Updating ComboBox in XAML without Somegrid.Items.Refresh()

Updating ComboBox in XAML without Somegrid.Items.Refresh() - c#

I'm new in WPF+C# and starting to get a grip on it.
I want to update ComboBox inside DataGrid when program is running.
Unfortunately, ComboBox never show any selected item if I'm using Somegrid.Item.Refresh() to update DataGrid.
Here is the XAML
<Window x:Class="WpfApplication1.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 Name="Somegrid" HorizontalAlignment="Left" AutoGenerateColumns="False" CanUserAddRows="False" CanUserDeleteRows="False">
<DataGrid.Columns>
<DataGridTemplateColumn>
<DataGridTemplateColumn.Header>
<TextBlock Text="SomebodY" />
</DataGridTemplateColumn.Header>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding Somebody}" SelectionChanged="ComboBox_SelectionChanged_Somebody" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTemplateColumn>
<DataGridTemplateColumn.Header>
<TextBlock Text="SomethinG" />
</DataGridTemplateColumn.Header>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding Something}" SelectionChanged="ComboBox_SelectionChanged_Something" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTemplateColumn>
<DataGridTemplateColumn.Header>
<TextBlock Text="SomewherE" />
</DataGridTemplateColumn.Header>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding Somewhere}" SelectionChanged="ComboBox_SelectionChanged_Somewhere" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
</Grid>
</Window>
Behind code
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Windows;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
someclassFoo.Somebody = new List<string>() { "Alan", "Benjamin" };
observableSomeclassFoo.Add(someclassFoo);
Somegrid.ItemsSource = observableSomeclassFoo;
}
public SomeclassFoo someclassFoo = new SomeclassFoo();
private ObservableCollection<SomeclassFoo> _observableSomeclassFoo = new ObservableCollection<SomeclassFoo>();
public ObservableCollection<SomeclassFoo> observableSomeclassFoo { get { return _observableSomeclassFoo; } }
private void ComboBox_SelectionChanged_Somebody(object sender, RoutedEventArgs e)
{
System.Windows.Controls.ComboBox cb1 = (System.Windows.Controls.ComboBox)sender;
if (cb1.SelectedItem.ToString() == "Alan")
{
someclassFoo.Something = new List<string>() { "Apple" };
}
else if (cb1.SelectedItem.ToString() == "Benjamin")
{
someclassFoo.Something = new List<string>() { "Banana" };
}
//Somegrid.Items.Refresh();
}
private void ComboBox_SelectionChanged_Something(object sender, RoutedEventArgs e)
{
System.Windows.Controls.ComboBox cb2 = (System.Windows.Controls.ComboBox)sender;
if (cb2.SelectedItem.ToString() == "Apple")
{
someclassFoo.Somewhere = new List<string>() { "Antartica" };
}
else if (cb2.SelectedItem.ToString() == "Banana")
{
someclassFoo.Somewhere = new List<string>() { "Bedrock" };
}
//Somegrid.Items.Refresh();
}
private void ComboBox_SelectionChanged_Somewhere(object sender, RoutedEventArgs e)
{
System.Windows.Controls.ComboBox cb3 = (System.Windows.Controls.ComboBox)sender;
MessageBox.Show(cb3.SelectedItem.ToString().ToUpper() + " selected");
}
}
}
Another class
using System.Collections.Generic;
namespace WpfApplication1
{
public class SomeclassFoo
{
public IList<string> Somebody { get; set; }
public IList<string> Something { get; set; }
public IList<string> Somewhere { get; set; }
}
}
How I can update the ComboBox SomethinG and ComboBox SomewherE without using Somegrid.Item.Refresh() ?

The SomeclassFoo type should implement the INotifyPropertyChanged interface and raise change notifications:
public class SomeclassFoo : INotifyPropertyChanged
{
private IList<string> _somebody;
public IList<string> Somebody
{
get { return _somebody; }
set { _somebody = value; NotifyPropertyChanged(); }
}
private IList<string> _something;
public IList<string> Something
{
get { return _something; }
set { _something = value; NotifyPropertyChanged(); }
}
private IList<string> _someWhere;
public IList<string> Somewhere
{
get { return _someWhere; }
set { _someWhere = value; NotifyPropertyChanged(); }
}
public event PropertyChangedEventHandler PropertyChanged;
private void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
How to: Implement Property Change Notification: https://msdn.microsoft.com/en-us/library/ms743695(v=vs.110).aspx

Instead of refreshing the grid, remove the current source and set a new source:
yourGrid.ItemsSource = null;
yourGrid.ItemsSource = yourDataSource;

Related

Cannot get selected ComboBox items in MainWindow.xaml.cs

I'd like to access ComboBox items (which are defined in another class) in MainWindow.xaml.cs, but I can't.
I'm new to C# and WPF. The purpose of this code is to get a selected ComboBox item as a search key. I have copied from many example codes on the Internet and now I'm completely lost. I don't even know which part is wrong. So, let me show the entire codes (sorry):
MainWindow.xaml:
<Window x:Class="XY.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:XY"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="454.4">
<Grid>
<DataGrid ItemsSource="{Binding channels}"
SelectedItem="{Binding SelectedRow, Mode=TwoWay}"
Margin="0,0,0,-0.2">
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding name}"
Header="Channel" Width="Auto"/>
<DataGridTemplateColumn Width="100" Header="Point Setting">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox x:Name="piontsComboBox"
ItemsSource="{Binding DataContext.points,
RelativeSource={RelativeSource AncestorType={x:Type Window}}}"
SelectionChanged="PrintText"
DisplayMemberPath="name"
SelectedValuePath="name"
Margin="5"
SelectedItem="{Binding DataContext.SelectedPoint,
RelativeSource={RelativeSource AncestorType={x:Type Window}},
Mode=TwoWay}"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
<TextBox x:Name="tb" Width="140" Height="30" Margin="10,250,200,30"></TextBox>
<Button x:Name="Browse_Button" Content="Browse" Margin="169,255,129.6,0"
Width="75" Click="Browse_Button_Click" Height="30" VerticalAlignment="Top"/>
</Grid>
MainWindow.xaml.cs:
using System;
using System.Windows;
using System.Windows.Controls;
namespace XY
{
public partial class MainWindow : Window
{
public GridModel gridModel { get; set; }
public MainWindow()
{
InitializeComponent();
gridModel = new GridModel();
this.DataContext = gridModel;
}
private void Browse_Button_Click(object sender, RoutedEventArgs e)
{
WakeupClass clsWakeup = new WakeupClass();
clsWakeup.BrowseFile += new EventHandler(gridModel.ExcelFileOpen);
clsWakeup.Start();
}
void PrintText(object sender, SelectionChangedEventArgs args)
{
//var item = pointsComboBox SelectedItem as Point;
//if(item != null)
//{
// tb.Text = "You selected " + item.name + ".";
//}
MessageBox.Show("I'd like to show the item.name in the TextBox.");
}
}
public class WakeupClass
{
public event EventHandler BrowseFile;
public void Start()
{
BrowseFile(this, EventArgs.Empty);
}
}
}
Point.cs:
namespace XY
{
public class Point : ViewModelBase
{
private string _name;
public string name
{
get { return _name; }
set
{
_name = value;
OnPropertyChanged("name");
}
}
private int _code;
public int code
{
get { return _code; }
set
{
_code = value;
OnPropertyChanged("code");
}
}
}
}
Record.cs:
namespace XY
{
public class Record : ViewModelBase
{
private string _name;
public string name
{
get { return _name; }
set
{
_name = value;
OnPropertyChanged("name");
}
}
private int _PointCode;
public int PointCode
{
get { return _PointCode; }
set
{
_PointCode = value;
OnPropertyChanged("PointCode");
}
}
private Record _selectedRow;
public Record selectedRow
{
get { return _selectedRow; }
set
{
_selectedRow = value;
OnPropertyChanged("SelectedRow");
}
}
private Point _selectedPoint;
public Point SelectedPoint
{
get { return _selectedPoint; }
set
{
_selectedPoint = value;
_selectedRow.PointCode = _selectedPoint.code;
OnPropertyChanged("SelectedRow");
}
}
}
}
ViewModelBase.cs:
using System.ComponentModel;
namespace XY
{
public class ViewModelBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string name)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(name));
}
}
}
}
GridModel.cs:
using System.Collections.ObjectModel;
using System.Windows;
namespace XY
{
public class GridModel : ViewModelBase
{
public ObservableCollection<Record> channels { get; set; }
public ObservableCollection<Point> points { get; set; }
public GridModel()
{
channels = new ObservableCollection<Record>() {
new Record {name = "High"},
new Record {name = "Middle"},
new Record {name = "Low"}
};
}
internal void ExcelFileOpen(object sender, System.EventArgs e)
{
points = new ObservableCollection<Point> { new Point { } };
points.Add(new Point { name = "point1", code = 1 });
points.Add(new Point { name = "point2", code = 2 });
points.Add(new Point { name = "point3", code = 3 });
MessageBox.Show("Assume that Excel data are loaded here.");
}
}
}
The procedure goes like:
Click on the "Browse" button to load the data.
Click on the 1st column "Channel" to sort the list (This is a bug, but if you don't, the "Point Setting" items won't show up).
Click on the "Point Setting" ComboBox to select the items (point1, point2, ..., etc.).
This code is supposed to show the selected item name in the TextBox.
If everything is in MainWindow.xaml.cs, the ComboBox items could be accessed. Since I split the codes into different classes, it has not been working. Please help me. Any suggestion would be helpful.

Your binding does work. You can make use of the sender object to achieve what you wanted.
void PrintText(object sender, SelectionChangedEventArgs args)
{
var comboBox = sender as ComboBox;
var selectedPoint = comboBox.SelectedItem as Point;
tb.Text = selectedPoint.name;
}

The problem is that the DataGridColumn is not part of the WPF logical tree and so your relative source binding will not work. The only way to get your binding to work is a type of kluge (very common with WPF in my experience). Create a dummy element that is in the logical tree and then reference that.
So
<FrameworkElement x:Name="dummyElement" Visibility="Collapsed"/>
<DataGrid ItemsSource="{Binding channels}"
SelectedItem="{Binding SelectedRow, Mode=TwoWay}"
Margin="0,0,0,-0.2">
Then your binding will look like this
<ComboBox x:Name="piontsComboBox"
ItemsSource="{Binding DataContext.points,
Source={x:Reference dummyElement}}"
SelectionChanged="PrintText"
DisplayMemberPath="name"
SelectedValuePath="name"
Margin="5"
SelectedItem="{Binding DataContext.SelectedPoint,
Source={x:Reference dummyElement},
Mode=TwoWay}"/>

Bind ObservableCollection to DataGrid with auto refresh

I'am trying to bind a ObservableCollection list to a datagrid.
The Values in the list change every 100ms.
I want that the grid automatically refreshs if a value changed.
Here is a little demo project to make it work. But without the refresh UI button, nothing works right.
public partial class MainWindow : Window
{
public ObservableCollection<DemoItem> ItemList = new ObservableCollection<DemoItem>();
public MainWindow()
{
InitializeComponent();
DemoItem di1 = new DemoItem();
di1.Name = "Spieler 1";
di1.Zufallszahl = 0;
di1.Alter = 21;
DemoItem di2 = new DemoItem();
di2.Name = "Spieler 2";
di2.Zufallszahl = 0;
di2.Alter = 15;
ItemList.Add(di1);
ItemList.Add(di2);
DispatcherTimer dt = new DispatcherTimer();
dt.Interval = new TimeSpan(0, 0, 0, 0, 100);
dt.Tick += Dt_Tick;
dt.Start();
}
public ObservableCollection<DemoItem> ObservableDemoItem
{
get
{
return this.ItemList;
}
}
private void Dt_Tick(object sender, EventArgs e)
{
Random rnd = new Random();
ItemList[0].Zufallszahl = rnd.Next(0, 1000);
ItemList[1].Zufallszahl = rnd.Next(0, 1000);
}
private void button1_Click(object sender, RoutedEventArgs e)
{
dataGrid.Items.Refresh();
}
}
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:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WpfApplication1"
mc:Ignorable="d"
Title="MainWindow" Height="359.428" Width="539.141">
<Grid>
<DataGrid x:Name="dataGrid" HorizontalAlignment="Left"
Margin="10,10,0,0" SelectionMode="Extended" VerticalAlignment="Top"
Height="199" Width="497" CanUserAddRows="False"
CanUserDeleteRows="False" AutoGenerateColumns="False"
DataContext="{Binding RelativeSource={RelativeSource AncestorType=Window}}"
ItemsSource="{Binding ObservableDemoItem}" >
<DataGrid.Columns>
<DataGridTextColumn Header="Name" Binding="{Binding Name}" />
<DataGridTextColumn Header="Alter" Binding="{Binding Alter}" />
<DataGridTextColumn Header="Aktiv" Binding="{Binding Zufallszahl}" />
</DataGrid.Columns>
</DataGrid>
<Button x:Name="button1" Content="Update UI" HorizontalAlignment="Left"
Margin="55,245,0,0" VerticalAlignment="Top"
Width="425" Height="61" Click="button1_Click"/>
</Grid>
</Window>
What do I need to change, to make it work?

ObservableCollection notifies the UI about changes (raises a CollectionChanged event) only if an element has been added or removed, not if an existing element has been changed.
To track changes in collection's elements, like Nitro.de and Ed Plunkett suggested, the element's class should implement INotifyPropertyChanged interface, like this:
using System.ComponentModel;
public class DemoItem : INotifyPropertyChanged
{
private int _age;
private int _score;
private string _name;
public int Age
{
get { return _age; }
set { if (_age != value) { _age = value; OnPropertyChanged("Age"); } }
}
public int Score
{
get { return _score; }
set { if (_score != value) { _score = value; OnPropertyChanged("Score"); } }
}
public string Name
{
get { return _name; }
set { if (_name != value) { _name = value; OnPropertyChanged("Name"); } }
}
public event PropertyChangedEventHandler PropertyChanged;
public void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}

Assuming your collection changes dramatically every 100 ms, I'd try sending Reset notification from the collection so DataGrid would know that the data needs to be refreshed.
You need to create an ObservableCollection derivative containing method similar to this one
public void NotifyOnReset()
{
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
and invoke it whenever you need.
P.S. Make sure you invoke this method on the UI thread, or employ another syncrhonization approach.

checkbox checked event trigger multiple time wpf mvvm

I got checkbox column in DataGrid that populating realtime download percentage in particular row, filtered by caseRefNo. i need to add checkbox changed event to perform some action. i used InvokeCommandAction to add the action to checkbox.
I realize that when i click the checkbox for the first time, It is ok and trigger only one time. but there are two times triggered when i click second time on the same checkbox.For third time clicking the same checkbox, it triggered four time. quite scary and difficult to figure it out.
here is my viewmodel code
public class DataGridDownloadViewModel:BindableBase
{
public ObservableCollection<tblTransaction> TransList { get; private set; }
public DispatcherTimer dispatchTimer = new DispatcherTimer();
public CollectionView TransView { get; private set; }
public DelegateCommand<object> CheckCommand { get; set; }
private String _UpdatePer;
public String UpdatePercentage
{
get { return _UpdatePer; }
set { SetProperty(ref _UpdatePer, value); }
}
private string _caseId;
public string CaseID
{
get { return _caseId; }
set { SetProperty(ref _caseId, value); }
}
private string _isChecked;
public string isChecked
{
get { return _isChecked; }
set { SetProperty(ref _isChecked, value); }
}
private bool CanExecute(object args)
{
return true;
}
private void CheckBoxChecker(object args)
{
//Should Work Here
// Totally not coming to this function
CheckBox chk = (CheckBox)args;
string thichintae = chk.Name.ToString();
Console.WriteLine(thichintae);
}
public DataGridDownloadViewModel(List<tblTransaction> model)
{
CheckCommand = new DelegateCommand<object>(CheckBoxChecker, CanExecute);
dispatchTimer.Interval = TimeSpan.FromMilliseconds(3000);
dispatchTimer.Tick += dispatchTimer_Tick;
BackGroundThread bgT = Application.Current.Resources["BackGroundThread"] as BackGroundThread;
bgT.GetPercentChanged += (ss, ee) =>
{
UpdatePercentage = bgT.local_percentage.ToString();
};
bgT.GetCaseID += (ss, ee) =>
{
CaseID = bgT.local_caseRef;
};
TransList =new ObservableCollection<tblTransaction>(model);
TransView = GetTransCollectionView(TransList);
TransView.Filter = OnFilterTrans;
var tokenSource = new CancellationTokenSource();
var token = tokenSource.Token;
var cancellationTokenSource = new CancellationTokenSource();
dispatchTimer.Start();
}
private void dispatchTimer_Tick(object sender, EventArgs e)
{
UpdateDataGrid();
}
public void UpdateDataGrid()
{
foreach (tblTransaction tran in TransList)
{
if (tran.caseRefNo == CaseID)
{
tran.incValue = int.Parse(UpdatePercentage);
}
else
{
tran.incValue = tran.incValue;
}
}
TransView.Refresh();
}
bool OnFilterTrans(object item)
{
var trans = (tblTransaction)item;
return true;
}
public CollectionView GetTransCollectionView(ObservableCollection<tblTransaction> tranList)
{
return (CollectionView)CollectionViewSource.GetDefaultView(tranList);
}
}
this is XAML for above view model.
<Window x:Class="EmployeeManager.View.DataGridDownload"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"
Title="DataGridDownload" Height="600" Width="790">
<Grid>
<DataGrid HorizontalAlignment="Left" ItemsSource="{Binding TransView}" AutoGenerateColumns="False" Margin="10,62,0,0" VerticalAlignment="Top" Height="497" Width="762">
<DataGrid.Columns>
<DataGridTextColumn Header="caseRefNo" Binding="{Binding caseRefNo}" />
<DataGridTextColumn Header="subjMatr" Binding="{Binding subjMatr}" />
<DataGridTextColumn Header="Download %" Binding="{Binding incValue}" />
<DataGridTemplateColumn>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<CheckBox Name="abcdef"
Content="Please Select" IsChecked="{Binding Path=IsSelected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Checked">
<i:InvokeCommandAction CommandParameter="{Binding ElementName=abcdef}" Command="{Binding DataContext.CheckCommand, RelativeSource={RelativeSource FindAncestor, AncestorType=DataGrid}}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</CheckBox>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTemplateColumn>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Label Content="{Binding incValue,UpdateSourceTrigger=PropertyChanged}" Background="Red" Foreground="White" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
<Label Content="{Binding UpdatePercentage}" HorizontalAlignment="Left" Background="Blue" Foreground="White" Margin="10,10,0,0" VerticalAlignment="Top" Width="338" Height="30">
</Label>
<Button Content="Button" HorizontalAlignment="Left" Margin="672,20,0,0" VerticalAlignment="Top" Width="75"/>
</Grid>
</Window>
Here is my model
public class tblTransaction
{
public string caseRefNo { get;set;}
public string subjMatr { get; set; }
public int incValue { get; set; }
public DateTime? longTime { get; set; }
public bool IsSelected { get; set; }
}
This is picture of my form
Is it because of DispatcherTimer ? All suggestion are welcome.
df

I think I left a comment in your previous question saying that wrapping your collection to CollectionView is quite smelly.
Anyway, the TransView.Refresh(); is causing the problem in your code.
TransView.Refresh will trigger the "Checked" event for each checked checkbox. The refresh basically asking the wpf engine re-populate all the data to your CollectionView and in turn, each checked checkbox will fire the checked event all over again.
Try setting dispatchTimer.Interval to a much shorter time e.g. 300. You should be able to see the "tick" in checkbox keep flicking becoz of the TransView.Refresh.
For real, I have no idea why you don't just bind your TransList to your DataGrid and called BeginInvoke on UpdateDataGrid method.
To demo how ObservableCollection works
I used the ObservableCollection to re-wrote some part of your code. At least make things better fall in line with MVVM model.
public abstract class ViewModelBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator]
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
public class MainViewModel : ViewModelBase
{
public ObservableCollection<TblTransaction> TransList { get; private set; }
public DispatcherTimer DispatchTimer = new DispatcherTimer();
public MainViewModel()
{
var model = new ObservableCollection<TblTransaction>();
for (int i = 0; i < 5; i++)
{
model.Add(new TblTransaction { CaseRefNo = i.ToString(), IncValue = i, LongTime = DateTime.Now, SubjMatr = i.ToString() });
if (i == 3)
model[i].IsSelected = true;
}
DispatchTimer.Interval = TimeSpan.FromMilliseconds(200);
DispatchTimer.Tick += dispatchTimer_Tick;
TransList = model;
DispatchTimer.Start();
}
private void dispatchTimer_Tick(object sender, EventArgs e)
{
UpdateDataGrid();
}
public void UpdateDataGrid()
{
var ran = new Random();
foreach (var tran in TransList)
tran.IncValue = ran.Next(0, 100);
}
}
public class TblTransaction : ViewModelBase
{
private string caseRefNo;
private string subjMatr;
private int incValue;
private DateTime? longTime;
private bool isSelected;
public DelegateCommand<object> CheckCommand { get; set; }
public TblTransaction()
{
CheckCommand = new DelegateCommand<object>(CheckBoxChecker, (p) => true);
}
private void CheckBoxChecker(object args)
{
//Should Work Here
// Totally not coming to this function
//CheckBox chk = (CheckBox)args;
//string thichintae = chk.Name;
Console.WriteLine(args);
}
public string CaseRefNo
{
get { return caseRefNo; }
set
{
caseRefNo = value;
OnPropertyChanged();
}
}
public string SubjMatr
{
get { return subjMatr; }
set
{
subjMatr = value;
OnPropertyChanged();
}
}
public int IncValue
{
get { return incValue; }
set
{
incValue = value;
OnPropertyChanged();
}
}
public DateTime? LongTime
{
get { return longTime; }
set
{
longTime = value;
OnPropertyChanged();
}
}
public bool IsSelected
{
get { return isSelected; }
set
{
isSelected = value;
OnPropertyChanged();
}
}
}
<Window x:Class="WpfTestProj.MainWindow"
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:WpfTestProj"
xmlns:interact="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
mc:Ignorable="d"
d:DataContext="{d:DesignInstance Type=local:MainViewModel, IsDesignTimeCreatable=False}"
Title="MainWindow" Height="350" Width="525">
<Grid>
<DataGrid HorizontalAlignment="Left" ItemsSource="{Binding TransList}" AutoGenerateColumns="False" Margin="10,62,0,0" VerticalAlignment="Top" Height="497" Width="762">
<DataGrid.Columns>
<DataGridTextColumn Header="caseRefNo" Binding="{Binding CaseRefNo}" />
<DataGridTextColumn Header="subjMatr" Binding="{Binding SubjMatr}" />
<DataGridTextColumn Header="Download %" Binding="{Binding IncValue}" />
<DataGridTemplateColumn>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<CheckBox
Content="Please Select" IsChecked="{Binding Path=IsSelected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}">
<interact:Interaction.Triggers>
<interact:EventTrigger EventName="Checked">
<interact:InvokeCommandAction CommandParameter="{Binding Path=CaseRefNo}" Command="{Binding Path=CheckCommand}" />
</interact:EventTrigger>
</interact:Interaction.Triggers>
</CheckBox>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTemplateColumn>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Label Content="{Binding IncValue, UpdateSourceTrigger=PropertyChanged}" Background="Red" Foreground="White" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
<Button Content="Button" HorizontalAlignment="Left" Margin="672,20,0,0" VerticalAlignment="Top" Width="75"/>
</Grid>

How to bind to a nested class wpf

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.

Binding ComboBox SelectedItem to Datagrid

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>

We Keep Coding

C# (C-Sharp) is a programming language developed by Microsoft that runs on the .NET Framework.

Updating ComboBox in XAML without Somegrid.Items.Refresh() - c#

Instead of refreshing the grid, remove the current source and set a new source: yourGrid.ItemsSource = null; yourGrid.ItemsSource = yourDataSource;

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How to bind to a nested class wpf

Binding ComboBox SelectedItem to Datagrid

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