Hi I have a problem with binding my data from a collection view model in xaml.
But databinding fails, VisualStudio reports error "no such table: Recipe"
Can any one help me with this problem?
The XAML:
<Page.DataContext>
<vm:RecipeListViewModel />
</Page.DataContext>
<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
<ListView Header="Recipes" x:Name="RecipeList" HorizontalAlignment="Left" Height="512" Margin="156,118,0,0" VerticalAlignment="Top" Width="430" DataContext="{Binding Recipes[0].Recipe_Name}" ItemsSource="{Binding RecipeCollection.Recipe}" />
<Image x:Name="Img" HorizontalAlignment="Left" Height="260" Margin="698,116,0,0" VerticalAlignment="Top" Width="462"/>
<Button Content="Button" HorizontalAlignment="Left" Margin="698,420,0,0" VerticalAlignment="Top" Click="Button_Click_1"/>
</Grid>
The RecipeListViewModel
class RecipeListViewModel : INotifyPropertyChanged
{
ObservableCollection<Recipe> _Recipes;
public ObservableCollection<Recipe> Recipes
{
get { return _Recipes; }
set
{
if (_Recipes != value)
{
PropertyChanged(this, new PropertyChangedEventArgs("Recipes"));
}
}
}
public event PropertyChangedEventHandler PropertyChanged = delegate { };
public RecipeListViewModel()
{
_Recipes = new ObservableCollection<Recipe>();
var dbPath = Path.Combine(Windows.Storage.ApplicationData.Current.LocalFolder.Path, "LCHFData.db");
using (var db = new SQLite.SQLiteConnection(dbPath))
{
var tb = db.Table<Recipe>().ToList<Recipe>();
foreach (Recipe recipe in tb)
{
_Recipes.Add(recipe);
}
}
}
}
The RecipeViewModel:
class RecipeViewModel : INotifyPropertyChanged{
/*
* Class to Display whole recipe object
*/
Recipe _Recipe;
public Recipe Recipe
{
set
{
if (_Recipe != value)
{
_Recipe = value;
PropertyChanged(this, new PropertyChangedEventArgs("Recipe"));
}
}
get { return new Recipe() { Recipe_Name = "boo "}; }
}
public event PropertyChangedEventHandler PropertyChanged = delegate { };
}
Related
I have a ViewModel with all the properties that i will need in every sub ViewModel.
It's the first time i try to split commands and viewmodel to multiple files. Last time everything was in the same ViewModel and it was a pain to work with it. Everything shows up as expected but i want to find a way to pass the same data in every viewmodel.
From my GetOrdersCommand, i want to get the HeaderViewModel.SelectedSource property. I didn't find any way to do it without getting a null return or loosing the property data...
I would like to call my GetOrdersCommand from HeaderView button too.
Any tips how i can achieve this ? Perhaps, my design is not good for what i'm trying to do ?
MainWindow.xaml
<views:HeaderView Grid.Row="0" Grid.Column="1" Grid.ColumnSpan="2" DataContext="{Binding HeaderViewModel}" LoadHeaderViewCommand="{Binding LoadHeaderViewCommand}"/>
<TabControl TabStripPlacement="Bottom" Grid.Row="1" Grid.Column="1" Grid.RowSpan="2" Grid.ColumnSpan="2">
<TabItem Header="General">
</TabItem>
<TabItem Header="Orders">
<views:OrderView DataContext="{Binding OrderViewModel}" GetOrdersCommand="{Binding GetOrdersCommand}"/>
</TabItem>
</TabControl>
HeaderView.xaml
<DockPanel>
<ComboBox DockPanel.Dock="Left" Width="120" Margin="4" VerticalContentAlignment="Center" ItemsSource="{Binding SourceList}" SelectedItem="{Binding SelectedSource}" DisplayMemberPath="SourceName"/>
<Button x:Name="btnTest" HorizontalAlignment="Left" DockPanel.Dock="Left" Margin="4" Content="Test"/>
</DockPanel>
HeaderView.xaml.cs
public partial class OrderView : UserControl
{
public ICommand GetOrdersCommand
{
get { return (ICommand)GetValue(GetOrdersCommandProperty); }
set { SetValue(GetOrdersCommandProperty, value); }
}
public static readonly DependencyProperty GetOrdersCommandProperty =
DependencyProperty.Register("GetOrdersCommand", typeof(ICommand), typeof(OrderView), new PropertyMetadata(null));
public OrderView()
{
InitializeComponent();
}
private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
if (GetOrdersCommand != null)
{
GetOrdersCommand.Execute(this);
}
}
}
MainViewModel.cs
private OrderViewModel orderViewModel;
public OrderViewModel OrderViewModel { get; set; } // Getter, setter with OnPropertyChanged
private HeaderViewModel headerViewModel;
public HeaderViewModel HeaderViewModel { get; set; } // Getter, setter with OnPropertyChanged
public MainViewModel()
{
HeaderViewModel = new HeaderViewModel();
OrderViewModel = new OrderViewModel();
}
HeaderViewModel.cs
public ICommand LoadHeaderViewCommand { get; set; }
public HeaderViewModel()
{
LoadHeaderViewCommand = new LoadHeaderViewCommand(this);
}
GetOrdersCommand.cs
public class GetOrdersCommand : ICommand
{
public event EventHandler CanExecuteChanged;
private readonly OrderViewModel _orderViewModel;
public GetOrdersCommand(OrderViewModel orderViewModel)
{
_orderViewModel = orderViewModel;
}
public bool CanExecute(object parameter)
{
return true;
}
public void Execute(object parameter)
{
/* Build Order List according to HeaderViewModel.SelectedSource */
_orderViewModel.Orders = new ObservableCollection<Order>()
{
new Order { ID = 1, IsReleased = false, Name = "Test1"},
new Order { ID = 2, IsReleased = true, Name = "Test2"},
};
}
}
Thanks guys ! I moved my commands to their owning ViewModel as suggested.
I tried MVVVM Light Tools and found about Messenger Class.
I used it to send my SelectedSource (Combobox from HeaderView) from HeaderViewModel to OrderViewModel. Am i suppose to use Messenger class like that ? I don't know, but it did the trick!!!
I thought about moving GetOrdersCommand to OrderViewModel, binding my button command to OrderViewModel, binding SelectedSource as CommandParameter but i didn't know how i was suppose to RaiseCanExecuteChanged when HeaderViewModel.SelectedSource changed... Any advice?
MainWindow.xaml
<views:HeaderView DataContext="{Binding Source={StaticResource Locator}, Path=HeaderVM}" Grid.Row="0" Grid.Column="1" Grid.ColumnSpan="2"/>
<TabControl TabStripPlacement="Bottom" Grid.Row="1" Grid.Column="1" Grid.RowSpan="2" Grid.ColumnSpan="2">
<TabItem Header="General">
</TabItem>
<TabItem Header="Orders">
<views:OrderView DataContext="{Binding Source={StaticResource Locator}, Path=OrderVM}"/>
</TabItem>
</TabControl>
OrderViewModel.cs
private ObservableCollection<Order> _orders;
public ObservableCollection<Order> Orders
{
get { return _orders; }
set
{
if (_orders != value)
{
_orders = value;
RaisePropertyChanged(nameof(Orders));
}
}
}
public OrderViewModel()
{
Messenger.Default.Register<Source>(this, source => GetOrders(source));
}
private void GetOrders(Source source)
{
if (source.SourceName == "Production")
{
Orders = new ObservableCollection<Order>(){
new Order { ID = 1, IsReleased = false, Name = "Production 1" }
};
}
else
{
Orders = new ObservableCollection<Order>(){
new Order { ID = 2, IsReleased = true, Name = "Test 1" }
};
}
}
Part of HeaderViewModel.cs
private Source _SelectedSource;
public Source SelectedSource
{
get { return _SelectedSource; }
set
{
if (_SelectedSource != value)
{
_SelectedSource = value;
RaisePropertyChanged(nameof(SelectedSource));
GetOrdersCommand.RaiseCanExecuteChanged();
}
}
}
private RelayCommand _GetOrdersCommand;
public RelayCommand GetOrdersCommand
{
get
{
if (_GetOrdersCommand == null)
{
_GetOrdersCommand = new RelayCommand(GetOrders_Execute, GetOrders_CanExecute);
}
return _GetOrdersCommand;
}
}
private void GetOrders_Execute()
{
Messenger.Default.Send(SelectedSource);
}
private bool GetOrders_CanExecute()
{
return SelectedSource != null ? true : false;
}
I have been having this issue and have been trying to figure out for the past few days, I set up a second test project as my first project is too big to try and nail this down. I'm still fairly new to mvvm so I'm still learning. Whenever I try to save a field using Entity it starts complaining the FirstName field is required, I sort of nailed down the issue to being apart of something with the button because whenever I move the button into the same UserControl as the textbox it will save. The TabControl in the MainWindow has a UserControl for each tab and each one has their own respective ViewModel and then the TabControl itself has a ViewModel.
MainWindow
Just contains the button and the tab control
<Window.Resources>
<vm:TabControlViewModel x:Key="tab"/>
</Window.Resources>
<Grid DataContext="{StaticResource tab}">
<TabControl Margin="10"
Width="500"
Height="500">
<TabItem Header="Test Tab 1">
<custom:TabOneUserControl/>
</TabItem>
<TabItem Header="Test Tab 2">
<custom:TabTwoUserControl/>
</TabItem>
</TabControl>
<Button Content="Save"
Width="120"
Height="50"
Margin="1114,604,41,38.5"
Command="{Binding SaveCommand}"/>
</Grid>
TabOneUserControl
Contains a textbox and label
<UserControl.Resources>
<vm:TabOneUserControlViewModel x:Key="vm"/>
</UserControl.Resources>
<Grid DataContext="{StaticResource vm}">
<StackPanel VerticalAlignment="Center">
<Label Content="First Name"
HorizontalAlignment="Center"/>
<TextBox Width="250"
Height="50"
Text="{Binding FirstName, UpdateSourceTrigger=PropertyChanged}"/>
</StackPanel>
</Grid>
</UserControl>
TabTwoUserControl
Contains a textbox and label
<UserControl.Resources>
<vm:TabTwoUserControlViewModel x:Key="vm"/>
</UserControl.Resources>
<Grid DataContext="{StaticResource vm}">
<StackPanel VerticalAlignment="Center">
<Label Content="Last Name"
HorizontalAlignment="Center"/>
<TextBox Width="250"
Height="50"
Text="{Binding LastName, UpdateSourceTrigger=PropertyChanged}"/>
</StackPanel>
</Grid>
</UserControl>
TabControlViewModel
For the tab control
public class TabControlViewModel
{
public SaveCommand SaveCommand { get; set; }
private TabOneUserControlViewModel tabOneUserControl;
private TabTwoUserControlViewModel tabTwoUserControl;
public TabControlViewModel()
{
tabOneUserControl = new TabOneUserControlViewModel();
tabTwoUserControl = new TabTwoUserControlViewModel();
SaveCommand = new SaveCommand(this);
}
public void SaveInformation()
{
using (TestDbEntities test = new TestDbEntities())
{
test.FNs.Add(new FN
{
FirstName = tabOneUserControl.FirstName
});
test.LNs.Add(new LN
{
LastName = tabTwoUserControl.LastName
});
try
{
test.SaveChanges();
Debug.Print("SAVED CHANGES!");
}
catch (DbEntityValidationException ex)
{
foreach (var validationErrors in ex.EntityValidationErrors)
{
foreach (var validationError in validationErrors.ValidationErrors)
{
Trace.TraceInformation(
"Class: {0}, Property: {1}, Error: {2}",
validationErrors.Entry.Entity.GetType().FullName,
validationError.PropertyName,
validationError.ErrorMessage);
}
}
}
}
}
}
TabOneUserControlViewModel
For the first tab user control
public class TabOneUserControlViewModel : INotifyPropertyChanged
{
private string firstName;
public event PropertyChangedEventHandler PropertyChanged;
public string FirstName
{
get { return firstName; }
set
{
firstName = value;
OnPropertyChanged("FirstName");
}
}
public TabOneUserControlViewModel()
{
}
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
}
TabTwoUserControlViewModel
For the second tab user control
public class TabTwoUserControlViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private string lastName;
public string LastName
{
get { return lastName; }
set
{
lastName = value;
OnPropertyChanged("LastName");
}
}
public TabTwoUserControlViewModel()
{
}
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
}
Thanks to everyone in the comments for your suggestions, Nawed's comment nailed it perfectly for what I was doing wrong. Here is the final code changes I made:
TabControlViewModel
Removed the fields and made them into properties
public class TabControlViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public SaveCommand SaveCommand { get; set; }
public TabOneUserControlViewModel TabOneUserControl { get; set; }
public TabTwoUserControlViewModel TabTwoUserControl { get; set; }
public TabControlViewModel()
{
TabOneUserControl = new TabOneUserControlViewModel();
TabTwoUserControl = new TabTwoUserControlViewModel();
SaveCommand = new SaveCommand(this);
}
public void SaveInformation()
{
using (TestDbEntities test = new TestDbEntities())
{
test.FNs.Add(new FN
{
FirstName = TabOneUserControl.FirstName
});
test.LNs.Add(new LN
{
LastName = TabTwoUserControl.LastName
});
try
{
test.SaveChanges();
Debug.Print("SAVED CHANGES!");
}
catch (DbEntityValidationException ex)
{
foreach (var validationErrors in ex.EntityValidationErrors)
{
foreach (var validationError in validationErrors.ValidationErrors)
{
Trace.TraceInformation(
"Class: {0}, Property: {1}, Error: {2}",
validationErrors.Entry.Entity.GetType().FullName,
validationError.PropertyName,
validationError.ErrorMessage);
}
}
}
}
}
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
}
TabOneUserControl
Removed the static resource from the grid and replaced it with a regular binding and then changed the binding in the Text element, this was the same thing I did in the second user control so I will negate posting the second UserControl:
<Grid DataContext="{Binding TabOneUserControl}">
<StackPanel VerticalAlignment="Center">
<Label Content="First Name"
HorizontalAlignment="Center"/>
<TextBox Width="250"
Height="50"
Text="{Binding FirstName, UpdateSourceTrigger=PropertyChanged}"/>
</StackPanel>
</Grid>
I searched in this forum but I was unable to find a solution for my specific scenario.
I`m trying to understand WPF and MVVM and I build a simple WPF for this.
My Data Model is (I Implemented INotifyPropertyChanged here and the constructor initializes all properties):
namespace MyApp.ui.Models
{
public class Server : INotifyPropertyChanged
{
private int id;
public int ID
{
get { return id; }
set { id = value; }
}
private string name;
public string Name
{
get { return name; }
set { name = value; OnPropertyChanged(Name); }
}
private string ipAddress;
public string IPAddress
{
get { return ipAddress; }
set { ipAddress = value; OnPropertyChanged(IPAddress); }
}
public Server(int ServerID, string ServerName, string ServerIpAddress)
{
ID = ServerID;
Name = ServerName;
IPAddress = ServerIpAddress;
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if(handler != null)
{
handler(this, new PropertyChangedEventArgs( propertyName ) );
}
}
}
}
My ViewModel (used by WPF Code Behind):
namespace MyApp.ui.ViewModels
{
public class ServersViewModel
{
private ObservableCollection<Server> server;
public ObservableCollection<Server> Servers
{
get { return server; }
set { server = value; }
}
public ServersViewModel()
{
Servers = new ObservableCollection<Server>
{
new Server(001, "Server001", #"192.168.254.3"),
new Server(002, "Server002", #"100.92.0.200"),
new Server(003, "Server003", #"64.32.0.3"),
new Server(004, "Server004", #"172.10.0.4"),
new Server(005, "Server005", #"165.23.0.233"),
new Server(006, "Server006", #"81.22.22.6"),
new Server(007, "Server007", #"10.10.0.7")
};
}
public void ChangeServerNames()
{
//Before Change
foreach (var item in Servers)
{
MessageBox.Show(item.Name);
}
int count = 1000;
foreach (var item in Servers)
{
item.Name = "Server" + count.ToString();
count += 1000;
}
//After Change
foreach (var item in Servers)
{
MessageBox.Show(item.Name);
}
}
}
}
My WPF Main View (Main Menu) loads a Custom user control (ExplorerView) with the following XAML code (Contains a listbox and each listbox item contains 1 checkbox + image + textblock)
<UserControl x:Class="MyApp.ui.Views.ExplorerView"
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"
xmlns:local="clr-namespace:MyApp.ui.Views"
mc:Ignorable="d"
d:DesignHeight="400" d:DesignWidth="200">
<Grid>
<ListBox ItemsSource="{Binding Servers}" Margin="2">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox VerticalContentAlignment="Center" Margin="4">
<StackPanel Orientation="Horizontal">
<Image Source="/resources/server64.png" Height="30" Margin="4"></Image>
<TextBlock Text="{Binding Name}"
VerticalAlignment="Center" Margin="4"></TextBlock>
</StackPanel>
</CheckBox>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</UserControl>
Finally the MainView Code Behind loads the ServersViewModel so the ExplorerView Control can Bind the data.
namespace MyApp.ui
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public ServersViewModel context { get; set; }
public MainWindow()
{
InitializeComponent();
context = new ServersViewModel();
DataContext = context;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
context.ChangeServerNames();
}
}
}
That said, I have 2 Questions:
1) As you can see, in the MainView I implemented a Button click event that calls into ServersViewModel.ChangeServerNames() Method. The problem is that my TextBlock in ExplorerView Control does not show the updated data.
I ChangeServerNames() I also use a MessageBox to show the Values Before and After the change, and I see that the values are changing, not sure why the ListBox/TextBlock is not updating...!!! (I already tested many other possible solutions, but I can`t get it working...)
2) I read that the CodeBehind in MainView (and all other views) should only contain the InitializeComponent(); and "DataContext = context;" at Maximum...
If that is true, where the Events for button clicks and others should be placed?
Finally the code for the MainWindow XAML:
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:MyApp.ui"
xmlns:Views="clr-namespace:MyApp.ui.Views"
x:Class="MyApp.ui.MainWindow"
mc:Ignorable="d"
Title="Server" MinHeight="720" MinWidth="1024"
Height ="720" Width="1024">
<Grid Margin="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200" />
<ColumnDefinition Width="Auto"/>
<ColumnDefinition />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="41*"/>
<RowDefinition Height="608*"/>
<RowDefinition Height="30"/>
</Grid.RowDefinitions>
<GridSplitter Grid.Column="1" Grid.Row="1"
HorizontalAlignment="Center"
VerticalAlignment="Stretch"
Background="Gray"
ShowsPreview="True"
Width="4" Margin="0,2,0,4"
/>
<Views:MenuView Grid.ColumnSpan="3"/>
<Views:FooterView Grid.Row="2" Grid.ColumnSpan="3" />
<Views:ExplorerView Grid.Column="0" Grid.Row="1" />
<!--Temp Tests-->
<StackPanel Margin="12" Grid.Column="3" Grid.Row="1" Width="Auto" Height="Auto" Orientation="Horizontal" VerticalAlignment="Top" HorizontalAlignment="Left">
<Button Margin="4" Width="120" Height="30" Content="Change Data Test..." Click="Button_Click" />
</StackPanel>
</Grid>
</Window>
Thank you for your time...
Ok, I found the problem...
Instead of
set { name = value; OnPropertyChanged(Name); }
set { ipAddress = value; OnPropertyChanged(IPAddress); }
I was missing the Quotesfor the String argument on method call
The correct form is
set { name = value; OnPropertyChanged("Name"); }
set { ipAddress = value; OnPropertyChanged("IPAddress"); }
Weird that the compiler didn`t throw any error.... The Method
private void OnPropertyChanged(string propertyName)
Is "Asking" for a string as input arg.
AnyWay the best to avoid these errors (that I found) is to write the event like this (The caller supplies it`s own Public Name):
private void OnPropertyChanged([CallerMemberName] String propertyName = "")
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
Now I can do
set { name = value; OnPropertyChanged(); }
set { ipAddress = value; OnPropertyChanged(); }
Thank you.
I have a view model called FieldViewModel:
public class FieldViewModel: INotifyPropertyChanged
{
private Field m_field;
public Field FieldData
{
get { return m_field; }
set
{
m_field = value;
NotifyPropertyChanged("FieldData");
}
}
and the Field class:
public class Field : INotifyPropertyChanged
{
public List<string> SqlTypes
{
get { return Enum.GetNames(typeof(SqlDbType)).ToList(); }
}
private string m_FieldName = null;
public string FieldName
{
get { return m_FieldName; }
set
{
m_FieldName = value;
NotifyPropertyChanged("FieldName");
}
}
private string m_FieldType = null;
public string FieldType
{
get { return m_FieldType; }
set
{
m_FieldType = value;
NotifyPropertyChanged("FieldType");
}
}
private bool m_NullAllow = false;
public bool NullAllow
{
get { return m_NullAllow; }
set
{
m_NullAllow = value;
NotifyPropertyChanged("NullAllowsChecked");
}
}
#region INotifyPropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged(String propertyName = "")
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
}
The Xaml:
<ComboBox ItemsSource="{Binding FieldData.SqlTypes}" SelectionChanged="cmbField_Selected" Width="20" Height="20" Margin="5,5,0,5" VerticalAlignment="Top" HorizontalAlignment="Left"/>
<TextBox Width="120" Height="20" Text="{Binding FieldType}" Margin="0,5" VerticalAlignment="Top" HorizontalAlignment="Left"/>
now in the xaml i want to bind the variables of the Field Class but i can't see them
I tried some thing but nothing works, if i put the variables of the Field Class inside the FieldViewModel it works good.
Thank for your help.
Here is an example which works for me:
<Window x:Class="DataGridExample.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">
<Grid>
<DataGrid x:Name="czesciTable" ItemsSource="{Binding model.list}"
AutoGenerateColumns="False"
CanUserAddRows="False">
<DataGrid.Columns>
<DataGridTemplateColumn>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock Text="{Binding}"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
</Grid>
Viewmodel:
public class ViewModel
{
public Model model { get; set; }
public ViewModel()
{
model = new Model();
}
}
And model:
public class Model
{
public List<String> list { get; set; }
public Model()
{
list = new List<string>();
list.Add("Item1");
list.Add("Item2");
list.Add("Item3");
}
}
Result:
Or ComboBox:
<ComboBox ItemsSource="{Binding model.list}" VerticalAlignment="Top"/>
The code in the question was mainly correct. It was only missing the initialization of the Field Class.
Having some problems displaying strings in a datagrid.
To explain the code: I am binding a collection of Soldiers to a ComboBox. A Soldier has its own collection of weapons.
When I select a specific soldier in the ComboBox, I want that soldier's weapons displayed in the datagrid. I believe I'm binding correctly, but the datagrid always comes up blank. Anybody know what i'm doing wrong?
XAML
<Grid>
<ComboBox x:Name="Character_ComboBox" HorizontalAlignment="Left" VerticalAlignment="Top" Width="328" Height="25">
</ComboBox>
</Grid>
<DataGrid x:Name="Character_items_datagrid" ItemsSource="{Binding ElementName=Character_ComboBox, Path= SelectedItem.Equipment, Mode=OneWay}" Margin="328,0,0,0" Grid.RowSpan="2" >
<DataGrid.Columns>
<DataGridTextColumn Header="Primary" Binding="{Binding Primary, Mode=TwoWay}" FontWeight="Bold" Foreground="Black" Width="0.1*"></DataGridTextColumn>
<DataGridTextColumn Header ="Secondary" Binding="{Binding Secondary, Mode=TwoWay}" Width="0.1*"></DataGridTextColumn>
</DataGrid.Columns>
</DataGrid>
Soldier Class
public class Soldier
{
public string Soldier_Class { get; set; }
public ObservableCollection<Weapons> Equipment { get; set; }
}
Weapons Class
public class Weapons
{
string Primary { get; set; }
string Secondary { get; set; }
public Weapons(string primary, string secondary)
{
this.Primary = primary;
this.Secondary = secondary;
}
}
MainWindow
public ObservableCollection<Soldier> squad_members = new ObservableCollection<Soldier>();
public MainWindow()
{
InitializeComponent();
squad_members.Add(new Soldier() { Soldier_Class = "Assult Soldier", Equipment = new ObservableCollection<Weapons>() { new Weapons("M4 Rifle", "Compact 45 Pistol")}});
squad_members.Add(new Soldier() { Soldier_Class = "SMG Soldier", Equipment = new ObservableCollection<Weapons>() { new Weapons("RPK Machine Gun", "HK Shotgun"), new Weapons("SAW Machine Gun", "Compact 45 Pistol")}});
squad_members.Add(new Soldier() { Soldier_Class = "Juggernaut", Equipment = new ObservableCollection<Weapons>() { new Weapons("MP5", "Bowie Knife") }});
Binding comboBinding = new Binding();
comboBinding.Source = squad_members;
BindingOperations.SetBinding(Character_ComboBox, ComboBox.ItemsSourceProperty, comboBinding);
Character_ComboBox.DisplayMemberPath = "Soldier_Class";
Character_ComboBox.SelectedValuePath = "Soldier_Class";
}
Result:
You need to make properties in the model public for binding to be able to work :
public class Weapons
{
public string Primary { get; set; }
public string Secondary { get; set; }
.....
}
Your DataGrid looks populated with items correctly, just the properties of each item are not correctly displayed in the columns. This is indication that binding engine can't access the item's properties due to it's private accessibility.
Your primary problem is the public access modifier, as har07 wrote.
There are a lot of other things you can improve as well. Implement INotifyPropertyChanged for your classes, so any change to the properties is immediately reflected by the UI. Without compelling reasons, do not create bindings in code. Use a ViewModel to bind to, instead of binding directly to elements like ComboBox.SelectedItem. Set AutoGenerateColumns to false if you want to style your columns (your code would produce four columns). Use Grid.ColumnDefinitions instead of assigning a fixed margin.
Models:
using System.Collections.ObjectModel;
using System.ComponentModel;
namespace WpfApplication1.ViewModels
{
public class SquadViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
private ObservableCollection<Soldier> _squadMembers;
public ObservableCollection<Soldier> SquadMembers { get { return _squadMembers; } set { _squadMembers = value; OnPropertyChanged("SquadMembers"); } }
private Soldier _selectedSoldier;
public Soldier SelectedSoldier { get { return _selectedSoldier; } set { _selectedSoldier = value; OnPropertyChanged("SelectedSoldier"); } }
public SquadViewModel()
{
SquadMembers = new ObservableCollection<Soldier>()
{
new Soldier() { SoldierClass = "Assult Soldier", Equipment = new ObservableCollection<Weapon>() { new Weapon("M4 Rifle", "Compact 45 Pistol") } },
new Soldier() { SoldierClass = "SMG Soldier", Equipment = new ObservableCollection<Weapon>() { new Weapon("RPK Machine Gun", "HK Shotgun"), new Weapon("SAW Machine Gun", "Compact 45 Pistol") } },
new Soldier() { SoldierClass = "Juggernaut", Equipment = new ObservableCollection<Weapon>() { new Weapon("MP5", "Bowie Knife") } }
};
}
}
public class Soldier : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
private string _soldierClass;
public string SoldierClass { get { return _soldierClass; } set { _soldierClass = value; OnPropertyChanged("SoldierClass"); } }
private ObservableCollection<Weapon> _equipment;
public ObservableCollection<Weapon> Equipment { get { return _equipment; } set { _equipment = value; OnPropertyChanged("Equipment"); } }
}
public class Weapon : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
private string _primary;
string Primary { get { return _primary; } set { _primary = value; OnPropertyChanged("Primary"); } }
private string _secondary;
string Secondary { get { return _secondary; } set { _secondary = value; OnPropertyChanged("Secondary"); } }
public Weapon(string primary, string secondary)
{
this.Primary = primary;
this.Secondary = secondary;
}
}
}
Xaml:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="clr-namespace:WpfApplication1.ViewModels"
Title="MainWindow" Height="350" Width="580">
<Window.DataContext>
<vm:SquadViewModel />
</Window.DataContext>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<ComboBox x:Name="CbxCharacter" HorizontalAlignment="Left" VerticalAlignment="Top" Width="328" Height="25"
ItemsSource="{Binding SquadMembers}" SelectedItem="{Binding SelectedSoldier}"
DisplayMemberPath="SoldierClass" SelectedValuePath="SoldierClass"/>
<DataGrid x:Name="DgCharacterItems" ItemsSource="{Binding SelectedSoldier.Equipment, Mode=OneWay}" Grid.Column="1" AutoGenerateColumns="False" >
<DataGrid.Columns>
<DataGridTextColumn Header="Primary" Binding="{Binding Primary, Mode=TwoWay}" FontWeight="Bold" Foreground="Black" Width="*" />
<DataGridTextColumn Header="Secondary" Binding="{Binding Secondary, Mode=TwoWay}" Width="*" />
</DataGrid.Columns>
</DataGrid>
</Grid>
</Window>