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POWhy is WPF ComboBox item not updating?
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copied!<p>I am not understanding why in my following example the "Billing Model" combobox doesn't display the property BillingModel.BillingModelDescription when the textbox does. After selection of a client, i want the combobox to display the current billng model description, but it stays blank. The textbox bound to the same thing does show the description. I have a collection of possible models as the ItemsSource, which is working fine. How do i update the Billing Model combobox upon selection of a client?</p> <p>Here's the XAML:</p> <pre><code><Window x:Class="WpfApplication7.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <StackPanel> <StackPanel Orientation="Horizontal"> <Label Content="Client"/> <ComboBox ItemsSource="{Binding AllClientData}" DisplayMemberPath="EmployerStr" SelectedItem="{Binding SelectedClient}" Width="300"/> </StackPanel> <StackPanel Orientation="Horizontal"> <Label Content="Billing Model:"/> <ComboBox ItemsSource="{Binding AllBillingModels}" DisplayMemberPath="BillingModelDescription" SelectedItem="{Binding SelectedClient.BillingModel}" Width="300"/> </StackPanel> <StackPanel Orientation="Horizontal"> <Label Content="Billing Model" /> <TextBox Text="{Binding SelectedClient.BillingModel.BillingModelDescription}" Width="200"/> </StackPanel> </StackPanel> </code></pre> <p></p> <p>And the code-behind (this is just an example, I am using MVVM etc in the full app, but this serves my puurpose to illustrate the issue):</p> <pre><code>public partial class MainWindow : Window, INotifyPropertyChanged { public MainWindow() { AllClientData = new ObservableCollection<ClientRate>(); AllBillingModels = new ObservableCollection<BillingModelType>(); ClientRate uno = new ClientRate(); uno.BillingModel = new BillingModelType(); uno.BillingModel.BillingModelID = 3; uno.BillingModel.BillingModelDescription = "Free"; uno.ID = 01; uno.EmployerName = "Employer1"; ClientRate dos = new ClientRate(); dos.BillingModel = new BillingModelType(); dos.BillingModel.BillingModelID = 2; dos.BillingModel.BillingModelDescription = "Variable"; dos.ID = 02; dos.EmployerName = "Employer2"; ClientRate tre = new ClientRate(); tre.BillingModel = new BillingModelType(); tre.BillingModel.BillingModelID = 1; tre.BillingModel.BillingModelDescription = "Flat"; tre.ID = 01; tre.EmployerName = "Employer3"; AllClientData.Add(uno); AllClientData.Add(dos); AllClientData.Add(tre); BillingModelType one = new BillingModelType(); one.BillingModelID = 1; one.BillingModelDescription = "Flat"; BillingModelType two = new BillingModelType(); two.BillingModelID = 2; two.BillingModelDescription = "Variable"; BillingModelType three = new BillingModelType(); three.BillingModelID = 3; three.BillingModelDescription = "Free"; AllBillingModels.Add(one); AllBillingModels.Add(two); AllBillingModels.Add(three); InitializeComponent(); this.DataContext = this; } private ObservableCollection<ClientRate> _allClientData; public ObservableCollection<ClientRate> AllClientData { get { return _allClientData; } set { if (_allClientData != value) { _allClientData = value; FirePropertyChanged("AllClientData"); } } } private ClientRate _selectedClient; /// <summary> /// Gets/Sets Global SelectedClient object /// </summary> public ClientRate SelectedClient { get { return _selectedClient; } set { if (_selectedClient != value) { _selectedClient = value; FirePropertyChanged("SelectedClient"); } } } //private BillingModelType _selectedBillingModel; //public BillingModelType SelectedBillingModel //{ // get // { // return _selectedBillingModel; // } // set // { // if (_selectedBillingModel != value) // { // _selectedBillingModel = value; // FirePropertyChanged("SelectedBillingModel"); // } // } //} private ObservableCollection<BillingModelType> _allBillingModels; /// <summary> /// Holds all possible billing model types /// </summary> public ObservableCollection<BillingModelType> AllBillingModels { get { return _allBillingModels; } set { if (_allBillingModels != value) { _allBillingModels = value; FirePropertyChanged("AllBillingModels"); } } } public event PropertyChangedEventHandler PropertyChanged; protected void FirePropertyChanged(string propertyName) { if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } public class BillingModelType { /// <summary> /// Billing Model ID /// </summary> public int? BillingModelID { get; set; } /// <summary> /// Billing Model Description /// </summary> public string BillingModelDescription { get; set; } } public class ClientRate : INotifyPropertyChanged { /// <summary> /// Employer name with Employer ID in parentheses /// </summary> public string EmployerStr { get { return EmployerName + " (" + ID + ")"; } } /// <summary> /// Employer ID /// </summary> public int? ID { get; set; } private string _EmployerName; /// <summary> /// Employer Official Name /// </summary> public string EmployerName { get { return _EmployerName; } set { if (_EmployerName != value) { _EmployerName = value; FirePropertyChanged("EmployerName"); } } } private BillingModelType _billingModel; /// <summary> /// Rate Type ID and Description /// </summary> public BillingModelType BillingModel { get { return _billingModel; } set { if (_billingModel != value) { _billingModel = value; FirePropertyChanged("BillingModel"); } } } public event PropertyChangedEventHandler PropertyChanged; protected void FirePropertyChanged(string propertyName) { if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } </code></pre>

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