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  • Master Data Management – A Foundation for Big Data Analysis

    - by Manouj Tahiliani
    While Master Data Management has crossed the proverbial chasm and is on its way to becoming mainstream, businesses are being hammered by a new megatrend called Big Data. Big Data is characterized by massive volumes, its high frequency, the variety of less structured data sources such as email, sensors, smart meters, social networks, and Weblogs, and the need to analyze vast amounts of data to determine value to improve upon management decisions. Businesses that have embraced MDM to get a single, enriched and unified view of Master data by resolving semantic discrepancies and augmenting the explicit master data information from within the enterprise with implicit data from outside the enterprise like social profiles will have a leg up in embracing Big Data solutions. This is especially true for large and medium-sized businesses in industries like Retail, Communications, Financial Services, etc that would find it very challenging to get comprehensive analytical coverage and derive long-term success without resolving the limitations of the heterogeneous topology that leads to disparate, fragmented and incomplete master data. For analytical success from Big Data or in other words ROI from Big Data Investments, businesses need to acquire, organize and analyze the deluge of data to make better decisions. There will need to be a coexistence of structured and unstructured data and to maintain a tight link between the two to extract maximum insights. MDM is the catalyst that helps maintain that tight linkage by providing an understanding about the identity, characteristics of Persons, Companies, Products, Suppliers, etc. associated with the Big Data and thereby help accelerate ROI. In my next post I will discuss about patterns for co-existing Big Data Solutions and MDM. Feel free to provide comments and thoughts on above as well as Integration or Architectural patterns.

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  • What's the best way to expose a Model object in a ViewModel?

    - by Angel
    In a WPF MVVM application, I exposed my model object into my viewModel by creating an instance of Model class (which cause dependency) into ViewModel. Instead of creating separate VM properties, I wrap the Model properties inside my ViewModel Property. My model is just an entity framework generated proxy class: public partial class TblProduct { public TblProduct() { this.TblPurchaseDetails = new HashSet<TblPurchaseDetail>(); this.TblPurchaseOrderDetails = new HashSet<TblPurchaseOrderDetail>(); this.TblSalesInvoiceDetails = new HashSet<TblSalesInvoiceDetail>(); this.TblSalesOrderDetails = new HashSet<TblSalesOrderDetail>(); } public int ProductId { get; set; } public string ProductCode { get; set; } public string ProductName { get; set; } public int CategoryId { get; set; } public string Color { get; set; } public Nullable<decimal> PurchaseRate { get; set; } public Nullable<decimal> SalesRate { get; set; } public string ImagePath { get; set; } public bool IsActive { get; set; } public virtual TblCompany TblCompany { get; set; } public virtual TblProductCategory TblProductCategory { get; set; } public virtual TblUser TblUser { get; set; } public virtual ICollection<TblPurchaseDetail> TblPurchaseDetails { get; set; } public virtual ICollection<TblPurchaseOrderDetail> TblPurchaseOrderDetails { get; set; } public virtual ICollection<TblSalesInvoiceDetail> TblSalesInvoiceDetails { get; set; } public virtual ICollection<TblSalesOrderDetail> TblSalesOrderDetails { get; set; } } Here is my ViewModel: public class ProductViewModel : WorkspaceViewModel { #region Constructor public ProductViewModel() { StartApp(); } #endregion //Constructor #region Properties private IProductDataService _dataService; public IProductDataService DataService { get { if (_dataService == null) { if (IsInDesignMode) { _dataService = new ProductDataServiceMock(); } else { _dataService = new ProductDataService(); } } return _dataService; } } //Get and set Model object private TblProduct _product; public TblProduct Product { get { return _product ?? (_product = new TblProduct()); } set { _product = value; } } #region Public Properties public int ProductId { get { return Product.ProductId; } set { if (Product.ProductId == value) { return; } Product.ProductId = value; RaisePropertyChanged("ProductId"); } } public string ProductName { get { return Product.ProductName; } set { if (Product.ProductName == value) { return; } Product.ProductName = value; RaisePropertyChanged(() => ProductName); } } private ObservableCollection<TblProduct> _productRecords; public ObservableCollection<TblProduct> ProductRecords { get { return _productRecords; } set { _productRecords = value; RaisePropertyChanged("ProductRecords"); } } //Selected Product private TblProduct _selectedProduct; public TblProduct SelectedProduct { get { return _selectedProduct; } set { _selectedProduct = value; if (_selectedProduct != null) { this.ProductId = _selectedProduct.ProductId; this.ProductCode = _selectedProduct.ProductCode; } RaisePropertyChanged("SelectedProduct"); } } #endregion //Public Properties #endregion // Properties #region Commands private ICommand _newCommand; public ICommand NewCommand { get { if (_newCommand == null) { _newCommand = new RelayCommand(() => ResetAll()); } return _newCommand; } } private ICommand _saveCommand; public ICommand SaveCommand { get { if (_saveCommand == null) { _saveCommand = new RelayCommand(() => Save()); } return _saveCommand; } } private ICommand _deleteCommand; public ICommand DeleteCommand { get { if (_deleteCommand == null) { _deleteCommand = new RelayCommand(() => Delete()); } return _deleteCommand; } } #endregion //Commands #region Methods private void StartApp() { LoadProductCollection(); } private void LoadProductCollection() { var q = DataService.GetAllProducts(); this.ProductRecords = new ObservableCollection<TblProduct>(q); } private void Save() { if (SelectedOperateMode == OperateModeEnum.OperateMode.New) { //Pass the Model object into Dataservice for save DataService.SaveProduct(this.Product); } else if (SelectedOperateMode == OperateModeEnum.OperateMode.Edit) { //Pass the Model object into Dataservice for Update DataService.UpdateProduct(this.Product); } ResetAll(); LoadProductCollection(); } #endregion //Methods } Here is my Service class: class ProductDataService:IProductDataService { /// <summary> /// Context object of Entity Framework model /// </summary> private MaizeEntities Context { get; set; } public ProductDataService() { Context = new MaizeEntities(); } public IEnumerable<TblProduct> GetAllProducts() { using(var context=new R_MaizeEntities()) { var q = from p in context.TblProducts where p.IsDel == false select p; return new ObservableCollection<TblProduct>(q); } } public void SaveProduct(TblProduct _product) { using(var context=new R_MaizeEntities()) { _product.LastModUserId = GlobalObjects.LoggedUserID; _product.LastModDttm = DateTime.Now; _product.CompanyId = GlobalObjects.CompanyID; context.TblProducts.Add(_product); context.SaveChanges(); } } public void UpdateProduct(TblProduct _product) { using (var context = new R_MaizeEntities()) { context.TblProducts.Attach(_product); context.Entry(_product).State = EntityState.Modified; _product.LastModUserId = GlobalObjects.LoggedUserID; _product.LastModDttm = DateTime.Now; _product.CompanyId = GlobalObjects.CompanyID; context.SaveChanges(); } } public void DeleteProduct(int _productId) { using (var context = new R_MaizeEntities()) { var product = (from c in context.TblProducts where c.ProductId == _productId select c).First(); product.LastModUserId = GlobalObjects.LoggedUserID; product.LastModDttm = DateTime.Now; product.IsDel = true; context.SaveChanges(); } } } I exposed my model object in my viewModel by creating an instance of it using new keyword, also I instantiated my DataService class in VM. I know this will cause a strong dependency. So: What's the best way to expose a Model object in a ViewModel? What's the best way to use DataService in VM?

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  • MVVM- Expose Model object in ViewModel

    - by Angel
    I have a wpf MVVM application , I exposed my model object into my viewModel by creating an instance of Model class (which cause dependency) into ViewModel , and instead of creating seperate VM properties , I wrap the Model properties inside my ViewModel Property. My model is just an entity framework generated proxy classes. Here is my Model class : public partial class TblProduct { public TblProduct() { this.TblPurchaseDetails = new HashSet<TblPurchaseDetail>(); this.TblPurchaseOrderDetails = new HashSet<TblPurchaseOrderDetail>(); this.TblSalesInvoiceDetails = new HashSet<TblSalesInvoiceDetail>(); this.TblSalesOrderDetails = new HashSet<TblSalesOrderDetail>(); } public int ProductId { get; set; } public string ProductCode { get; set; } public string ProductName { get; set; } public int CategoryId { get; set; } public string Color { get; set; } public Nullable<decimal> PurchaseRate { get; set; } public Nullable<decimal> SalesRate { get; set; } public string ImagePath { get; set; } public bool IsActive { get; set; } public virtual TblCompany TblCompany { get; set; } public virtual TblProductCategory TblProductCategory { get; set; } public virtual TblUser TblUser { get; set; } public virtual ICollection<TblPurchaseDetail> TblPurchaseDetails { get; set; } public virtual ICollection<TblPurchaseOrderDetail> TblPurchaseOrderDetails { get; set; } public virtual ICollection<TblSalesInvoiceDetail> TblSalesInvoiceDetails { get; set; } public virtual ICollection<TblSalesOrderDetail> TblSalesOrderDetails { get; set; } } Here is my ViewModel , public class ProductViewModel : WorkspaceViewModel { #region Constructor public ProductViewModel() { StartApp(); } #endregion //Constructor #region Properties private IProductDataService _dataService; public IProductDataService DataService { get { if (_dataService == null) { if (IsInDesignMode) { _dataService = new ProductDataServiceMock(); } else { _dataService = new ProductDataService(); } } return _dataService; } } //Get and set Model object private TblProduct _product; public TblProduct Product { get { return _product ?? (_product = new TblProduct()); } set { _product = value; } } #region Public Properties public int ProductId { get { return Product.ProductId; } set { if (Product.ProductId == value) { return; } Product.ProductId = value; RaisePropertyChanged("ProductId"); } } public string ProductName { get { return Product.ProductName; } set { if (Product.ProductName == value) { return; } Product.ProductName = value; RaisePropertyChanged(() => ProductName); } } private ObservableCollection<TblProduct> _productRecords; public ObservableCollection<TblProduct> ProductRecords { get { return _productRecords; } set { _productRecords = value; RaisePropertyChanged("ProductRecords"); } } //Selected Product private TblProduct _selectedProduct; public TblProduct SelectedProduct { get { return _selectedProduct; } set { _selectedProduct = value; if (_selectedProduct != null) { this.ProductId = _selectedProduct.ProductId; this.ProductCode = _selectedProduct.ProductCode; } RaisePropertyChanged("SelectedProduct"); } } #endregion //Public Properties #endregion // Properties #region Commands private ICommand _newCommand; public ICommand NewCommand { get { if (_newCommand == null) { _newCommand = new RelayCommand(() => ResetAll()); } return _newCommand; } } private ICommand _saveCommand; public ICommand SaveCommand { get { if (_saveCommand == null) { _saveCommand = new RelayCommand(() => Save()); } return _saveCommand; } } private ICommand _deleteCommand; public ICommand DeleteCommand { get { if (_deleteCommand == null) { _deleteCommand = new RelayCommand(() => Delete()); } return _deleteCommand; } } #endregion //Commands #region Methods private void StartApp() { LoadProductCollection(); } private void LoadProductCollection() { var q = DataService.GetAllProducts(); this.ProductRecords = new ObservableCollection<TblProduct>(q); } private void Save() { if (SelectedOperateMode == OperateModeEnum.OperateMode.New) { //Pass the Model object into Dataservice for save DataService.SaveProduct(this.Product); } else if (SelectedOperateMode == OperateModeEnum.OperateMode.Edit) { //Pass the Model object into Dataservice for Update DataService.UpdateProduct(this.Product); } ResetAll(); LoadProductCollection(); } #endregion //Methods } Here is my Service class: class ProductDataService:IProductDataService { /// <summary> /// Context object of Entity Framework model /// </summary> private MaizeEntities Context { get; set; } public ProductDataService() { Context = new MaizeEntities(); } public IEnumerable<TblProduct> GetAllProducts() { using(var context=new R_MaizeEntities()) { var q = from p in context.TblProducts where p.IsDel == false select p; return new ObservableCollection<TblProduct>(q); } } public void SaveProduct(TblProduct _product) { using(var context=new R_MaizeEntities()) { _product.LastModUserId = GlobalObjects.LoggedUserID; _product.LastModDttm = DateTime.Now; _product.CompanyId = GlobalObjects.CompanyID; context.TblProducts.Add(_product); context.SaveChanges(); } } public void UpdateProduct(TblProduct _product) { using (var context = new R_MaizeEntities()) { context.TblProducts.Attach(_product); context.Entry(_product).State = EntityState.Modified; _product.LastModUserId = GlobalObjects.LoggedUserID; _product.LastModDttm = DateTime.Now; _product.CompanyId = GlobalObjects.CompanyID; context.SaveChanges(); } } public void DeleteProduct(int _productId) { using (var context = new R_MaizeEntities()) { var product = (from c in context.TblProducts where c.ProductId == _productId select c).First(); product.LastModUserId = GlobalObjects.LoggedUserID; product.LastModDttm = DateTime.Now; product.IsDel = true; context.SaveChanges(); } } } I exposed my model object in my viewModel by creating an instance of it using new keyword, also I instantiated my DataService class in VM, I know this will cause a strong dependency. So , 1- Whats the best way to expose Model object in ViewModel ? 2- Whats the best way to use DataService in VM ?

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  • Common Service Host for Windows Communication Foundation

    After having to write new instance providers, host factories and service behaviors for almost every new WCF project; I decided to write a simple reusable component for WCF and dependency injection and put it on codeplex so that I never had to write that again.The idea is simple, when creating service hosts you more often [...]...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Silverlight Commands Hacks: Passing EventArgs as CommandParameter to DelegateCommand triggered by Ev

    - by brainbox
    Today I've tried to find a way how to pass EventArgs as CommandParameter to DelegateCommand triggered by EventTrigger. By reverse engineering of default InvokeCommandAction I find that blend team just ignores event args.To resolve this issue I have created my own action for triggering delegate commands.public sealed class InvokeDelegateCommandAction : TriggerAction<DependencyObject>{    /// <summary>    ///     /// </summary>    public static readonly DependencyProperty CommandParameterProperty =        DependencyProperty.Register("CommandParameter", typeof(object), typeof(InvokeDelegateCommandAction), null);    /// <summary>    ///     /// </summary>    public static readonly DependencyProperty CommandProperty = DependencyProperty.Register(        "Command", typeof(ICommand), typeof(InvokeDelegateCommandAction), null);    /// <summary>    ///     /// </summary>    public static readonly DependencyProperty InvokeParameterProperty = DependencyProperty.Register(        "InvokeParameter", typeof(object), typeof(InvokeDelegateCommandAction), null);    private string commandName;    /// <summary>    ///     /// </summary>    public object InvokeParameter    {        get        {            return this.GetValue(InvokeParameterProperty);        }        set        {            this.SetValue(InvokeParameterProperty, value);        }    }    /// <summary>    ///     /// </summary>    public ICommand Command    {        get        {            return (ICommand)this.GetValue(CommandProperty);        }        set        {            this.SetValue(CommandProperty, value);        }    }    /// <summary>    ///     /// </summary>    public string CommandName    {        get        {            return this.commandName;        }        set        {            if (this.CommandName != value)            {                this.commandName = value;            }        }    }    /// <summary>    ///     /// </summary>    public object CommandParameter    {        get        {            return this.GetValue(CommandParameterProperty);        }        set        {            this.SetValue(CommandParameterProperty, value);        }    }    /// <summary>    ///     /// </summary>    /// <param name="parameter"></param>    protected override void Invoke(object parameter)    {        this.InvokeParameter = parameter;                if (this.AssociatedObject != null)        {            ICommand command = this.ResolveCommand();            if ((command != null) && command.CanExecute(this.CommandParameter))            {                command.Execute(this.CommandParameter);            }        }    }    private ICommand ResolveCommand()    {        ICommand command = null;        if (this.Command != null)        {            return this.Command;        }        var frameworkElement = this.AssociatedObject as FrameworkElement;        if (frameworkElement != null)        {            object dataContext = frameworkElement.DataContext;            if (dataContext != null)            {                PropertyInfo commandPropertyInfo = dataContext                    .GetType()                    .GetProperties(BindingFlags.Public | BindingFlags.Instance)                    .FirstOrDefault(                        p =>                        typeof(ICommand).IsAssignableFrom(p.PropertyType) &&                        string.Equals(p.Name, this.CommandName, StringComparison.Ordinal)                    );                if (commandPropertyInfo != null)                {                    command = (ICommand)commandPropertyInfo.GetValue(dataContext, null);                }            }        }        return command;    }}Example:<ComboBox>    <ComboBoxItem Content="Foo option 1" />    <ComboBoxItem Content="Foo option 2" />    <ComboBoxItem Content="Foo option 3" />    <Interactivity:Interaction.Triggers>        <Interactivity:EventTrigger EventName="SelectionChanged" >            <Presentation:InvokeDelegateCommandAction                 Command="{Binding SubmitFormCommand}"                CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=InvokeParameter}" />        </Interactivity:EventTrigger>    </Interactivity:Interaction.Triggers>                </ComboBox>BTW: InvokeCommanAction CommandName property are trying to find command in properties of view. It very strange, because in MVVM pattern command should be in viewmodel supplied to datacontext.

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  • Are there scenarios where the ViewModel needs to invoke methods on the View w.r.t. MVVM in WPF?

    - by Gishu
    As per the pattern, the ViewModel exposes Properties(with change notification) and Commands (to notify the VM of user actions) that the View binds to. The only communication that flows from the VM to the View is the property change notifications (so that the View can refresh itself with updated data). In MVP or PresentationModel form of the pattern (if I'm not mistaken), the View implements a plain vanilla interface (consisting of methods, properties and/or events). With MVVM, it feels methods on the IView have been outlawed (along with IView itself). One scenario I could think of was to set the focus to a certain control in the View. (When the user does ActionX, the focus should immediately be set to FieldY). In MVP, I'd write this as IView.ActivateField(NameConstant), which the presenter or PM would invoke. In MVVM, this seems to be a fringe case that needs a workaround / little bit of code-behind. The VM implements an ActiveField Property, which it sets to NameConstant. The view picks up the change notification event and in a code-behind event handler, activates the Name control. Is the above just an exception to the norm? Or are there other such scenarios, where the VM needs to invoke a method on the View ?

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  • SharePoint 2010 – SQL Server has an unsupported version 10.0.2531.0

    - by Jeff Widmer
    I am trying to perform a database attach upgrade to SharePoint Foundation 2010. At this point I am trying to attach the content database to a Web application by using Windows Powershell: Mount-SPContentDatabase -Name <DatabaseName> -DatabaseServer <ServerName> -WebApplication <URL> [-Updateuserexperience] I am following the directions from this TechNet article: Attach databases and upgrade to SharePoint Foundation 2010.  When I go to mount the content database I am receiving this error: Mount-SPContentDatabase : Could not connect to [DATABASE_SERVER] using integrated security: SQL server at [DATABASE_SERVER] has an unsupported version 10.0.2531.0. Please refer to “http://go.microsoft.com/fwlink/?LinkId=165761” for information on the minimum required SQL Server versions and how to download them. At first this did not make sense because the default SharePoint Foundation 2010 website was running just fine.  But then I realized that the default SharePoint Foundation site runs off of SQL Server Express and that I had just installed SQL Server Web Edition (since the database is greater than 4GB) and restored the database to this version of SQL Server. Checking the documentation link above I see that SharePoint Server 2010 requires a 64-bit edition of SQL Server with the minimum required SQL Server versions as follows: SQL Server 2008 Express Edition Service Pack 1, version number 10.0.2531 SQL Server 2005 Service Pack 3 cumulative update package 3, version number 9.00.4220.00 SQL Server 2008 Service Pack 1 cumulative update package 2, version number 10.00.2714.00 The version of SQL Server 2008 Web Edition with Service Pack 1 (the version I installed on this machine) is 10.0.2531.0. SELECT @@VERSION: Microsoft SQL Server 2008 (SP1) - 10.0.2531.0 (X64)   Mar 29 2009 10:11:52   Copyright (c) 1988-2008 Microsoft Corporation  Web Edition (64-bit) on Windows NT 6.1 <X64> (Build 7600: ) (VM) But I had to read the article several times since the minimum version number for SQL Server Express is 10.0.2531.0.  At first I thought I was good with the version of SQL Server 2008 Web that I had installed, also 10.0.2531.0.  But then I read further to see that there is a cumulative update (hotfix) for SQL Server 2008 SP1 (NOT the Express edition) that is required for SharePoint 2010 and will bump the version number to 10.0.2714.00. So the solution was to install the Cumulative update package 2 for SQL Server 2008 Service Pack 1 on my SQL Server 2008 Web Edition to allow SharePoint 2010 to work with SQL Server 2008 (other than the SQL Server 2008 Express version). SELECT @@VERSION (After installing Cumulative update package 2): Microsoft SQL Server 2008 (SP1) - 10.0.2714.0 (X64)   May 14 2009 16:08:52   Copyright (c) 1988-2008 Microsoft Corporation  Web Edition (64-bit) on Windows NT 6.1 <X64> (Build 7600: ) (VM)

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  • Using MVVM, how to pass SelectedItems of a XamDataGrid as parameter to the Command raised by the Co

    - by saddaypally
    Hi, I'm trying to pass the item on XamDataGrid on which I do a mouse right click to open a ContextMenu, which raises a Command in my ViewModel. Somehow the method that the Command calls is not reachable in debug mode. This is the snipped from the view <ig:XamDataGrid DataSource="{Binding DrdResults}" Height="700" Width="600"> <ig:XamDataGrid.ContextMenu> <ContextMenu DataContext="{Binding RelativeSource={RelativeSource Mode=Self}, Path=PlacementTarget.DataContext}" AllowDrop="True" Name="cmAudit"> <MenuItem Header="View History" Command="{Binding ViewTradeHistory}" CommandParameter="{Binding Path=SelectedItems}"> </MenuItem> </ContextMenu> </ig:XamDataGrid.ContextMenu> <ig:XamDataGrid.FieldSettings> <ig:FieldSettings AllowFixing="NearOrFar" AllowEdit="False" Width="auto" Height="auto" /> </ig:XamDataGrid.FieldSettings> </ig:XamDataGrid> My code in the corresponding ViewModel for this View is as follows public WPF.ICommand ViewTradeHistory { get { if (_viewTradeHistory == null) { _viewTradeHistory = new DelegateCommand( (object SelectedItems) = { this.OpenTradeHistory(SelectedItems); }); } return _viewTradeHistory; } } And lastly the actual method that gets called by the Command is as below private void OpenTradeHistory(object records) { DataPresenterBase.SelectedItemHolder auditRecords = (DataPresenterBase.SelectedItemHolder)records; // Do something with the auditRecords now. } I'm not sure what am I doing incorrectly here. Any help will be very much appreciated. Thanks, Shravan

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  • WPF MVVM UserControl Binding "Container", dispose to avoid memory leak.

    - by user178657
    For simplicity. I have a window, with a bindable usercontrol <UserControl Content="{Binding Path = BindingControl, UpdateSourceTrigger=PropertyChanged}"> I have two user controls, ControlA, and ControlB, Both UserControls have their own Datacontext ViewModel, ControlAViewModel and ControlBViewModel. Both ControlAViewModel and ControlBViewModel inh. from a "ViewModelBase" public abstract class ViewModelBase : DependencyObject, INotifyPropertyChanged, IDisposable........ Main window was added to IoC... To set the property of the Bindable UC, i do ComponentRepository.Resolve<MainViewWindow>().Bindingcontrol= new ControlA; ControlA, in its Datacontext, creates a DispatcherTimer, to do "somestuff".. Later on., I need to navigate elsewhere, so the other usercontrol is loaded into the container ComponentRepository.Resolve<MainViewWindow>().Bindingcontrol= new ControlB If i put a break point in the "someStuff" that was in ControlA's datacontext. The DispatcherTimer is still running... i.e. loading a new usercontrol into the bindable Usercontrol on mainwindow does not dispose/close/GC the DispatcherTimer that was created in the DataContext View Model... Ive looked around, and as stated by others, dispose doesnt get called because its not supposed to... :) Not all my usercontrols have DispatcherTimer, just a few that need to do some sort of "read and refresh" updates./. Should i track these DispatcherTimer objects in the ViewModelBase that all Usercontrols inh. and manually stop/dispose them everytime a new usercontrol is loaded? Is there a better way?

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  • How do you handle 'SelectedItemChanged' events in a MVVM ViewModel?

    - by Travis
    I have some logic that depends upon two properties being set, as it executes when both properties have a value. For example: private void DoCalc() { if (string.IsNullOrEmpty(Property1) || string.IsNullOrEmpty(Property2)) return; Property3 = Property1 + " " + Property2; } That code would need to be executed every time Property1 or Property2 changed, but I'm having trouble figuring out how to do it in a stylistically acceptable manner. Here are the choices as I see them: 1) Call method from ViewModel I don't have a problem with this conceptually, as the logic is still in the ViewModel - I'm not a 'No code-behind' nazi. However, the 'trigger' logic (when either property changes) is still in the UI layer, which I don't love. The codebehind would look like this: void ComboBox_Property1_SelectedItemChanged(object sender, RoutedEventArgs e) { viewModel.DoCalc(); } 2) Call method from Property Setter This approach seems the most 'pure', but it also seems ugly, as if the logic is hidden. It would look like this: public string Property1 { get {return property1;} set { if (property1 != value) { property1 = value; NotifyPropertyChanged("Property1"); DoCalc(); } } } 3) Hook into the PropertyChanged event I'm now thinking this might be the right approach, but it feels weird to hook into the property changed event in the implementing viewmodel. It would look something like this: public ViewModel() { this.PropertyChanged += new PropertyChangedEventHandler(ViewModel_PropertyChanged); } void ViewModel_PropertyChanged(object sender, PropertyChangedEventArgs e) { if (e.PropertyName == "Property1" || e.PropertyName == "Property2") { DoCalc(); } } So, my question is, if you were browsing through some source code with that requirement, which approach would you prefer to see implemented (and why?). Thanks for any input.

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  • I got MVVM 3-Level-Master-Detail Switchting working but with CRUD operations now everything seems st

    - by msfanboy
    Hello, I have 1 UserControl (SchoolclassAdministration.xaml) that is datatemplated with 1 ViewModel (SchoolclassAdministrationViewModel) I have 3 Models and 3 ViewModels in that scenario. Those 3 ViewModels must reflect the requirements of the View. The requirements are 3 "Areas" on the left side and 2 "Areas" on the right side. 3: SchoolclassFormular PupilFormular SubjectFormular Those have all Buttons for Add/Delete 2: PupilsDataGrid SubjectsDataGrid The Master-Detail scenario is between the: SchoolclassFormular = PupilsDataGrid = SubjectsDataGrid The switching of the ViewModelCollections work! My Problem scenario is this: The DataContext is on the SchoolclassAdministrationViewModel what is the ViewModel containing the AllSchoolclassesViewModel ObservableCollection bound to the SchoolclassAdministration.xaml UserControl. My SchoolclassViewModel,PupilViewModel and SubjectViewModel has all Properties, Commands(Add/Delete). My Question: How can I set these 3 ViewModels as DataContext to my ONE SchoolclassAdministration.xaml UserControl I have? Before you answer... putting every ViewModel(schoolclass,pupil,subject) in its own UserControl will not help me because then the Master-Detail switching can NOT work anymore. Every related ViewModels need to be put in a related/ONE UserControl. OK now I can`t wait for an answer because that scenario is driving me nuts for weeks.

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  • WPF/MVVM: How can I use several CollectionView`s for aggregated entities ?

    - by msfanboy
    Hello, I have a Customer with Orders and those have products. Everything aggregated with collections of type ObservableCollection. All 3 collections are bound to a datagrid/combobox. I can only make the root collection (ObservableCollection Customers{ get;set;} ) passing to a CollectionView so I can move the current customer within the combobox. But how can I move around the current Order in the datagrid? How to pass the selected Orders to another CollectionView ? Does all this maybe not work?

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  • MVVM/WPF: Button is not disabled although the CanExecute says return value is FALSE ??

    - by msfanboy
    Hello, I have a detach and attach button with Command="..." bound to my ViewModel. Although I have only 1 selected pupil but have NOT selected a subject the detach button is not disabled, the attach button is ??? public RelayCommand AttachdSubjecstCommand { get { return _attachSubjectsCommand ?? (_attachSubjectsCommand = new RelayCommand(() => AttachSubjects(), () => CanAttachSubjects)); } } public RelayCommand DetachSubjectsCommand { get { return _detachSubjectsCommand ?? (_detachSubjectsCommand = new RelayCommand(() => DetachSubjects(), () => CanDetachSubjects)); } }

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  • MVVM/WPF: Using a ObservableCollection<T> as a list in a domain model, is that good/bad ?

    - by msfanboy
    I have aggregated models like Customer:Order:Product. As my View is bound to the BillingViewModel which has a Property Customers of type ObservableCollection and ONE customer in this collection has a "list" of orders named ObservableCollection and ONE order in this collection has a "list" of products named ObservableCollection Well I need the ObservableCollection`s for databinding but should a domain model really have a ObservableCollection ? normally it has a List or IEnumerable ! Is this bad habit or having side effects?

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  • mvvm-light: Should we merge Cleanup methods in locator?

    - by mark smith
    Hi there, when creating a new ViewModel within the locator class using the snippet it creates a Cleanup Method but there is already one available from the Main so hence an error.... Should we merge them all?? Or should we be renaming the method to Cleanup[Name of viewmodel] for example. I am a little confused here Another question i would like to ask is regards to the naming conventions. I tried to follow the naming convention used with "MAIN"... hence i have CreateLogin, ClearLogin, Login (non static property for binding) etc etc.. Would it not be better to use CreateLoginViewModel, ClearLoginViewModel etc?? Just curious Thanks

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  • Where do I define dependency properties shared by the detail views in a master-detail MVVM WPF scena

    - by absence
    I can think of two ways to implement dependency properties that are shared between the detail views: Store them in the master view model and add data bindings to the detail view models when they are created, and bind to them in the detail view. Don't store them in the view models at all, and use FindAncestor to bind directly to properties of the master view instead. What are the pros and cons of each, and are there other/better options?

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  • MVVM-Light: The target "RunCodeAnalysis" does not exist in the project when i do build??

    - by mark smith
    Hi there, Just built myself a mvvmlight app and if i press f5 TO COMPILE and run all works ok, it displays the wpf window but if i do a BUILD i get an error Error 1 The target "RunCodeAnalysis" does not exist in the project. I am using the visual studio 2010 professional version RTM The only thing i see strange is the target framework which is set to .NET framework 4 client profile Anybody know why this happens??

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  • How can I model the data in a multi-language data editor in WPF with MVVM?

    - by Patrick Szalapski
    Are there any good practices to follow when designing a model/ViewModel to represent data in an app that will view/edit that data in multiple languages? Our top-level class--let's call it Course--contains several collection properties, say Books and TopicsCovered, which each might have a collection property among its data. For example, the data needs to represent course1.Books.First().Title in different languages, and course1.TopicsCovered.First().Name in different languages. We want a app that can edit any of the data for one given course in any of the available languages--as well as edit non-language-specific data, perhaps the Author of a Book (i.e. course1.Books.First().Author). We are having trouble figuring out how best to set up the model to enable binding in the XAML view. For example, do we replace (in the single-language model) each String with a collection of LanguageSpecificString instances? So to get the author in the current language: course1.Books.First().Author.Where(Function(a) a.Language = CurrentLanguage).SingleOrDefault If we do that, we cannot easily bind to any value in one given language, only to the collection of language values such as in an ItemsControl. <TextBox Text={Binding Author.???} /> <!-- no way to bind to the current language author --> Do we replace the top-level Course class with a collection of language-specific Courses? So to get the author in the current language: course1.GetLanguage(CurrentLanguage).Books.First.Author If we do that, we can only easily work with one language at a time; we might want a view to show one language and let the user edit the other. <TextBox Text={Binding Author} /> <!-- good --> <TextBlock Text={Binding ??? } /> <!-- no way to bind to the other language author --> Also, that has the disadvantage of not representing language-neutral data as such; every property (such as Author) would seem to be in multiple languages. Even non-string properties would be in multiple languages. Is there an option in between those two? Is there another way that we aren't thinking of? I realize this is somewhat vague, but it would seem to be a somewhat common problem to design for. Note: This is not a question about providing a multilingual UI, but rather about actually editing multi-language data in a flexible way.

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  • WPF/MVVM: Reshaping/Binding data on a DataGrid to a PivotGrid layout ?

    - by msfanboy
    Hello, I do not want to use 3rd party controls because I would have to buy a suite for justing using one control... So is there any chance I can arrange 3 entities: Subject, Grade and Pupil in that way on a simple DataGrid to show Pivot data like: ...........Math....Sports.... M.Kramer...A.......C......... B.Jonson...D.......A......... Does the binding for example work on the RowHeader with properties of a custom object/entity ? And would sorting destroy the whole relations between the entities ? You ever tried to do something like that?

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