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WPF restoring position in the Combobox

There is an Observablecollection Fathers that stores the ID-Firstname-Lastname father. How to make it so that when loading data from the child.lbs file, the ID value that is written in the file under word[4] is selected in the Combobox field? Item values are spelled out using XAML <Combobox "ItemsSource = {Binding Fathers}"/>
That is, so that when the file is loaded, the same values are restored as they were before the shutdown (the so-called Save/Load)
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Father.cs
namespace LabelBase.Models
{
public class Father : INotifyPropertyChanged
{
private int _id;
public int FatherID
{
get => _id;
set
{
_id = value;
OnPropertyChanged();
}
}
private string _firstname;
public string Firstname
{
get => _firstname;
set
{
_firstname = value;
OnPropertyChanged();
}
}
private string _secondname;
public string Secondname
{
get => _secondname;
set
{
_secondname = value;
OnPropertyChanged();
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged([CallerMemberName] string prop = "")
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(prop));
}
}
}
Child.cs
namespace LabelBase.Models
{
public class Child : INotifyPropertyChanged
{
private int _id;
public int ChildID
{
get => _id;
set
{
_id = value;
OnPropertyChanged();
}
}
private string _first;
public string Firstname
{
get => _first;
set
{
_first = value;
OnPropertyChanged();
}
}
private string _second;
public string Secondname
{
get => _second;
set
{
_second = value;
OnPropertyChanged();
}
}
private Father _father;
public Father Father
{
get => _father;
set
{
_father = value;
OnPropertyChanged();
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged([CallerMemberName] string prop = "")
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(prop));
}
}
}
child.lbs contents:
13;Ken;Hollow;83
10;Fill;Kenory;93
father.lbs contents:
83;Frank;Malkov
93;Jack;Miles
MainWindow.xaml:
<Grid>
<TabControl>
<TabItem Header="Save">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Button Grid.Column="0" Content="Save" Margin="100" Height="50" Command="{Binding SaveButton}"/>
<Button Grid.Column="1" Content="Load" Margin="100" Height="50" Command="{Binding LoadButton}"/>
</Grid>
</TabItem>
<TabItem Header="Child">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Grid Margin="5,5,5,50" Grid.Column="0">
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
</Grid.RowDefinitions>
<TextBlock Grid.Column="0" Grid.Row="0" Height="25" Margin="5" Text="{Binding ElementName=ChildGrid, Path=Columns[0].Header, StringFormat={}{0}: }" TextAlignment="Right"/>
<TextBlock Grid.Column="0" Grid.Row="1" Height="25" Margin="5" Text="{Binding ElementName=ChildGrid, Path=Columns[1].Header, StringFormat={}{0}: }" TextAlignment="Right"/>
<TextBlock Grid.Column="0" Grid.Row="2" Height="25" Margin="5" Text="{Binding ElementName=ChildGrid, Path=Columns[2].Header, StringFormat={}{0}: }" TextAlignment="Right"/>
<TextBlock Grid.Column="0" Grid.Row="3" Height="25" Margin="5" Text="{Binding ElementName=ChildGrid, Path=Columns[3].Header, StringFormat={}{0}: }" TextAlignment="Right"/>
<TextBox Grid.Column="1" Grid.Row="0" Height="25" Text="{Binding SelectedChildren.ChildID}" Margin="5"/>
<TextBox Grid.Column="1" Grid.Row="1" Height="25" Text="{Binding SelectedChildren.Firstname}" Margin="5"/>
<TextBox Grid.Column="1" Grid.Row="2" Height="25" Text="{Binding SelectedChildren.Secondname}" Margin="5"/>
<ComboBox Grid.Column="1" Grid.Row="3" Height="25" ItemsSource="{Binding Fathers}" SelectedItem="{Binding SelectedChildren.Father}" Margin="5">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock>
<TextBlock.Text>
<MultiBinding StringFormat="{}{0} {1}">
<Binding Path="Firstname"/>
<Binding Path="Secondname"/>
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
</Grid>
<DataGrid Name="ChildGrid" Grid.Column="1" Margin="0,10,10,10" AutoGenerateColumns="False" ItemsSource="{Binding Children}" SelectedItem="{Binding SelectedChildren}">
<DataGrid.Columns>
<DataGridTextColumn Width="auto" Header="ID" Binding="{Binding ChildID}"/>
<DataGridTextColumn Width="auto" Header="Firstname" Binding="{Binding Firstname}"/>
<DataGridTextColumn Width="auto" Header="Secondname" Binding="{Binding Secondname}"/>
<DataGridTextColumn Width="auto" Header="Father" Binding="{Binding Father.FatherID}"/>
</DataGrid.Columns>
</DataGrid>
<Button Height="25" Margin="10,0,10,20" Content="Add Child" Command="{Binding AddChildButton}" VerticalAlignment="Bottom"/>
</Grid>
</TabItem>
<TabItem Header="Father">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Grid Margin="5,5,5,50" Grid.Column="0">
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
</Grid.RowDefinitions>
<TextBlock Grid.Column="0" Grid.Row="0" Height="25" Margin="5" Text="{Binding ElementName=FatherGrid, Path=Columns[0].Header, StringFormat={}{0}: }" TextAlignment="Right"/>
<TextBlock Grid.Column="0" Grid.Row="1" Height="25" Margin="5" Text="{Binding ElementName=FatherGrid, Path=Columns[1].Header, StringFormat={}{0}: }" TextAlignment="Right"/>
<TextBlock Grid.Column="0" Grid.Row="2" Height="25" Margin="5" Text="{Binding ElementName=FatherGrid, Path=Columns[2].Header, StringFormat={}{0}: }" TextAlignment="Right"/>
<TextBox Grid.Column="1" Grid.Row="0" Height="25" Text="{Binding SelectedFathers.FatherID}" Margin="5"/>
<TextBox Grid.Column="1" Grid.Row="1" Height="25" Text="{Binding SelectedFathers.Firstname}" Margin="5"/>
<TextBox Grid.Column="1" Grid.Row="2" Height="25" Text="{Binding SelectedFathers.Secondname}" Margin="5"/>
</Grid>
<DataGrid Name="FatherGrid" Grid.Column="1" Margin="0,10,10,10" AutoGenerateColumns="False" ItemsSource="{Binding Fathers}" SelectedItem="{Binding SelectedFathers}">
<DataGrid.Columns>
<DataGridTextColumn Width="auto" Header="ID" Binding="{Binding FatherID}"/>
<DataGridTextColumn Width="auto" Header="Firstname" Binding="{Binding Firstname}"/>
<DataGridTextColumn Width="auto" Header="Secondname" Binding="{Binding Secondname}"/>
</DataGrid.Columns>
</DataGrid>
<Button Height="25" Margin="10,0,10,20" Content="Add Father" Command="{Binding AddFatherButton}" VerticalAlignment="Bottom"/>
</Grid>
</TabItem>
</TabControl>
</Grid>
ContextVIew.cs:
using LabelBase.Models;
namespace LabelBase
{
public class ContextView : INotifyPropertyChanged
{
public ObservableCollection<Father> Fathers { get; }
public ObservableCollection<Child> Children { get; }
private Father _selectedFather;
public Father SelectedFathers
{
get => _selectedFather;
set
{
_selectedFather = value;
OnPropertyChanged();
}
}
private RelayCommand _addFatherButton;
public RelayCommand AddFatherButton
{
get
{
return _addFatherButton ?? (_addFatherButton = new RelayCommand(obj =>
{
Father f = new Father();
Random r = new Random();
f.FatherID = r.Next(99);
Fathers.Insert(Fathers.Count, f);
SelectedFathers = f;
}));
}
}
private Child _selectedChild;
public Child SelectedChildren
{
get => _selectedChild;
set
{
_selectedChild = value;
OnPropertyChanged();
}
}
private RelayCommand _addChildButton;
public RelayCommand AddChildButton
{
get
{
return _addChildButton ?? (_addChildButton = new RelayCommand(obj =>
{
Child c = new Child();
Random r = new Random();
c.ChildID = r.Next(99);
Children.Insert(Children.Count, c);
SelectedChildren = c;
}));
}
}
private RelayCommand _save;
public RelayCommand SaveButton
{
get
{
return _save ?? (_save = new RelayCommand(obj =>
{
StreamWriter swChild = new StreamWriter($"{AppDomain.CurrentDomain.BaseDirectory}/save/child.lbs", false);
StreamWriter swFather = new StreamWriter($"{AppDomain.CurrentDomain.BaseDirectory}/save/father.lbs", false);
foreach(Child item in Children)
{
string sandwich = $"{item.ChildID};{item.Firstname};{item.Secondname};{item.Father.FatherID}";
swChild.WriteLine(sandwich);
}
swChild.Close();
foreach (Father item in Fathers)
{
string sandwich = $"{item.FatherID};{item.Firstname};{item.Secondname}";
swFather.WriteLine(sandwich);
}
swFather.Close();
MessageBox.Show("Complete");
}));
}
}
private RelayCommand _load;
public RelayCommand LoadButton
{
get
{
return _load ?? (_load = new RelayCommand(obj =>
{
StreamReader srChild = new StreamReader($"{AppDomain.CurrentDomain.BaseDirectory}/save/child.lbs", false);
StreamReader srFather = new StreamReader($"{AppDomain.CurrentDomain.BaseDirectory}/save/father.lbs", false);
string lineChild, lineFather;
while((lineFather = srFather.ReadLine()) != null)
{
string[] word = lineFather.Split(';');
Father f = new Father();
f.FatherID = int.Parse(word[0]);
f.Firstname = word[1];
f.Secondname = word[2];
Fathers.Insert(Fathers.Count, f);
}
while((lineChild = srChild.ReadLine()) != null)
{
string[] word = lineChild.Split(';');
Child c = new Child();
c.ChildID = int.Parse(word[0]);
c.Firstname = word[1];
c.Secondname = word[2];
//c.Father.FatherID = int.Parse(word[3]);
Children.Insert(Children.Count, c);
}
srChild.Close();
MessageBox.Show("Complete");
}));
}
}
public ContextView(){
Fathers = new ObservableCollection<Father>();
Children = new ObservableCollection<Child>();
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged([CallerMemberName] string prop = "")
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(prop));
}
}
}
There is a Project: https://github.com/RodKingroo/FatherChild
Who will help, thanks :)

Thanks, #BionicCode 4 ur help
Answer ContextWiew.cs:
using (StreamReader srChild = new StreamReader($"{AppDomain.CurrentDomain.BaseDirectory}/save/child.lbs")) {
lineChild = srChild.ReadLine();
while ((lineChild = srChild.ReadLine()) != null)
{
string[] word = lineChild.Split(';');
Child c = new Child();
c.ChildID = int.Parse(word[0]);
c.Firstname = word[1];
p.Secondname = word[2];
foreach (Father item in Father)
{
if (item.FatherID == int.Parse(word[5])) p.Father = item;
}
Children.Add(c);
SelectedChildren = c;
}
srChild.Close();
}

WPF MVVM properties binding not working properly

I have created a view model which has a single property for a student model, that I am then binding to a control in my XAML. But nothing is appearing when I execute the application.
I am setting data context in my app.xaml.cs as follows:
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
Registrationformusinemvvm.MainWindow window = new MainWindow();
VMUser VM = new VMUser();
window.DataContext = VM;
window.Show();
}
Why is the binding not working?
This is my view model:
public class VMUser:BaseClass
{
private student _currentStudent;
public student CurrentStudent
{
get { return _currentStudent; }
set {
_currentStudent = value;
OnPropertyChanged("CurrentStudent");
}
}
}
My Student model class:
public class student:BaseClass
{
private string name="sumit";
public string Name
{
get { return name; }
set { name = value; OnPropertyChanged("Name"); }
}
private int rollNum;
public int RollNum
{
get { return rollNum; }
set { rollNum = value;OnPropertyChanged("RollNum"); }
}
private int phNum;
public int PhNum
{
get { return phNum; }
set { phNum = value;OnPropertyChanged("PhNum"); }
}
private string sub;
public string Sub
{
get { return sub; }
set { sub = value;OnPropertyChanged("Sub"); }
}
}
My XAML:
<Window x:Class="Registrationformusinemvvm.MainWindow"
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:Registrationformusinemvvm"
xmlns:vm="clr-namespace:Registrationformusinemvvm.ViewModel"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<!--<Window.DataContext>
<vm:VMUser/>
</Window.DataContext>-->
<Window.Resources>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
<RowDefinition Height="50"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200"/>
<ColumnDefinition Width="200"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Text="Name" Grid.Column="0" Grid.Row="0" FontSize="14"
FontWeight="Bold" VerticalAlignment="Center"
HorizontalAlignment="Center"/>
<TextBlock Text="Roll Number" Grid.Column="0" Grid.Row="1" FontSize="14"
FontWeight="Bold" VerticalAlignment="Center"
HorizontalAlignment="Center"/>
<TextBlock Text="Subject" Grid.Column="0" Grid.Row="2" FontSize="14"
FontWeight="Bold" VerticalAlignment="Center"
HorizontalAlignment="Center"/>
<TextBlock Text="Phone Number" Grid.Column="0" Grid.Row="3"
FontSize="14" FontWeight="Bold" VerticalAlignment="Center"
HorizontalAlignment="Center"/>
<TextBox Name="tbName" Text="{Binding CurrentStudent.Name,Mode=TwoWay,
UpdateSourceTrigger=PropertyChanged}" Grid.Column="1" Grid.Row="0"
Width="120" Height="30" HorizontalAlignment="Center"
VerticalAlignment="Center"/>
<TextBox Name="tbRollnum" Text="{Binding CurrentStudent.RollNum}"
Grid.Column="1" Grid.Row="1" Width="120" Height="30"
HorizontalAlignment="Center" VerticalAlignment="Center"/>
<TextBox Name="tbSub" Text="{Binding CurrentStudent.Sub}"
Grid.Column="1" Grid.Row="2" Width="120" Height="30"
HorizontalAlignment="Center" VerticalAlignment="Center"/>
<TextBox Name="tbPh" Text="{Binding CurrentStudent.PhNum}"
Grid.Column="1" Grid.Row="3" Width="120" Height="30"
HorizontalAlignment="Center" VerticalAlignment="Center"/>
<Button Name="tbSubmit" Content="Submit" Grid.ColumnSpan="3"
Grid.Row="4" Height="30" Width="100" HorizontalAlignment="Center"/>
</Grid>
</Window>

My guess is that your binding isn't working because your _currentStudent is null by default. Initialize your _currentStudent if null.
public student CurrentStudent
{
get { return _currentStudent = (_currentStudent ?? new student()); }
set
{
_currentStudent = value; OnPropertyChanged("CurrentStudent");
}
}

You need to add OnPropertyChanged in your model class.
void OnPropertyChanged(string prop)
{
if (this.PropertyChanged != null)
this.PropertyChanged(this, new PropertyChangedEventArgs(prop));
}
public event PropertyChangedEventHandler PropertyChanged;

As per your above code you cant assigned the value to CurrentStudent Property so
can you please check do you have the value to CurrentStudent property.
Thank you for your question

Remove StartupUri="YourXamlFile.xaml" from App.Xaml

WPF C# datagrid combobox on new row won't update datasource (updated!)

This is an example exhibiting the behaviour I'm having trouble with. I have a datagrid which is bound to an observable collection of records in a viewmodel. In the datagrid I have a DataGridTemplateColumn holding a combobox which is populated from a list in the viewmodel. The datagrid also contains text columns. There are some textboxes at the bottom of the window to show the record contents.
<Window x:Class="Customer.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:Customer"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<local:SelectedRowConverter x:Key="selectedRowConverter"/>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="8*"/>
<RowDefinition Height="3*"/>
</Grid.RowDefinitions>
<DataGrid x:Name="dgCustomers" AutoGenerateColumns="False"
ItemsSource="{Binding customers}" SelectedItem="{Binding SelectedRow,
Converter={StaticResource selectedRowConverter}, Mode=TwoWay}"
CanUserAddRows="True" Grid.Row="0" SelectionChanged="dgCustomers_SelectionChanged">
<DataGrid.Columns>
<DataGridTemplateColumn Width="Auto" Header="Country">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox x:Name="cmbCountry" ItemsSource="{Binding DataContext.countries,
RelativeSource={RelativeSource AncestorType={x:Type Window}}}"
DisplayMemberPath="name" SelectedValuePath="name" Margin="5"
SelectedItem="{Binding DataContext.SelectedCountry,
RelativeSource={RelativeSource AncestorType={x:Type Window}}, Mode=TwoWay,
UpdateSourceTrigger=PropertyChanged}" SelectionChanged="cmbCountry_SelectionChanged" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTextColumn Header="Name" Binding="{Binding name}" Width="1*"/>
<DataGridTextColumn Header="Phone" Binding="{Binding phone}" Width="1*"/>
</DataGrid.Columns>
</DataGrid>
<Grid x:Name="grdDisplay" DataContext="{Binding ElementName=dgCustomers}" Grid.Row="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="1*"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="2" Content="Country:" VerticalAlignment="Center" HorizontalAlignment="Right"/>
<Label Grid.Column="4" Content="Code:" VerticalAlignment="Center" HorizontalAlignment="Right"/>
<BulletDecorator Grid.Column="0">
<BulletDecorator.Bullet>
<Label Content="Name:" VerticalAlignment="Center" HorizontalAlignment="Right"/>
</BulletDecorator.Bullet>
<TextBox x:Name="txtId" Text="{Binding ElementName=dgCustomers, Path=SelectedItem.name}" Margin="5,5,5,5"/>
</BulletDecorator>
<BulletDecorator Grid.Column="1">
<BulletDecorator.Bullet>
<Label Content="Code:" VerticalAlignment="Center" HorizontalAlignment="Right"/>
</BulletDecorator.Bullet>
<TextBox x:Name="txtCode" Text="{Binding ElementName=dgCustomers, Path=SelectedItem.countryCode}" Margin="5,5,5,5"/>
</BulletDecorator>
<BulletDecorator Grid.Column="2">
<BulletDecorator.Bullet>
<Label Content="Phone:" VerticalAlignment="Center" HorizontalAlignment="Right"/>
</BulletDecorator.Bullet>
<TextBox x:Name="txtPhone" Text="{Binding ElementName=dgCustomers, Path=SelectedItem.phone}" Margin="5,5,5,5"/>
</BulletDecorator>
</Grid>
</Grid>
</Window>
Initially there are no records so the datagrid is empty and shows just one line containing the combobox. If the user enters data into the text columns first then a record is added to the collection and the combobox value can be added to the record. However, if the user selects the combobox value first, then the value disappears when another column is selected. How do I get the combobox data added to the record if it is selected first?
Codebehind:
public partial class MainWindow : Window
{
public GridModel gridModel { get; set; }
public MainWindow()
{
InitializeComponent();
gridModel = new GridModel();
//dgCustomers.DataContext = gridModel;
this.DataContext = gridModel;
}
private void cmbCountry_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ComboBox c = sender as ComboBox;
Debug.Print("ComboBox selection changed, index is " + c.SelectedIndex + ", selected item is " + c.SelectedItem);
}
}
The Record class:
public class Record : ViewModelBase
{
private string _name;
public string name
{
get { return _name; }
set
{
_name = value;
OnPropertyChanged("name");
}
}
private string _phone;
public string phone
{
get { return _phone; }
set
{
_phone = value;
OnPropertyChanged("phone");
}
}
private int _countryCode;
public int countryCode
{
get { return _countryCode; }
set
{
_countryCode = value;
OnPropertyChanged("countryCode");
}
}
}
Country class:
public class Country : ViewModelBase
{
private string _name;
public string name
{
get { return _name; }
set
{
_name = value;
OnPropertyChanged("name");
}
}
private int _id;
public int id
{
get { return _id; }
set
{
_id = value;
OnPropertyChanged("id");
}
}
private int _code;
public int code
{
get { return _code; }
set
{
_code = value;
OnPropertyChanged("code");
}
}
public override string ToString()
{
return _name;
}
}
GridModel:
public class GridModel : ViewModelBase
{
public ObservableCollection<Record> customers { get; set; }
public List<Country> countries { get; set; }
public GridModel()
{
customers = new ObservableCollection<Record>();
countries = new List<Country> { new Country { id = 1, name = "England", code = 44 }, new Country { id = 2, name = "Germany", code = 49 },
new Country { id = 3, name = "US", code = 1}, new Country { id = 4, name = "Canada", code = 11 }};
}
private Country _selectedCountry;
public Country SelectedCountry
{
get
{
return _selectedCountry;
}
set
{
_selectedCountry = value;
_selectedRow.countryCode = _selectedCountry.code;
OnPropertyChanged("SelectedRow");
}
}
private Record _selectedRow;
public Record SelectedRow
{
get
{
return _selectedRow;
}
set
{
_selectedRow = value;
Debug.Print("Datagrid selection changed");
OnPropertyChanged("SelectedRow");
}
}
}
Converters:
class Converters
{
}
public class SelectedRowConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return value;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
if (value is Record)
return value;
return new Customer.Record();
}
}
ViewModelBase:
public class ViewModelBase : INotifyPropertyChanged
{
public ViewModelBase()
{
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string name)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(name));
}
}
}

The behaviour you are seeing is as expected. The reason behind it is that the ComboBox ItemsSource as well as SelectedItem both are bound to Properties of the Window's DataContext while the other columns are bound to your DataGrid's ItemsSource. Hence when you modify the columns other than the dropdown the data is added to the observable collection.
What you can do is after a value is selected from the drop down you need to add a record yourself (possibly by calling a function from your SelectedCountry property)
EDIT
Based on your code I made a working model making as little changes as possible to your existing code. I could not use the converter as I did not have the details of the class Customer
Xaml
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="8*"/>
<RowDefinition Height="3*"/>
</Grid.RowDefinitions>
<StackPanel Grid.Row="0">
<Button HorizontalAlignment="Right" Content="Add User" Margin="0,2,2,2" Command="{Binding AddUserCommand}"/>
<DataGrid x:Name="dgCustomers"
AutoGenerateColumns="False"
ItemsSource="{Binding customers}"
SelectedItem="{Binding SelectedRow}"
SelectionUnit="FullRow"
CanUserAddRows="False">
<DataGrid.Columns>
<DataGridTemplateColumn Width="Auto" Header="Country">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox Focusable="False"
ItemsSource="{Binding DataContext.countries, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}}"
DisplayMemberPath="name"
SelectedValuePath="code"
SelectedValue="{Binding countryCode, UpdateSourceTrigger=PropertyChanged}"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTextColumn Header="Name" Binding="{Binding name, UpdateSourceTrigger=PropertyChanged}" Width="1*"/>
<DataGridTextColumn Header="Phone" Binding="{Binding phone, UpdateSourceTrigger=PropertyChanged}" Width="1*"/>
</DataGrid.Columns>
</DataGrid>
</StackPanel>
<Grid x:Name="grdDisplay" DataContext="{Binding ElementName=dgCustomers}" Grid.Row="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="1*"/>
</Grid.ColumnDefinitions>
<Label Grid.Column="2" Content="Country:" VerticalAlignment="Center" HorizontalAlignment="Right"/>
<Label Grid.Column="4" Content="Code:" VerticalAlignment="Center" HorizontalAlignment="Right"/>
<BulletDecorator Grid.Column="0">
<BulletDecorator.Bullet>
<Label Content="Name:" VerticalAlignment="Center" HorizontalAlignment="Right"/>
</BulletDecorator.Bullet>
<TextBox x:Name="txtId" Text="{Binding ElementName=dgCustomers, Path=SelectedItem.name}" Margin="5,5,5,5"/>
</BulletDecorator>
<BulletDecorator Grid.Column="1">
<BulletDecorator.Bullet>
<Label Content="Code:" VerticalAlignment="Center" HorizontalAlignment="Right"/>
</BulletDecorator.Bullet>
<TextBox x:Name="txtCode" Text="{Binding ElementName=dgCustomers, Path=SelectedItem.countryCode}" Margin="5,5,5,5"/>
</BulletDecorator>
<BulletDecorator Grid.Column="2">
<BulletDecorator.Bullet>
<Label Content="Phone:" VerticalAlignment="Center" HorizontalAlignment="Right"/>
</BulletDecorator.Bullet>
<TextBox x:Name="txtPhone" Text="{Binding ElementName=dgCustomers, Path=SelectedItem.phone}" Margin="5,5,5,5"/>
</BulletDecorator>
</Grid>
</Grid>
Your GridModel class
public class GridModel : ViewModelBase
{
public ObservableCollection<Record> customers { get; set; }
public ObservableCollection<Country> countries
{
get;
private set;
}
public GridModel()
{
customers = new ObservableCollection<Record> { };
AddUserCommand = new RelayCommand(AddNewUser);
countries = new ObservableCollection<Country>
{
new Country { id = 1, name = "England", code = 44 },
new Country { id = 2, name = "Germany", code = 49 },
new Country { id = 3, name = "US", code = 1},
new Country { id = 4, name = "Canada", code = 11 }
};
}
private void AddNewUser()
{
customers.Add(new Record());
}
public ICommand AddUserCommand { get; set; }
private Record _selectedRow;
public Record SelectedRow
{
get
{
return _selectedRow;
}
set
{
_selectedRow = value;
Debug.Print("Datagrid selection changed");
OnPropertyChanged("SelectedRow");
}
}
}
I have used MVVMLight toolkit which contains RelayCommand. You can also define your own ICommand implementation and use it instead of the toolkit
EDIT 2
Fixed the bug introduced by me which would prevent the combobox from displaying the Country if the data comes from the data base. The improved code does not require any converter either

Having problems binding my datagrid to data from my database

i've a problem to use datagrid in wpf mvvm project
Here is my xaml :
<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors"
x:Class="noteManager.MainWindow"
xmlns:vm="clr-namespace:noteManager.ViewModel"
DataContext="{StaticResource noteManagerViewModel}"
Title="NoteManager" Height="490" Width="525">
<Grid Margin="0,0,0,-132.5">
<Grid.RowDefinitions>
<RowDefinition Height="10"></RowDefinition>
<RowDefinition Height="50"></RowDefinition>
<RowDefinition Height="200"></RowDefinition>
<RowDefinition Height="40"></RowDefinition>
<RowDefinition Height="110"></RowDefinition>
<RowDefinition Height="111"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="10"></ColumnDefinition>
<ColumnDefinition Width="80"></ColumnDefinition>
<ColumnDefinition Width="100"></ColumnDefinition>
<ColumnDefinition Width="80"></ColumnDefinition>
<ColumnDefinition Width="100"></ColumnDefinition>
<ColumnDefinition Width="50"></ColumnDefinition>
<ColumnDefinition Width="50"></ColumnDefinition>
</Grid.ColumnDefinitions>
<TextBlock Text="Login :" FontSize="16" Grid.Column="2" Margin="51,9,50,0" Grid.RowSpan="2" Height="23" VerticalAlignment="Top" Grid.ColumnSpan="2"/>
<TextBox Text="{Binding Login}" Grid.Row="1" Grid.Column="3" Margin="14,0,86,29" Grid.ColumnSpan="2"/>
<Button Background="LightGreen" Foreground="Green" Command="{Binding testConnexion}" x:Name="testConnexion" Content="Connexion" Grid.Row="1" Grid.Column="2" Margin="51,29,86,0" Grid.ColumnSpan="3"/>
<Button Command="{Binding addUser}" Content="+" Grid.Row="1" Grid.Column="4" Margin="34,1,20,0" RenderTransformOrigin="0.742,0.468"/>
<DataGrid Name="dataGrid1" Grid.Row="2" Margin="8,7,-22,7" AutoGenerateColumns="False"
ItemsSource="{Binding _DataGridNotes}" SelectedItem="{Binding Path=MySelectedNote}" HorizontalAlignment="Center"
Width="480" Grid.ColumnSpan="6" Grid.Column="1">
<DataGrid.Columns>
<DataGridTextColumn Width="100" Binding="{Binding Path=NoteTitle}" Header="Titre" />
<DataGridTextColumn Width="200" Binding="{Binding Path=NoteContent}" Header="Note" />
<DataGridTextColumn Width="100" Binding="{Binding Path=NoteCreatedAt}" Header="Date de création" />
<DataGridTextColumn Width="100" Binding="{Binding Path=NoteUpdatedAt}" Header="Dat MAJ" />
</DataGrid.Columns>
</DataGrid>
<TextBlock Text="Titre" FontSize="16" Grid.Row="3" Grid.Column="1" Margin="27,8,7,1"/>
<TextBox Text="{Binding Path=titre, Mode=TwoWay}" Grid.Row="3" Grid.Column="2" Margin="17,10,23,10" Grid.ColumnSpan="5"/>
<TextBlock Text="Note" FontSize="16" Grid.Row="4" Grid.Column="1" Margin="27,4,7,0"/>
<TextBox Text="{Binding Path=description, Mode=TwoWay}" Grid.Row="4" Grid.Column="2" Margin="17,10,23,8" Grid.ColumnSpan="5"/>
<Button Command="{Binding Path=DeleteNote}" Background="LightPink" Foreground="red" Content="Supprimer" Grid.Row="5" Grid.Column="1" Margin="55,7,26,81" Grid.ColumnSpan="2"/>
<Button Command="{Binding Path=UpdateANote}" Content="Mettre à jour" Grid.Row="5" Grid.Column="3" Margin="14,7,67,81" Grid.ColumnSpan="2" RenderTransformOrigin="0.5,0.5"/>
<Button Command="{Binding Path=AddNote}" Content="Ajouter" Grid.Row="5" Grid.Column="4" Margin="78,7,10,81" Grid.ColumnSpan="3"/>
</Grid>
</Window>
Here is my viewModel :
namespace noteManager.ViewModel
{
public class noteManagerViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
void Notify(string property)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(property));
}
}
string login;
int currentUser;
public string Login
{
get
{
return login;
}
set
{
login = value; Notify("Login");
}
}
private bool _canExecute;
public noteManagerViewModel()
{
_canExecute = true;
}
private ICommand _testConnexion;
public ICommand testConnexion
{
get
{
return _testConnexion ?? (_testConnexion = new CommandHandler(() => Connexion(), _canExecute));
}
}
private ICommand _addUser;
public ICommand addUser
{
get
{
return _addUser ?? (_addUser = new CommandHandler(() => AjoutUser(), _canExecute));
}
}
private ObservableCollection<DataGridNotes> _DataGridNotes = new ObservableCollection<DataGridNotes>();
public ObservableCollection<DataGridNotes> dataGridNotes
{
// No need for a public setter
get { return _DataGridNotes; }
}
}
the other class that i use :
public class User
{
/*public User()
{
this.Note = new HashSet<Note>();
}*/
public int Id { get; set; }
public string Login { get; set; }
//public virtual ICollection<Note> Note { get; set; }
}
public class Note : INotifyPropertyChanged
{
public int Id { get; set; }
public string NoteText { get; set; }
public string ContentText { get; set; }
public DateTime CreatedAt { get; set; }
public DateTime? UpdatedAt { get; set; }
public int UserId { get; set; }
//public virtual User User { get; set; }
public event PropertyChangedEventHandler PropertyChanged;
public void Notify(string property)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(property));
}
}
}
public class DataGridNotes
{
private string _noteTitle;
private string _noteContent;
private string _noteCreatedAt;
private string _noteUpdatedAt;
public string NoteTitle { get { return _noteTitle; } set { _noteTitle = value; } }
public string NoteContent { get { return _noteContent; } set { _noteContent = value; } }
public string NoteCreatedAt { get { return _noteCreatedAt; } set { _noteCreatedAt = value; } }
public string NoteUpdatedAt { get { return _noteUpdatedAt; } set { _noteUpdatedAt = value; } }
}
sorry for the ugly code, new to c# for a project.
i want to use the datagrid in my viewmodel but don't find a way to make it work (would like to write data from mysql database in the datagrid
Have you an idea to make it work ?
thx in advance

Ok, It's tough to spot what you are doing wrong without seeing the ViewModel, however you may want to check the following:
1) The DataContext is correct.
2) The property _DataGridNotes exists. Check the program output to make sure that there are no warnings informing you that bindings are broken.
The property you are looking to have should look something like this:
List<Note> _DataGridNotes
{
get
{
// get notes from SQL request
// construct list of Note and return list
}
}
You should also make sure that the Note class contains the properties required (NoteTitle, NoteContent, NoteCreatedAt, NoteUpdatedAt).
It might also be worth passing back some dummy notes to debug if the problem lies in the request to the SQL database.

The problem is that you are trying to bind to a private Observable collection _DataGridNotes where you should be binding to the property dataGridNotes:
ItemsSource="{Binding dataGridNotes}"

Windows Phone - Binding View to View Model

So, I am on my way learning MVVM Pattern for Windows Phone, and stuck how to bind the View to my ViewModel. App that I build now is getting current and next 5 days weather and display it to one of my panorama item on MainPage.xaml using UserControl.
I cannot just simply set the Forecasts.ItemsSource = forecast; in my WeatherViewModel, it says that Forecasts (Listbox element name in WeatherView) not exist in the current context.
Can anybody teach me how to bind it? and anybody have a good source/example sample to mvvm pattern in windows-phone? Thanks before.
EDIT:
WeatherModel.cs
namespace JendelaBogor.Models
{
public class WeatherModel
{
public string Date { get; set; }
public string ObservationTime { get; set; }
public string WeatherIconURL { get; set; }
public string Temperature { get; set; }
public string TempMaxC { get; set; }
public string TempMinC { get; set; }
public string Humidity { get; set; }
public string WindSpeedKmph { get; set; }
}
}
WeatherViewModel.cs
namespace JendelaBogor.ViewModels
{
public class WeatherViewModel : ViewModelBase
{
private string weatherURL = "http://free.worldweatheronline.com/feed/weather.ashx?q=";
private const string City = "Bogor,Indonesia";
private const string APIKey = "APIKEY";
private IList<WeatherModel> _forecasts;
public IList<WeatherModel> Forecasts
{
get
{
if (_forecasts == null)
{
_forecasts = new List<WeatherModel>();
}
return _forecasts;
}
private set
{
_forecasts = value;
if (value != _forecasts)
{
_forecasts = value;
this.NotifyPropertyChanged("Forecasts");
}
}
}
public WeatherViewModel()
{
WebClient downloader = new WebClient();
Uri uri = new Uri(weatherURL + City + "&num_of_days=5&extra=localObsTime&format=xml&key=" + APIKey, UriKind.Absolute);
downloader.DownloadStringCompleted += new DownloadStringCompletedEventHandler(ForecastDownloaded);
downloader.DownloadStringAsync(uri);
}
private void ForecastDownloaded(object sender, DownloadStringCompletedEventArgs e)
{
if (e.Result == null || e.Error != null)
{
MessageBox.Show("Cannot load Weather Forecast!");
}
else
{
XDocument document = XDocument.Parse(e.Result);
var current = from query in document.Descendants("current_condition")
select new WeatherModel
{
ObservationTime = DateTime.Parse((string)query.Element("localObsDateTime")).ToString("HH:mm tt"),
Temperature = (string)query.Element("temp_C"),
WeatherIconURL = (string)query.Element("weatherIconUrl"),
Humidity = (string)query.Element("humidity"),
WindSpeedKmph = (string)query.Element("windspeedKmph")
};
this.Forecasts = (from query in document.Descendants("weather")
select new WeatherModel
{
Date = DateTime.Parse((string)query.Element("date")).ToString("dddd"),
TempMaxC = (string)query.Element("tempMaxC"),
TempMinC = (string)query.Element("tempMinC"),
WeatherIconURL = (string)query.Element("weatherIconUrl")
}).ToList();
}
}
}
}
WeatherView.xaml
<UserControl x:Class="JendelaBogor.Views.WeatherView"
xmlns:vm="clr-namespace:JendelaBogor.ViewModels">
<UserControl.DataContext>
<vm:WeatherViewModel />
</UserControl.DataContext>
<Grid Margin="0,-10,0,0">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid x:Name="Current" Grid.Row="0" Height="150" VerticalAlignment="Top">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="150"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Image Grid.Column="0" delay:LowProfileImageLoader.UriSource="{Binding WeatherIconURL}" Width="120" Height="120" VerticalAlignment="Top"/>
<StackPanel Grid.Column="1" Height="200" VerticalAlignment="Top">
<TextBlock Text="{Binding Temperature}" FontSize="22"/>
<TextBlock Text="{Binding ObservationTime}" FontSize="22"/>
<TextBlock Text="{Binding Humidity}" FontSize="22"/>
<TextBlock Text="{Binding Windspeed}" FontSize="22"/>
</StackPanel>
</Grid>
<Grid Grid.Row="1" Height="300" VerticalAlignment="Bottom" Margin="10,0,0,0">
<StackPanel VerticalAlignment="Top">
<StackPanel Height="40" Orientation="Horizontal" Margin="0,0,0,0">
<TextBlock Text="Date" FontSize="22" Width="170"/>
<TextBlock Text="FC" FontSize="22" Width="60"/>
<TextBlock Text="Max" TextAlignment="Right" FontSize="22" Width="90"/>
<TextBlock Text="Min" TextAlignment="Right" FontSize="22" Width="90"/>
</StackPanel>
<StackPanel Orientation="Horizontal">
<ListBox ItemsSource="{Binding Forecasts}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Height="40" Orientation="Horizontal" Margin="0,10,0,0">
<TextBlock Text="{Binding Date}" FontSize="22" TextAlignment="Left" Width="170" />
<Image delay:LowProfileImageLoader.UriSource="{Binding WeatherIconURL}" Width="40" Height="40" />
<TextBlock Text="{Binding TempMaxC, StringFormat='\{0\} °C'}" TextAlignment="Right" FontSize="22" Width="90" />
<TextBlock Text="{Binding TempMinC, StringFormat='\{0\} °C'}" TextAlignment="Right" FontSize="22" Width="90" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
</StackPanel>
</Grid>
</Grid>
</UserControl>
MainPage.xaml
<controls:PanoramaItem x:Name="Weather" Header="weather">
<views:WeatherView />
</controls:PanoramaItem>

You need to tell the view what viewmodel you are using. By adding
<UserControl
xmlns:vm="clr-namespace:JendelaBogor.ViewModels">
<UserControl.DataContext>
<vm:WeatherViewModel />
</UserControl.DataContext>
</UserControl>
all {Binding}'s are mapped to the class WeatherViewModel. By using the ItemsSource property on the listbox as Reed suggests you can then bind all items from a list that you expose through a property.
If the list is ever changed while running the application, consider using an ObservableCollection and clearing it and adding all new items when new data is received. If you do, your GUI will simply update with it.

The ViewModel doesn't know about the view.
You need to make a Forecasts property on the ViewModel, and bind the ItemsSource to it from your View. In your view, change the ListBox to:
<!-- No need for a name - just add the binding -->
<ListBox ItemsSource="{Binding Forecasts}">
Then, in your ViewModel, add:
// Add a backing field
private IList<WeatherModel> forecasts;
// Add a property implementing INPC
public IList<WeatherModel> Forecasts
{
get { return forecasts; }
private set
{
forecasts = value;
this.RaisePropertyChanged("Forecasts");
}
}
You can then set this in your method:
this.Forecasts = (from query in document.Descendants("weather")
select new WeatherModel
{
Date = DateTime.Parse((string)query.Element("date")).ToString("dddd"),
TempMaxC = (string)query.Element("tempMaxC"),
TempMinC = (string)query.Element("tempMinC"),
WeatherIconURL = (string)query.Element("weatherIconUrl")
})
.ToList(); // Turn this into a List<T>