WPF Grid Updating Issue - wpf

Question

I am adding an item to my datasource that is bound to a datagrid, but the UI is not updating to show the new item. Here is my code.
DBContainer ctx = new DBContainer();
private void btnAddNewDesignator_Click(object sender, RoutedEventArgs e)
{
DESIGNATOR a = new DESIGNATOR();
a.DesignatorName = txtDesignator.Text;
a.TXFreq = txtTX.Text;
a.RXFreq = txtRX.Text;
ctx.AddToDESIGNATORs(a);
ctx.SaveChanges();
dgDesignators.Items.Refresh();
}
private void btnAddNewDesignator_Loaded(object sender, RoutedEventArgs e)
{
dgDesignators.ItemsSource = ctx.DESIGNATORs;
}
Here is my xaml:
<DataGrid AutoGenerateColumns="False" Height="225" HorizontalAlignment="Left" Margin="56,230,0,0" Name="dgDesignators" VerticalAlignment="Top" Width="602" CanUserAddRows="True" CanUserDeleteRows="True">
<DataGrid.Columns>
<DataGridTextColumn Header="Designator" Binding="{Binding Path=DesignatorName,Mode=OneWay}" />
<DataGridTextColumn Header="TX Frequency" Binding="{Binding Path=TXFreq,Mode=OneWay}" />
<DataGridTextColumn Header="RX Frequency" Binding="{Binding Path=RXFreq,Mode=OneWay}" />
<DataGridTextColumn Header="In Use" />
</DataGrid.Columns>
</DataGrid>
As you can see I am refreshing, I have also tried setting the ItemSource to null first, and then rebinding it, but to no avail. Thanks for your help.

Answer 1

DBContainer ctx = new DBContainer();
private void btnAddNewDesignator_Click(object sender, RoutedEventArgs e)
{
DESIGNATOR a = new DESIGNATOR();
a.DesignatorName = txtDesignator.Text;
a.TXFreq = txtTX.Text;
a.RXFreq = txtRX.Text;
ctx.AddToDESIGNATORs(a);
ctx.SaveChanges();
dgDesignators.Items.Refresh();
}
private void btnAddNewDesignator_Loaded(object sender, RoutedEventArgs e)
{
dgDesignators.ItemsSource = ctx.DESIGNATORs.ToList();
}
I don't suggest this kind of code in WPF, try doing it in an MVVM pattern and it should be easier to implement and all you need to do is make a class that will act as the DataContext of the DataGrid and make that class implement INotifyPropertyChange

Answer 2

Button Event Handler:
private void btnAddNewDesignator_Click(object sender, RoutedEventArgs e)
{
DESIGNATOR a = new DESIGNATOR();
a.DesignatorName = txtDesignator.Text;
a.TXFreq = txtTX.Text;
a.RXFreq = txtRX.Text;
ctx.AddToDESIGNATORs(a);
ctx.SaveChanges();
designatorDataSource = ctx.DESIGNATOR.ToList();
}
ItemsSourceProperty:
private List<DESIGNATOR> _designatorDataSource = new List<DESIGNATOR>();
public List<DESIGNATOR designatorDataSource {
get {
return _designatorDataSource;
}
set {
_designatorDataSource = value;
OnPropertyChanged("designatorDataSource");
}
}
Then you bind your DataGrid:
<DataGrid Name="dgDesignators" ItemsSource={Binding designatorDataSource, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}">
</DataGrid>
Edit:
Adding INotifyPropertyChanged, have your class extend INotifyPropertyChanged.
Example:
using System.ComponentModel;
public class MyClass : Window, INotifyPropertyChanged
Add the Property Change Event
#region Property Change Event
/// <summary>
/// Occurs when a property is changed
/// </summary>
public event PropertyChangedEventHandler PropertyChanged;
/// <summary>
/// Raises the <see cref="PropertyChanged"/> for a given
/// property.
/// </summary>
/// <param name="propertyName"></param>
protected void OnPropertyChanged(String propertyName) {
// Get the handler
PropertyChangedEventHandler handler = this.PropertyChanged;
// Check that the event handler is not null
if(null != handler) {
// Fire the event
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion