be entered here print("enter the no of nodes you want ") n=input() for i in range(0, n): m = t.getNode(i) m.bootAtTime((31 + t.ticksPerSecond() / 10) * i + 1) #The booting time is defined so that the time at which the node would be booted is given f = open("topo.txt", "r") #The topography is defined in topo.txt so that the RF frequencies of the transmission between nodes are are set lines = f.readlines() for line in lines: s = line.split() if (len(s) > 0): if (s[0] == "gain"): r.add(int(s[1]), int(s[2]), float(s[3])) #The topogrography is added to the radio object noise = open("meyer-heavy.txt", "r") #The noise model is defined for the nodes lines = noise.readlines() for line in lines: str = line.strip() if (str != ""): val = int(str) for i in range(0, 4): t.getNode(i).addNoiseTraceReading(val) for i in range (0, n): t.getNode(i).createNoiseModel() #The noise model is created for each node for i in range(0,n): t.runNextEvent() fk=open("key.txt","w") for i in range(0,n): if i ==0 : key=raw_input() fk.write(key) ak=key key=md5.new() key.update(str(ak)) ak=key.digest() fk.write(ak) fk.close() fk=open("key.txt","w") plaint=open("pt.txt") for i in range(0,n): msg = RadioCountMsg() msg.set_counter(7) pkt = t.newPacket()#A packet is defined according to a certain format print("enter message to be transported") ms=raw_input()#The message to be transported is taken as input #The RC5 encryption has to be done here plaint.write(ms) pkt.setData(msg.data) pkt.setType(msg.get_amType()) pkt.setDestination(i+1)#The destination to which the packet will be sent is set print "Delivering " + " to" ,i+1 pkt.deliver(i+1, t.time() + 3) fk.close() print "the key to be displayed" ki=raw_input() fk=open("key.txt") for i in range(0,n): if i==ki: ms=fk.readline() for i in range(0,n): msg=RadioCountMsg() msg.set_counter(7) pkt=t.newPacket() msg.data=ms pkt.setData(msg.data) pkt.setType(msg.get_amType()) pkt.setDestination(i+1) pkt.deliver(i+1,t.time()+3) #The key has to be broadcasted here so that the decryption can take place for i in range(0, n): t.runNextEvent(); this code gives me error here key.update(str(ak)) . when i run a similar code on the python terminal there is no such error but this code pops up an error . why so?

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  • Scala type conversion error, need help!

    - by Mansoor Ashraf
    Hello I am getting a weird error when trying to use a Java map in Scala. This is the snippet of code val value:Double = map.get(name) if (value eq null) map.put(name, time) else map.put(name, value + time) the map is defined as val map=new ConcurrentHashMap[String,Double] and this is the error I am getting error: type mismatch; found : Double required: ?{val eq: ?} Note that implicit conversions are not applicable because they are ambiguous: both method double2Double in object Predef of type (Double)java.lang.Double and method doubleWrapper in object Predef of type (Double)scala.runtime.RichDouble are possible conversion functions from Double to ?{val eq: ?} if (value eq null) map.put(name, time) I am new to Scala so I am having a hard time parsing the stacktrace. Any help would be appreciated

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  • Instantiating a context in LINQ to Entities

    - by Jagd
    I've seen two different manners that programmers approach when creating an entity context in their code. The first is like such, and you can find it all over the MSDN code examples: public void DoSomething() { using TaxableEducationEntities context = new TaxableEducationEntities()) { // business logic and whatever else } } The second is to create the context as a private attribute in some class that encapsulates your business logic. So you would have something like: public class Education_LINQ { private TaxableEducationEntities context = new TaxableEducationEntities(); public void DoSomething() { var result = from a in context.luAction select a; // business logic and whatever else } } Which way is more efficient? Assume that you have two methods, one called DoSomething1() and another called DoSomething2(), and both methods incorporate the using statement to open the context and do whatever with it. Were you to call one method after the other, would there be any superfluous overhead going on, since essentially both methods create the context and then clean it up when they're done? As opposed to having just one private attribute that is created when a class object is instantiated, and then in turn cleaned up when the object goes out of scope?

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  • WPF: Soft deletes and binding?

    - by aks
    I have custom objects which implement INotifyProperyChanged and now I'm wondering if it is possible to implement soft delete which would play nicely with binding? Each object would have a IsDeleted property and if this property would be set to true than it would not be displayed in GUI. I was thinking about making a custom markup extension which would decorate Binding class but it hadn't worked out as expected. Now I'm considering using MultiBinding with IsDeleted as one of bound properties so that converter would be able to figure out which object is deleted. But this solution sounds quite complicated and boring. Does anybody have an idea how to implement soft deletes for binding?

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  • C# generic list <T> how to get the type of T?

    - by Daok
    Hello, Let say I have a List< T > abc = new List< T >; inside a class public class MyClass<T>//.... Later, when I initialize the class the T because MyTypeObject1. So I have a generic list of List< MyTypeObject1 >. I would like to know, what type of object the list of my class contain. Example, the list called abc contain what type of object? I cannot do abc[0].GetType(); because the list might contain 0 element. How can I do it?

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  • Winforms Hotkey, Help?

    - by Di4g0n4leye
    namespace WebBrowser { public partial class MainForm : Form { public MainForm() { InitializeComponent(); } int GetPixel(int x, int y) { Bitmap bmp = new Bitmap(1, 1, PixelFormat.Format32bppPArgb); Graphics grp = Graphics.FromImage(bmp); grp.CopyFromScreen(new Point(x,y), Point.Empty, new Size(1,1)); grp.Save(); return bmp.GetPixel(0, 0).ToArgb(); } void Button1Click(object sender, EventArgs e) { int x = Cursor.Position.X; int y = Cursor.Position.Y; int pixel = GetPixel(x,y); textBox1.Text = pixel.ToString(); } void MainFormLoad(object sender, EventArgs e) { webBrowser1.Navigate("http://google.com"); } } } } i want to add a hotkey that call Button1 on Press, How can that be done?

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  • Eager loading vs. many queries with PHP, SQLite

    - by Mike
    I have an application that has an n+1 query problem, but when I implemented a way to load the data eagerly, I found absolutely no performance gain. I do use an identity map, so objects are only created once. Here's a benchmark of ~3000 objects. first query + first object creation: 0.00636100769043 sec. memory usage: 190008 bytes iterate through all objects (queries + objects creation): 1.98003697395 sec. memory usage: 7717116 bytes And here's one when I use eager loading. query: 0.0881109237671 sec. memory usage: 6948004 bytes object creation: 1.91053009033 sec. memory usage: 12650368 bytes iterate through all objects: 1.96605396271 sec. memory usage: 12686836 bytes So my questions are Is SQLite just magically lightning fast when it comes to small queries? (I'm used to working with MySQL.) Does this just seem wrong to anyone? Shouldn't eager loading have given much better performance?

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  • Adding scope variable to an constructor

    - by Lupus
    I'm trying to create a class like architecture on javascript but stuck on a point. Here is the code: var make = function(args) { var priv = args.priv, cons = args.cons, pub = args.pub; return function(consParams) { var priv = priv, cons = args.cons; cons.prototype.constructor = cons; cons.prototype = $.extend({}, pub); if (!$.isFunction(cons)) { throw new Hata(100001); } return new cons(consParams); } }; I'm trying to add the priv variable on the returned function objects's scope and object scope of the cons.prototype but I could not make it; Here is the usage of the make object: var myClass = make({ cons: function() { alert(this.acik); }, pub: { acik: 'acik' }, priv: { gizli: 'gizli' } }) myObj = myClass(); PS: Please forgive my english...

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  • Asynchronous Sockets - Handling false socket.AcceptAsync values

    - by David
    The Socket class has a method .AcceptAsync which either returns true or false. I'd thought the false return value was an error condition, but in the samples Microsoft provide for Async sockets they call the callback function synchronously after checking for failure, as shown here: public void StartAccept(SocketAsyncEventArgs acceptEventArg) { if (acceptEventArg == null) { acceptEventArg = new SocketAsyncEventArgs(); acceptEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(AcceptEventArg_Completed); } else { // socket must be cleared since the context object is being reused acceptEventArg.AcceptSocket = null; } m_maxNumberAcceptedClients.WaitOne(); bool willRaiseEvent = listenSocket.AcceptAsync(acceptEventArg); if (!willRaiseEvent) { ProcessAccept(acceptEventArg); } } /// <summary> /// This method is the callback method associated with Socket.AcceptAsync operations and is invoked /// when an accept operation is complete /// </summary> void AcceptEventArg_Completed(object sender, SocketAsyncEventArgs e) { ProcessAccept(e); } Why do they do this? It defeats the purpose of asynchronous sockets and stops the method from returning.

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  • Why does DataSet.HasChanges() return true if called in the same function as change but false otherwi

    - by Chapso
    Assuming that the buttons are being clicked in order, the following code modifies row 1 in a .net DataSet, then row 0. HasChanges returns true, but GetChanges only gives me the change for row 0. If I comment out the line in the button2 click event that modifies row 0, then HasChanges returns false. Can anyone explain to me why HasChanges() and GetChanges() only return true when they are called in the same function as the change to the DataSet? Protected Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click __ds1.Tables(0).Rows(1)("EmployeeName") = "TestStuff" End Sub Protected Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click __ds1.Tables(0).Rows(0)("EmployeeName") = "TestStuff" If __ds1.HasChanges(DataRowState.Modified Or DataRowState.Added) Then __ds2 = __ds1.GetChanges(DataRowState.Modified _ Or DataRowState.Added) GridView3.DataSource = __ds2.Tables("Users").DefaultView GridView3.DataBind() Else End If End Sub

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  • Python: convert buffer type of SQLITE column into string

    - by Volatil3
    I am new to Python 2.6. I have been trying to fetch date datetime value which is in yyyy-mm-dd hh:m:ss format back in my Python program. On checking the column type in Python I get the error: 'buffer' object has no attribute 'decode'. I want to use the strptime() function to split the date data and use it but I can't find how to convert a buffer to string. The following is a sample of my code (also available here): conn = sqlite3.connect("mrp.db.db", detect_types=sqlite3.PARSE_DECLTYPES) cursor = conn.cursor() qryT = """ SELECT dateDefinitionTest FROM t WHERE IDproject = 4 AND IDstatus = 5 ORDER BY priority, setDate DESC """ rec = (4,4) cursor.execute(qryT,rec) resultsetTasks = cursor.fetchall() cursor.close() # closing the resultset for item in resultsetTasks: taskDetails = {} _f = item[10].decode("utf-8") The exception I get is: 'buffer' object has no attribute 'decode'

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  • CheckBox ListView SelectedValues DependencyProperty Binding

    - by Ristogod
    I am writing a custom control that is a ListView that has a CheckBox on each item in the ListView to indicate that item is Selected. I was able to do so with the following XAML. <ListView x:Class="CheckedListViewSample.CheckBoxListView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" mc:Ignorable="d"> <ListView.Style> <Style TargetType="{x:Type ListView}"> <Setter Property="SelectionMode" Value="Multiple" /> <Style.Resources> <Style TargetType="ListViewItem"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="ListViewItem"> <Border BorderThickness="{TemplateBinding Border.BorderThickness}" Padding="{TemplateBinding Control.Padding}" BorderBrush="{TemplateBinding Border.BorderBrush}" Background="{TemplateBinding Panel.Background}" SnapsToDevicePixels="True"> <CheckBox IsChecked="{Binding IsSelected, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListViewItem}}}"> <CheckBox.Content> <ContentPresenter Content="{TemplateBinding ContentControl.Content}" ContentTemplate="{TemplateBinding ContentControl.ContentTemplate}" HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding Control.VerticalContentAlignment}" SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" /> </CheckBox.Content> </CheckBox> </Border> </ControlTemplate> </Setter.Value> </Setter> </Style> </Style.Resources> </Style> </ListView.Style> </ListView> I however am trying to attempt one more feature. The ListView has a SelectedItems DependencyProperty that returns a collection of the Items that are checked. However, I need to implement a SelectedValues DependencyProperty. I also am implementing a SelectedValuesPath DependencyProperty. By using the SelectedValuesPath, I indicate the path where the values are found for each selected item. So if my items have an ID property, I can specify using the SelectedValuesPath property "ID". The SelectedValues property would then return a collection of ID values. I have this working also using this code in the code-behind: using System.Windows; using System.Windows.Controls; using System.ComponentModel; using System.Collections; using System.Collections.Generic; namespace CheckedListViewSample { /// <summary> /// Interaction logic for CheckBoxListView.xaml /// </summary> public partial class CheckBoxListView : ListView { public static DependencyProperty SelectedValuesPathProperty = DependencyProperty.Register("SelectedValuesPath", typeof(string), typeof(CheckBoxListView), new PropertyMetadata(string.Empty, null)); public static DependencyProperty SelectedValuesProperty = DependencyProperty.Register("SelectedValues", typeof(IList), typeof(CheckBoxListView), new PropertyMetadata(new List<object>(), null)); [Category("Appearance")] [Localizability(LocalizationCategory.NeverLocalize)] [Bindable(true)] public string SelectedValuesPath { get { return ((string)(base.GetValue(CheckBoxListView.SelectedValuesPathProperty))); } set { base.SetValue(CheckBoxListView.SelectedValuesPathProperty, value); } } [Bindable(true)] [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)] [Category("Appearance")] public IList SelectedValues { get { return ((IList)(base.GetValue(CheckBoxListView.SelectedValuesPathProperty))); } set { base.SetValue(CheckBoxListView.SelectedValuesPathProperty, value); } } public CheckBoxListView() : base() { InitializeComponent(); base.SelectionChanged += new SelectionChangedEventHandler(CheckBoxListView_SelectionChanged); } private void CheckBoxListView_SelectionChanged(object sender, SelectionChangedEventArgs e) { List<object> values = new List<object>(); foreach (var item in SelectedItems) { if (string.IsNullOrWhiteSpace(SelectedValuesPath)) { values.Add(item); } else { try { values.Add(item.GetType().GetProperty(SelectedValuesPath).GetValue(item, null)); } catch { } } } base.SetValue(CheckBoxListView.SelectedValuesProperty, values); e.Handled = true; } } } My problem is that my binding only works one way right now. I'm having trouble trying to figure out how to implement my SelectedValues DependencyProperty so that I could Bind a Collection of values to it, and when the control is loaded, the CheckBoxes are checked with items that have values that correspond to the SelectedValues. I've considered using the PropertyChangedCallBack event, but can't quite figure out how I could write that to achieve my goal. I'm also unsure of how I find the correct ListViewItem to set it as Selected. And lastly, if I can find the ListViewItem and set it to be Selected, won't that fire my SelectionChanged event each time I set a ListViewItem to be Selected?

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