WPF C＃Datagrid不添加行，除非我有另一个控件来获得焦点

Question

I have a empty datagrid bound to an observable collection of custom objects. When I try to create a new row through the UI I get a new row but it never seems to commit the new row unless I have another control for the UI to give focus to. Without the other control I can just tab through each column of the new row and it is an endless circle. If I change the Textblock to a textbox then I can tab to the textbox and I get the new row.

Below is all of my code and XAML.

XAML:

<Window x:Class="WPFDatagridTesting.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" Loaded="Window_Loaded">
    <Window.Resources>
        <CollectionViewSource x:Name="MultiplierCollection" x:Key="MultiplierCollection"></CollectionViewSource>
    </Window.Resources>
    <Grid>
        <DockPanel LastChildFill="True">
            <TextBlock  Name="NumberTotal" DockPanel.Dock="Bottom">test</TextBlock>
            <DataGrid Name="TestGrid"


                      CanUserAddRows="True"
                      AutoGenerateColumns="False"
                      CanUserDeleteRows="True"
                      CanUserReorderColumns="False"
                      ItemsSource="{Binding Source={StaticResource MultiplierCollection}}" IsSynchronizedWithCurrentItem="True" AlternatingRowBackground="#FFF7EF9E" AlternationCount="1" SelectionUnit="CellOrRowHeader" ClipboardCopyMode="IncludeHeader">
                <DataGrid.Resources>
                    <Style x:Key="errorStyle" TargetType="{x:Type TextBox}">
                        <Setter Property="Padding" Value="-2"/>
                        <Style.Triggers>
                            <Trigger Property="Validation.HasError" Value="True">
                                <Setter Property="Background" Value="Red"/>
                                <Setter Property="ToolTip" 
                Value="{Binding RelativeSource={RelativeSource Self},
                  Path=(Validation.Errors)[0].ErrorContent}"/>
                            </Trigger>
                        </Style.Triggers>
                    </Style>
                </DataGrid.Resources>
                <DataGrid.Columns>
                    <DataGridTextColumn  EditingElementStyle="{StaticResource errorStyle}" Binding="{Binding BaseNumber,ValidatesOnDataErrors=True,ValidatesOnExceptions=True,  Mode=TwoWay,NotifyOnSourceUpdated=true, UpdateSourceTrigger=LostFocus}" Header="Base Number"></DataGridTextColumn>
                    <DataGridTextColumn EditingElementStyle="{StaticResource errorStyle}" Binding="{Binding Multiplier,ValidatesOnDataErrors=True,ValidatesOnExceptions=True,  Mode=TwoWay,NotifyOnSourceUpdated=true,UpdateSourceTrigger=LostFocus}" Header="Multiplier"></DataGridTextColumn>
                    <DataGridTextColumn EditingElementStyle="{StaticResource errorStyle}" Binding="{Binding Result,ValidatesOnDataErrors=True,ValidatesOnExceptions=True, Mode=OneWay,NotifyOnSourceUpdated=true,UpdateSourceTrigger=LostFocus}" Header="Result"></DataGridTextColumn>
                </DataGrid.Columns>
            </DataGrid>

        </DockPanel>
    </Grid>
</Window>

Code-Behind:

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using WPFDatagridTesting.CustomObjects;

namespace WPFDatagridTesting
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        MultiplierObservableCollection mycollection = new MultiplierObservableCollection();
        System.Windows.Data.CollectionViewSource MultiplierCollection;

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {

            try
            {


           mycollection = new MultiplierObservableCollection();


            mycollection.TotalResultsChanged +=mycollection_TotalResultsChanged;

            MultiplierCollection = ((System.Windows.Data.CollectionViewSource)(this.FindResource("MultiplierCollection")));

            MultiplierCollection.Source = mycollection.MultiplierClassList;




            }
            catch (Exception)
            {

                throw;
            }
        }

        void mycollection_TotalResultsChanged(object sender, MultiplierCollectionResultsChangedEventArgs e)
        {
            this.NumberTotal.Text = e.MultiplierResults.ToString();
        }


    }
}

Custom Objects:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;

namespace WPFDatagridTesting.CustomObjects
{
    class MultiplierClass : INotifyPropertyChanged
    {

        protected virtual void Changed(string PropertyName)
        {
            PropertyChangedEventHandler handler = PropertyChanged;
            if (handler != null)
            {
                handler(this, new PropertyChangedEventArgs(PropertyName));

            }

        }

        public event PropertyChangedEventHandler PropertyChanged;

        public MultiplierClass()
        {

        }


        private int _BaseNumber;
        public int BaseNumber
        {
            get
            {

                return _BaseNumber;

            }

            set
            {
                if (_BaseNumber != value)
                {
                    _BaseNumber = value;
                    Changed("BaseNumber");
                    Changed("Result");


                }

            }

        }

        private int _Multiplier;
        public int Multiplier
        {
            get
            {

                return _Multiplier;

            }

            set
            {
                if (_Multiplier != value)
                {
                    _Multiplier = value;
                    Changed("Multiplier");
                    Changed("Result");

                }

            }

        }

        public int Result
        {
            get
            {

                return _BaseNumber * _Multiplier;

            }

        }



    }
}


using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;

namespace WPFDatagridTesting.CustomObjects
{
    class MultiplierObservableCollection : ObservableCollection<MultiplierClass>
    {

        public ObservableCollection<MultiplierClass> MultiplierClassList { get; set; }

        public MultiplierObservableCollection() : base()
        {

            MultiplierClassList = new ObservableCollection<MultiplierClass>();

            MultiplierClassList.CollectionChanged += MultiplierClassList_CollectionChanged;




        }

        void MultiplierClassList_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
            if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
            {
                foreach (MultiplierClass item in e.NewItems)
                {
                    //Added items
                    item.PropertyChanged += myNewClass_PropertyChanged;

                } 


            }

            if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Remove)
            {
                MultiplierClass myNewClass = new MultiplierClass();

                myNewClass.PropertyChanged -= myNewClass_PropertyChanged;

            }

            myNewClass_PropertyChanged(this, null);


        }

        void myNewClass_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
        {
            MultiplierCollectionResultsChangedEventArgs myEventArgs = new MultiplierCollectionResultsChangedEventArgs();

            myEventArgs.MultiplierResults = this.MultiplierClassList.Sum(mc => mc.Result);



                EventHandler<MultiplierCollectionResultsChangedEventArgs> handler = TotalResultsChanged;
                if (handler != null)
                {
                    handler(this, myEventArgs);
                }


        }


        public event EventHandler<MultiplierCollectionResultsChangedEventArgs> TotalResultsChanged;




    }

    public class MultiplierCollectionResultsChangedEventArgs : EventArgs
    {
        public int MultiplierResults { get; set; }
    }

}

Answer 1

You might need to change

ItemsSource="{Binding Source={StaticResource MultiplierCollection}}"

to

ItemsSource="{Binding Source={StaticResource MultiplierCollection, NotifyOnTargetUpdated=True, NotifyOnSourceUpdated=True}}"