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  • How to Prevent PostBack Event Handler from Firing

    - by user331744
    I have a custom class (ServerSideValidator.vb) that validates user input on server side (it doesn't use any of the .NET built in validators, therefore Page.Validate() is not an option for me). I am calling the Validate() method on page.IsPostback event and the class performs without any problem My issue is, when validation fails (returns false), I want to stop the postback event handler from firing, but load the page along with all the controls and user-input values in them. If I do, Response.End(), the page comes up blank. I can programmatically instruct the page to go to the previous page (original form before postback), but it loses all user-inputs. I thought of creating a global boolean variable in the page code behind file and check the value before performing any postback method, but this approach takes away from my plan to provide all functionalities inside the class itself. The page object is being referenced to ServerSideValidator. Seems like all the postback related properties/variables I come across inside Page class are 'Readonly' and I can't assign value(s) to control/prevent postback event from firing. Any idiea on how I can accomplish this? Please let me know if you need further details

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  • Why won't my Setup Project Perform my Custom Registration Process

    - by Jordan S
    I am trying to write an Setup Project/Installer for a class library driver that I wrote in C# using Visual Studio 2008. The driver project has a section of code that looks like this... [ComRegisterFunction] public static void RegisterASCOM(Type t) { Trace.WriteLine("Registration Started."); DoRegistration(true); } In the driver project Properties - "Assembly Information" I have set checked the box that says Make COM-Visible = true. I added a Setup Project to the solution in VS, added the output dll from the driver project so that it installs on the target machine and set the Register property of the dll to "vsdraCOM". So, my understanding is that when the installer runs it SHOULD execute the methods of the dll that are marked with [COMRegisterFunction]. Using SysInternals Debug View I can monitor when the above code snippet is hit by watching for the "Registration started" text to show up in the window. When I build the solution, I can see the text show up so I know the driver is registering properly. The problem is that when I run the installer, I don't think it is doing the registration bit. I see nothing show up in Debug View. And if i try to access my driver via another application I get an error saying it "Cannot create ActiveX object". Why does the registration not occur during the install process? The driver does register for COM but it does NOT call my custom registration method. Does anyone have and suggestions of what I could be missing? Is there another way I can debug this? (I can provide more code if anyone want's to take a look!!)

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  • Block Cascade Json Serealize?

    - by CrazyJoe
    I have this Class: public class User { public string id{ get; set; } public string name{ get; set; } public string password { get; set; } public string email { get; set; } public bool is_broker { get; set; } public string branch_id { get; set; } public string created_at{get; set;} public string updated_at{get; set;} public UserGroup UserGroup {get;set;} public UserAddress UserAddress { get; set; } public List<UserContact> UserContact {get; set;} public User() { UserGroup = new UserGroup(); UserAddress = new UserAddress(); UserContact = new List<UserContact>(); } } I like to Serealize Only properties , how i block serealization of UserGroup, UserAdress, asn UserContact??? This is my Serealization function: public static string Serealize<T>(T obj) { System.Runtime.Serialization.Json.DataContractJsonSerializer serializer = new System.Runtime.Serialization.Json.DataContractJsonSerializer(obj.GetType()); MemoryStream ms = new MemoryStream(); serializer.WriteObject(ms, obj); return Encoding.UTF8.GetString(ms.ToArray(), 0,(int)ms.Length); }

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  • Abstracting the interpretation of MVC checkboxes values received by the FormsCollection object

    - by Simon_Weaver
    In ASP.NET MVC a checkbox is generated by the HtmlHelper code here: <%= Html.CheckBox("List_" + mailingList.Key, true) %> as this HTML: <input id="List_NEW_PRODUCTS" name="List_NEW_PRODUCTS" type="checkbox" value="true" /> <input name="List_NEW_PRODUCTS" type="hidden" value="false" /> In case you're wondering why is there an extra hidden field? - then read this. Its definitely a solution that makes you first think 'hmmmmm' but then you realize its a pretty elegant one. The problem I have is when I'm trying to parse the data on the backend. Well its not so much of a problem as a concern if anything in future were to change in the framework. If I'm using the built in binding everything is great - its all done for me. But in my case I'm dynamically generating checkboxes with unknown names and no corresponding properties in my model. So i end up having to write code like this : if (forms["List_RETAIL_NOTIFICATION"] == "true,false") { } or this: if (forms.GetValues("List_RETAIL_NOTIFICATION")[0] == "true") { } Both of which i still look at and cringe - especially since theres no guarantee this will always be the return value. I'm wondering if theres a way to access the layer of abstraction used by the model binders - or if I'm stuck with my controller 'knowing' this much about HTTP POST hacks. Yes I'm maybe being a little picky - but perhaps theres a better clever way using the model binders that I can employ to read dynamically created checkbox parameters. In addition i was hoping this this post might help others searcheing for : "true,false". Even though I knew why it does this I just forgot and it took me a little while to realize 'duh'. FYI: I tried another few things, and this is what I found : forms["List_RETAIL_NOTIFICATION"] evaluates to "true,false" forms.GetValues("List_RETAIL_NOTIFICATION")[0] evaluates to "true" (forms.GetValue("List_RETAIL_NOTIFICATION").RawValue as string[])[0] evaluates to "true" forms.GetValues("List_RETAIL_NOTIFICATION").FirstOrDefault() evaluates to "true"

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  • How can I debug a session

    - by Organ Grinding Monkey
    I have been asked to work of a very large web application and deploy it. The problem that I'm facing here is that when I deploy the application and more that 1 user logs into the system, the sessions seem to cross over i.e: Person A logs in and works on the site, all good. When person B logs in, person A will then be logged in as person B as well. I have been asked to work of a very large web application and deploy it. The problem that I'm facing here is that when I deploy the application and more that 1 user logs into the system, the sessions seem to cross over i.e: Person A logs in and works on the site, all good. When person B logs in, person A will then be logged in as person B as well. If anyone has experienced this behaviour before and can steer me in the right direction, that would be first prize, Second prize would be to show me how I can debug this situation so that I can find out where the problem is and fix it. Some information about the application. From what I've been told and what I've seen within the app is that it started as a .Net 1.1 application and got upgraded to .Net 2 and that's why the log in system was done the way it is. (The application is huge and now complete and that's why I cant rewrite the whole user authentication process, it will just take to long and I don't know what effect it might have) All the Logged in User information is stored in properties that have been added in the Global.asax.vb file. (could this be the problem?) Any help here would be greatly appreciated

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  • How do I get 2-way data binding to work for nested asp.net Repeater controls

    - by jimblanchard
    I have the following (trimmed) markup: <asp:Repeater ID="CostCategoryRepeater" runat="server"> <ItemTemplate> <div class="costCategory"> <asp:Repeater ID="CostRepeater" runat="server" DataSource='<%# Eval("Costs")%>'> <ItemTemplate> <tr class="oddCostRows"> <td class="costItemTextRight"><span><%# Eval("Variance", "{0:c0}")%></span></td> <td class="costItemTextRight"><input id="SupplementAmount" class="costEntryRight" type="text" value='<%# Bind("SupplementAmount")%>' runat="server" /></td> </tr> </ItemTemplate> </asp:Repeater> </div> </ItemTemplate> </asp:Repeater> The outer repeater's DataSource is set in the code-beside. I've snipped them, but there are Eval statements that wire up to the properties in the outer Repeater. Anyway, one of the fields in the inner Repeater needs to be a Bind instead of an Eval, as I want to get the values that the user types in. The SupplementAmount input element correctly receives it's value when the page loads, but on the other side, when I inspect the contents of the Costs List when the form posts back, the changes the user made aren't present. Thanks.

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  • What's the correct way to pass parameters from VBScript to COM interface implemented in C#?

    - by nopopem
    I'm trying to expose a fairly simple C# class to COM which should be usable from VBScript (among others). Some objects need to be created via COM calls and will be used in furter calls later on. The definition of the exposed classes and interfaces looks like this: namespace Test { [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)] public interface IComInterface { IFoo CreateFoo(); void UseFoo(int x, IFoo f); } [ClassInterface(ClassInterfaceType.None)] public sealed class CComInterface : IComInterface { public CComInterface() {} public IFoo CreateFoo() { return new Foo(); } public void UseFoo(int x, IFoo f) { f.Bar(); } } [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)] public interface IFoo { void Bar(); } [ClassInterface(ClassInterfaceType.None)] public class Foo : IFoo { internal Foo() {} public void Bar() {} } } The simplest thinkable COM client in VBScript does this: Dim ci Set ci = WScript.CreateObject("Test.CComInterface") Dim foo Set foo = ci.CreateFoo foo.Bar ci.UseFoo 0, foo While the call to Bar succeeds, calling UseFoo fails with "Error 5: invalid procedure call or invalid argument" The generated IDL seems ok to me: dispinterface IComInterface { properties: methods: [id(0x60020003)] IFoo* CreateFoo(); [id(0x60020004)] void UseFoo( [in] long x, [in] IFoo* f); }; The vbs call succeeds when I wrap the second parameter in parentheses like this: ci.UseFoo 0, (foo) As far as I understand (I'm no VBScript expert however) this forces the reference to foo to be passed by value, i.e. a copy of the reference is being made. How can I change the interface so that it can be called with the foo reference directly? Since this will be a public interface used by customers I don't like the idea of having to explain why all the objects created need to be passed back in an extra pair of parentheses...

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  • threading and getting COM port of attached phone

    - by I__
    i have the following code: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } public class ThreadWork { public static void DoWork() { } } private void Form1_Load(object sender, EventArgs e) { ThreadStart myThreadDelegate = new ThreadStart(ThreadWork.DoWork); Thread myThread = new Thread(myThreadDelegate); myThread.Start(); // Begin communications serialPort1.Open(); serialPort1.Write("AT+CMGF=1\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CNMI=2,2\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CSCA=\"+4790002100\"\r\n"); //Thread.Sleep(500); } private void serialPort1_DataReceived_1(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) { string response = serialPort1.ReadLine(); this.BeginInvoke(new MethodInvoker(() => textBox1.AppendText(response + "\r\n"))); } } } what i am trying to do is send AT COMMANDS to my phone which is attached to the computer through USB how do i know how to configure the properties of the serial port? (like which COM is the phone on [it's attached through USB], what about baudrate and databits?) when i run the program nothing really happens, i would like to send AT COMMANDS to my phone and the textbox is there to receive the response from my phone this is my first time using threads. am i using them correctly? what is the purpose of it in the current example? is it to just have a delay between send a response? what am i doing wrong?

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  • Is there any reason why jQuery Sortable would work in IE/Chrome but not Firefox?

    - by DNS
    I have a fairly straightforward list of horizontally floated items, like this: <div class="my-widget-container"> <div class="my-widget-column">...</div> ... </div> Both the container and each column have a fixed width, set using jQuery's .width(). The container is position: relative and the column is float: left and overflow: hidden. Not sure if any other styles/properties are relevant. When I apply a jQuery-UI sortable to this, the result is exactly what I'd expect in Chome 8 and IE 8; the columns can be dragged around to change their order. But in Firefox 3.6 I can click an item and drag to create a new sort-helper, yet the actual sort never happens; the real item's position in the DOM never changes. I dug around a little in Sortable, and added a debug print to _intersectsWithPointer. Whenever the drag helper moves, Sortable runs through its list of elements and uses this method to determine whether the drag helper has passed over one. What I saw was that item.left had the same value for all my columns, which is obviously not correct, and probably the source of the problem. It looks like all columns had a left position corresponding to that of the first column. I'm using jQuery 1.4.3 and jQuery UI Sortable 1.8. Those aren't the very latest versions, but they're pretty recent, and I don't see anything in the Sortable release notes that indicates any such problem has been fixed. Does anyone know what might be happening here, or have any ideas for further debugging?

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  • Actionscript: How Can I Know When The Source Property Of An Image Is Completely Updated

    - by Joshua
    var I:Image=new Image(); I.source='C:\\Abc.png'; var H:int=I.height; H is always Zero! I am presuming this is because the image hasn't finished reading the png file off the disk yet. What event can I monitor to know when it's width and height will have the right values? The 'Complete' event only seems to work for DOWNLOADED images. The 'Render' event happens EVERY FRAME. The (undocumented?) 'sourceChanged', happens as soon as source changes, and has the same problem! What event do I watch that will let me know when the image's width and height properties will have valid values? Or is there some Synchronous version of I.source='xxx.png', that I don't know about? P.S. Yes, I know I shouldn't use "C:\" in an Air Program. This was just for illustrative purposes, so that you won't suggest I use "Complete", which never even seems to fire when the file indicated by source is local.

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  • How to check at runtime if a class implements certain interface?

    - by mare
    Let's say I have some content classes like Page, TabGroup, Tab, etc. Certain of those will be implementing my IWidgetContainer interface - it means they will geet an additional field named ContainedItems from the interface and some methods for manipulating this field. Now I need to reflect the fact that some class implements this interface by rendering out some special custom controls in my ASP.NET MVC Views (like jQuery Add/Remove/Move/Reorder buttons). For instance, TabGroup will implement IWidgetContainer because it will contain tabs but a tab will not implement it because it won't have the ability to contain anything. So I have to somehow check in my view, when I render my content objects (The problem is, I use my base class as strong type in my view not concrete classes), whether it implements IWidgetContainer. How is that possible or have I completely missed something? To rephrase the question, how do you reflect some special properties of a class (like interface implementation) in the UI in general (not necessarily ASP.NET MVC)? Here's my code so far: [DataContract] public class ContentClass { [DataMember] public string Slug; [DataMember] public string Title; [DataMember] protected ContentType Type; } [DataContract] public class Group : ContentClass, IWidgetContainer { public Group() { Type = ContentType.TabGroup; } public ContentList ContainedItems { get; set; } public void AddContent(ContentListItem toAdd) { throw new NotImplementedException(); } public void RemoveContent(ContentListItem toRemove) { throw new NotImplementedException(); } } [DataContract] public class GroupElement : ContentClass { public GroupElement() { Type = ContentType.Tab; } } Interface: interface IWidgetContainer { [DataMember] ContentList ContainedItems { get; set; } void AddContent(ContentListItem toAdd); void RemoveContent(ContentListItem toRemove); }

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  • How does asp.net MVC remember my false values on postback?

    - by Michel
    Hi, This is working, but how??? I have a controller action for a post: [AcceptVerbs(HttpVerbs.Post )] public ActionResult Edit(Person person) { bool isvalid = ModelState.IsValid; etc. The Person object has a property BirthDate, type DateTime. When i enter some invalid data in the form, say 'blabla' which is obvious not a valid Datetime, it fills all the (other) Person properties with the correct data and the BirthDate property with a new blank DateTime. The bool isvalid has the value 'false'. So far so good. Then i do this: return View(p); and in the view i have this: <%= Html.TextBox("BirthDate", String.Format("{0:g}", Model.BirthDate)) %> <%= Html.ValidationMessage("BirthDate", "*") %> Ant there it comes: i EXPECTED the model to contain the new, blank DateTime because i didn't put any new data in. Second, when the View displays something, it must be a DateTime, because Model.BirthDate can't hold anything but a DateTime. But to my surprise, it shows a textbox with the 'blabla' value! (and the red * behind it) Which ofcourse is nice because the user can seee what he typed wrong, but how can that (blabla)string be transferred to the View in a DateTime field?

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  • Custom Image Button and Radio/Toggle Button from Common Base Class

    - by Wonko the Sane
    Hi All, I would like to create a set of custom controls that are basically image buttons (it's a little more complex than that, but that's the underlying effect I'm going for) that I've seen a few different examples for. However, I would like to further extend that to also allow radio/toggle buttons. What I'd like to do is have a common abstract class called ImageButtonBase that has default implementations for ImageSource and Text, etc. That makes a regular ImageButton implementation pretty easy. The issue I am having is creating the RadioButton flavor of it. As I see it, there are at least three options: It would be easy to create something that derives from RadioButton, but then I can't use the abstract class I've created. I could change the abstract class to an interface, but then I lose the abstract implementations, and will in fact have duplication of code. I could derive from my abstract class, and re-implement the RadioButton-type properties and events (IsChecked, GroupName, etc.), but that certainly doesn't seem like a great idea. Note: I have seen http://stackoverflow.com/questions/2362641/how-to-get-a-group-of-toggle-buttons-to-act-like-radio-buttons-in-wpf, but what I want to do is a little more complex. I'm just wondering if anybody has an example of an implementation, or something that might be adapted to this kind of scenario. I can see pros and cons of each of the ideas above, but each comes with potential pitfalls. Thanks, wTs

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  • How might a C# programmer approach writing a solution in javascript?

    - by Ben McCormack
    UPDATE: Perhaps this wasn't clear from my original post, but I'm mainly interested in knowing a best practice for how to structure javascript code while building a solution, not simply learning how to use APIs (though that is certainly important). I need to add functionality to a web site and our team has decided to approach the solution using a web service that receives a call from a JSON-formatted AJAX request from within the web site. The web service has been created and works great. Now I have been tasked with writing the javascript/html side of the solution. If I were solving this problem in C#, I would create separate classes for formatting the request, handling the AJAX request/response, parsing the response, and finally inserting the response somehow into the DOM. I would build properties and methods appropriately into each class, doing my best to separate functionality and structure where appropriate. However, I have to solve this problem in javascript. Firstly, how could I approach my solution in javascript in the way I would approach it from C# as described above? Or more importantly, what's a better way to approach structuring code in javascript? Any advice or links to helpful material on the web would be greatly appreciated. NOTE: Though perhaps not immediately relevant to this question, it may be worth noting that we will be using jQuery in our solution.

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  • Should I be using Expression Blend to design really dynamic UIs?

    - by Robert Rossney
    My company's product is, at its core, a framework for developing metadata-driven UIs. I don't know how to characterize it less succinctly than that, and hope I won't need to for purposes of this question, but we'll see. I've been trying to come up to speed on WPF, and have been building UI prototypes here and there, and recently I decided to see if I could use Expression Blend to help with the design of these UIs. And I'm pretty mystified at this point. It appears to me as though Expresssion Blend is designed with the expectation that you already know all of the objects that are going to be present in the UI at design time. But our program generates these object dynamically at runtime. For instance, a data row might be presented in a horizontal StackPanel containing alternating TextBlocks (for captions) and TextBoxes (for data fields). The number of these objects depends on metadata about the number of columns in the data row. I can, pretty readily, write code that runs through a metadata record and populates a StackPanel dynamically, setting up the binding of all of the controls to properties in either the data or metadata. (A TextBox's Width might be bound to metadata, while its Text is bound to data.) But I can't even begin to figure out how to do something like this in Expression Blend. I can manually create all these controls, so that I have a set of controls that I can apply styles to and work out the visual design of the app, but it's really a pain to do this. I can write code that goes through my data model and emits XAML for all these controls, I suppose, and then copy and paste it. But I'm going to feel really stupid if it turns out there a way to do this sort of thing in Expression Blend and I've dropped back and punted because I'm too dim to figure out the right way to think of it. Is this enough information for someone to try formulating an answer?

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  • Unable to diligently close the excel process running in memory

    - by NewAutoUser
    I have developed a VB.Net code for retrieving data from excel file .I load this data in one form and update it back in excel after making necessary modifications in data. This complete flow works fine but most of the times I have observed that even if I close the form; the already loaded excel process does not get closed properly. I tried all possible ways to close it but could not be able to resolve the issue. Find below code which I am using for connecting to excel and let me know if any other approach I may need to follow to resolve this issue. Note: I do not want to kill the excel process as it will kill other instances of the excel Dim connectionString As String connectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" & ExcelFilePath & "; Extended Properties=excel 8.0; Persist Security Info=False" excelSheetConnection = New ADODB.Connection If excelSheetConnection.State = 1 Then excelSheetConnection.Close() excelSheetConnection.Open(connectionString) objRsExcelSheet = New ADODB.Recordset If objRsExcelSheet.State = 1 Then objRsExcelSheet.Close() Try If TestID = "" Then objRsExcelSheet.Open("Select * from [" & ActiveSheet & "$]", excelSheetConnection, 1, 1) Else objRsExcelSheet.Open("Select Test_ID,Test_Description,Expected_Result,Type,UI_Element,Action,Data,Risk from [" & ActiveSheet & "$] WHERE TEST_Id LIKE '" & TestID & ".%'", excelSheetConnection, 1, 1) End If getExcelData = objRsExcelSheet Catch errObj As System.Runtime.InteropServices.COMException MsgBox(errObj.Message, , errObj.Source) Return Nothing End Try excelSheetConnection = Nothing objRsExcelSheet = Nothing

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  • Indirect property notification

    - by Carlo
    Hello, this question might look a little trivial, but it might not be. I'm just wondering which of the following two cases is better for indirect property notification, or perhaps there is an even better way. The scenario: I have two properties, the first one is an object called HoldingObject, the second one is a boolean called IsHoldingObject, which is false if HoldingObject == null, otherwise it's true. I'm just wondering what is the best notification mechanism for IsHoldingObject: Case (A) - Notify IsHoldingObject changed from the HoldingObject proeperty: public class NotifyingClass1 : INotifyPropertyChanged { private object _holdingObject; public object HoldingObject { get { return _holdingObject; } set { if (_holdingObject != value) { _holdingObject = value; NotifyPropertyChanged("HoldingObject"); // Notify from the property that is being checked NotifyPropertyChanged("IsHoldingObject"); } } } public bool IsHoldingObject { get { return this.HoldingObject == null; } } #region INotifyPropertyChanged Members public event PropertyChangedEventHandler PropertyChanged; private void NotifyPropertyChanged(string propertyName) { if (this.PropertyChanged != null) this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } #endregion } Case (B) - Notify IsHoldingObject changed from the IsHoldingObject directly, by setting it to false or true from HoldingObject property: public class NotifyingClass2 : INotifyPropertyChanged { private object _holdingObject; public object HoldingObject { get { return _holdingObject; } set { if (_holdingObject != value) { _holdingObject = value; NotifyPropertyChanged("HoldingObject"); // 1) Set the property here this.IsHoldingObject = _holdingObject != null; } } } private bool _isHoldingObject; public bool IsHoldingObject { get { return _isHoldingObject; } set { if (_isHoldingObject != value) { _isHoldingObject = value; // 2) Notify directly from the property NotifyPropertyChanged("IsHoldingObject"); } } } #region INotifyPropertyChanged Members public event PropertyChangedEventHandler PropertyChanged; private void NotifyPropertyChanged(string propertyName) { if (this.PropertyChanged != null) this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } #endregion } I personally lean to the first one because it requires less code, but I'm not sure how recommendable it is to do that. Let me know if there is another (better) way. Thanks!

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  • java.lang.ClassNotFoundException in Netbeans. 5 hours to fix

    - by user1304281
    Hi I've got to submit an interpreter assignment tonight and all of a sudden it stopped working! It was working yesterday but now when I try to create a class instance at runtime I get classnotfoundexception. My project has no libraries or dependencies, I've written everything myself. I've googled around and it seems to be an issue with classpath but I've had no luck fooling with the project properties on netbeans. Here's some code: package interpreter; import interpreter.bytecode.ByteCode; import java.io.*; import java.lang.reflect.*; class ByteCodeLoader { //.... String codeClass = CodeTable.CodeTable.get(args[0]); ByteCode bytecode = (ByteCode)(Class.forName("interpreter.bytecode."+codeClass).newInstance()); //this throws exception } all of my ByteCodes are contained within a subpackage of interpreter called interpreter.bytecode. I'll be watching this thread so I can answer/clarify any questions immediately. Thanks for your time!

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  • Advice on Linq to SQL mapping object design

    - by fearofawhackplanet
    I hope the title and following text are clear, I'm not very familiar with the correct terms so please correct me if I get anything wrong. I'm using Linq ORM for the first time and am wondering how to address the following. Say I have two DB tables: User ---- Id Name Phone ----- Id UserId Model The Linq code generator produces a bunch of entity classes. I then write my own classes and interfaces which wrap these Linq classes: class DatabaseUser : IUser { public DatabaseUser(User user) { _user = user; } public Guid Id { get { return _user.Id; } } ... etc } so far so good. Now it's easy enough to find a users phones from Phones.Where(p => p.User = user) but surely comsumers of the API shouldn't need to be writing their own Linq queries to get at data, so I should wrap this query in a function or property somewhere. So the question is, in this example, would you add a Phones property to IUser or not? In other words, should my interface specifically be modelling my database objects (in which case Phones doesn't belong in IUser), or are they actually simply providing a set of functions and properties which are conceptually associated with a User (in which case it does)? There seems drawbacks to both views, but I'm wondering if there is a standard approach to the problem. Or just any general words of wisdom you could share. My first thought was to use extension methods but in fact that doesn't work in this case.

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  • Concrete examples of state sharing between multiple viewmodels (WPF MVVM)

    - by JohnMetta
    I have a WPF/Entity Framework (4.0) project with many objects. I'd like to build the application so that that I can have object selection state shared across viewmodels. For Example: We have Cars, Drivers, Passengers, and Cargo classes. We also have UserControls for CarList, DriverList, etc. and editor windows for CarEditor, DriverEditor, etc. Furthermore, we have viewmodels for all of these (CarListViewModel, DriverListViewModel, CargoEditorViewModel, etc). This all composes a dockable interface where the user can have multiple object lists, editors, and viewers open. What I want is a concrete code example of how to wireup multiple viewmodels so that selecting a car in the CarList will cause that car to go live in the CarEditorView, but also be selected in any other view for which the context is valid (such as a DriverByCarView- or just DriverList if there is a filter predicate). There are a number of suggestions and discussions based on this question. The two methods that seem to dominate are: 3018307: Discusses state sharing by mentioning a messaging subsystem 1159035: Discusses state sharing by using an enclosing viewmodel Is one of these approaches better than the other? Does anyone have a concrete example of either/both of these methods in the form of a write-up or small code project? I'm still learning WPF, so pointers to entry points for reading API fundamentals are appreciated, but looking at code examples is where I usually go. Thanks In case anyone is interested, here are some other similar discussions: 3816961: Discusses returning multiple viewmodels depending on object type (i.e. a collection of arbitrary types adhering to a specific interface) 1928130: Discusses whether it is a good idea to aggregate viewmodels as properties of other viewmodels (e.g. a MainWindow viewmodel composed of panel viewmodels) 1120061: Essentially discusses whether to have use a viewmodel-per-model strategy or a viewmodel-per-view-element strategy. 4244222: Discusses whether or not to nest the viewmodels when using a nested object hierarchy. 4429708: Discusses sharing collections between viewmodels directly, but doesn't go into detail. List item: Discusses managing multiple selections within a single viewmodel.

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  • Using block around a static/singleton resource reference

    - by byte
    This is interesting (to me anyway), and I'd like to see if anyone has a good answer and explanation for this behavior. Say you have a singleton database object (or static database object), and you have it stored in a class Foo. public class Foo { public static SqlConnection DBConn = new SqlConnection(ConfigurationManager.ConnectionStrings["BAR"].ConnectionString); } Then, lets say that you are cognizant of the usefulness of calling and disposing your connection (pretend for this example that its a one-time use for purposes of illustration). So you decide to use a 'using' block to take care of the Dispose() call. using (SqlConnection conn = Foo.DBConn) { conn.Open(); using (SqlCommand cmd = new SqlCommand()) { cmd.Connection = conn; cmd.CommandType = System.Data.CommandType.StoredProcedure; cmd.CommandText = "SP_YOUR_PROC"; cmd.ExecuteNonQuery(); } conn.Close(); } This fails, with an error stating that the "ConnectionString property is not initialized". It's not an issue with pulling the connection string from the app.config/web.config. When you investigate in a debug session you see that Foo.DBConn is not null, but contains empty properties. Why is this?

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  • Is it getting to be time for C# to support compile-time macros?

    - by Robert Rossney
    Thus far, Microsoft's C# team has resisted adding formal compile-time macro capabilities to the language. There are aspects of programming with WPF that seem (to me, at least) to be creating some compelling use cases for macros. Dependency properties, for instance. It would be so nice to just be able to do something like this: [DependencyProperty] public string Foo { get; set; } and have the body of the Foo property and the static FooProperty property be generated automatically at compile time. Or, for another example an attribute like this: [NotifyPropertyChanged] public string Foo { get; set; } that would make the currently-nonexistent preprocessor produce this: private string _Foo; public string Foo { get { return _Foo; } set { _Foo = value; OnPropertyChanged("Foo"); } } You can implement change notification with PostSharp, and really, maybe PostSharp is a better answer to the question. I really don't know. Assuming that you've thought about this more than I have, which if you've thought about it at all you probably have, what do you think? (This is clearly a community wiki question and I've marked it accordingly.)

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  • Create lambda action from function expression

    - by Martin Robins
    It is relatively easy to create a lambda function that will return the value of a property from an object, even including deep properties... Func<Category, string> getCategoryName = new Func<Category, string>(c => c.Name); and this can be called as follows... string categoryName = getCategoryName(this.category); But, given only the resulting function above (or the expression originally used to create the function), can anybody provide an easy way to create the opposing action... Action<Category, string> setCategoryName = new Action<Category, string>((c, s) => c.Name = s); ...that will enable the same property value to be set as follows? setCategoryName(this.category, ""); Note that I am looking for a way to create the action programatically from the function or expression - I hope that I have shown that I already know how to create it manually. I am open to answers that work in both .net 3.5 and 4.0. Thanks.

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  • c# threading and getting COM port of attached phone

    - by I__
    i have the following code: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } public class ThreadWork { public static void DoWork() { } } private void Form1_Load(object sender, EventArgs e) { ThreadStart myThreadDelegate = new ThreadStart(ThreadWork.DoWork); Thread myThread = new Thread(myThreadDelegate); myThread.Start(); // Begin communications serialPort1.Open(); serialPort1.Write("AT+CMGF=1\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CNMI=2,2\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CSCA=\"+4790002100\"\r\n"); //Thread.Sleep(500); } private void serialPort1_DataReceived_1(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) { string response = serialPort1.ReadLine(); this.BeginInvoke(new MethodInvoker(() => textBox1.AppendText(response + "\r\n"))); } } } what i am trying to do is send AT COMMANDS to my phone which is attached to the computer through USB how do i know how to configure the properties of the serial port? (like which COM is the phone on [it's attached through USB], what about baudrate and databits?) when i run the program nothing really happens, i would like to send AT COMMANDS to my phone and the textbox is there to receive the response from my phone this is my first time using threads. am i using them correctly? what is the purpose of it in the current example? is it to just have a delay between send a response? what am i doing wrong?

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  • Any problems with this C++ const reference accessor interface idiom?

    - by mskfisher
    I was converting a struct to a class so I could enforce a setter interface for my variables. I did not want to change all of the instances where the variable was read, though. So I converted this: struct foo_t { int x; float y; }; to this: class foo_t { int _x; float _y; public: foot_t() : x(_x), y(_y) { set(0, 0.0); } const int &x; const float &y; set(int x, float y) { _x = x; _y = y; } }; I'm interested in this because it seems to model C#'s idea of public read-only properties. Compiles fine, and I haven't seen any problems yet. Besides the boilerplate of associating the const references in the constructor, what are the downsides to this method? Any strange aliasing issues? Why haven't I seen this idiom before?

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