WPF选择DataGrid中的所有CheckBox

Question

我正在尝试在DataGrid中选择所有CheckBox,但我没有使用此代码获得任何结果

这是我在单击主CheckBox时调用的函数

private void CheckUnCheckAll(object sender, RoutedEventArgs e)
{
    CheckBox chkSelectAll = ((CheckBox)sender);
    if (chkSelectAll.IsChecked == true)
    {
        dgUsers.Items.OfType<CheckBox>().ToList().ForEach(x => x.IsChecked = true);
    }
    else
    {
        dgUsers.Items.OfType<CheckBox>().ToList().ForEach(x => x.IsChecked = false);
    }
}

dgUsers是DataGrid,但我发现任何复选框都找到了.

这是我正在使用的XAML在数据网格中创建CheckBox

<DataGrid.Columns>
    <DataGridCheckBoxColumn x:Name="col0" HeaderStyle="{StaticResource ColumnHeaderGripperStyle}">
         <DataGridCheckBoxColumn.HeaderTemplate>
              <DataTemplate>
                   <CheckBox Click="CheckUnCheckAll" >
                   </CheckBox>
              </DataTemplate>
         </DataGridCheckBoxColumn.HeaderTemplate>
    </DataGridCheckBoxColumn>
<DataGrid.Columns>

这是我的DataGrid的图片

有没有办法以编程方式选择所有复选框？

编辑 我已经尝试按照这个步骤

你可以看到我的代码是相同的,但对我不起作用

Answer 1

TLDR; 这就是你想要的,代码如下:

执行此操作的适当位置将在ViewModel中.您的CheckBox可以有三种状态,所有这些状态都要使用:

1. 已选中 - 已检查每个项目
2. 未选中 - 未选中任何项目
3. 不确定 - 有些项目已经过检查,有些则没有

每当检查/取消选中项目时,您都希望更新CheckBox,并在更改CheckBox时更新所有项目 - 仅实现此方法会使CheckBox处于无效状态,这可能会对用户体验产生负面影响.我的建议:一路走好并妥善实施.要做到这一点,你需要知道导致更改的因素 - 条目的CheckBox或标题中的CheckBox.

我将如何做到这一点:

首先你需要一个ViewModel作为你的项目,我在这里使用了一个非常简单的只包含IsChecked属性.

public class Entry : INotifyPropertyChanged
{
    private bool _isChecked;

    public bool IsChecked
    {
        get => _isChecked;
        set
        {
            if (value == _isChecked) return;
            _isChecked = value;
            OnPropertyChanged();
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    [NotifyPropertyChangedInvocator]
    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

您的主ViewModel将包含所有项目的集合.每当项目的IsChecked属性发生变化时,您都必须检查是否已选中/取消选中所有项目,并更新标题中的CheckBox(或更确切地说是其数据源的值).

public class ViewModel : INotifyPropertyChanged
{
    public List<Entry> Entries
    {
        get => _entries;
        set
        {
            if (Equals(value, _entries)) return;
            _entries = value;
            OnPropertyChanged();
        }
    }

    public ViewModel()
    {
        // Just some demo data
        Entries = new List<Entry>
        {
            new Entry(),
            new Entry(),
            new Entry(),
            new Entry()
        };

        // Make sure to listen to changes. 
        // If you add/remove items, don't forgat to add/remove the event handlers too
        foreach (Entry entry in Entries)
        {
            entry.PropertyChanged += EntryOnPropertyChanged;
        }
    }

    private void EntryOnPropertyChanged(object sender, PropertyChangedEventArgs args)
    {
        // Only re-check if the IsChecked property changed
        if(args.PropertyName == nameof(Entry.IsChecked))
            RecheckAllSelected();
    }

    private void AllSelectedChanged()
    {
        // Has this change been caused by some other change?
        // return so we don't mess things up
        if (_allSelectedChanging) return;

        try
        {
            _allSelectedChanging = true;

            // this can of course be simplified
            if (AllSelected == true)
            {
                foreach (Entry kommune in Entries)
                    kommune.IsChecked = true;
            }
            else if (AllSelected == false)
            {
                foreach (Entry kommune in Entries)
                    kommune.IsChecked = false;
            }
        }
        finally
        {
            _allSelectedChanging = false;
        }
    }

    private void RecheckAllSelected()
    {
        // Has this change been caused by some other change?
        // return so we don't mess things up
        if (_allSelectedChanging) return;

        try
        {
            _allSelectedChanging = true;

            if (Entries.All(e => e.IsChecked))
                AllSelected = true;
            else if (Entries.All(e => !e.IsChecked))
                AllSelected = false;
            else
                AllSelected = null;
        }
        finally
        {
            _allSelectedChanging = false;
        }
    }

    public bool? AllSelected
    {
        get => _allSelected;
        set
        {
            if (value == _allSelected) return;
            _allSelected = value;

            // Set all other CheckBoxes
            AllSelectedChanged();
            OnPropertyChanged();
        }
    }

    private bool _allSelectedChanging;
    private List<Entry> _entries;
    private bool? _allSelected;
    public event PropertyChangedEventHandler PropertyChanged;

    [NotifyPropertyChangedInvocator]
    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

演示XAML:

<DataGrid ItemsSource="{Binding Entries}" AutoGenerateColumns="False" IsReadOnly="False" CanUserAddRows="False">
    <DataGrid.Columns>
        <DataGridCheckBoxColumn Binding="{Binding IsChecked, UpdateSourceTrigger=PropertyChanged}">
            <DataGridCheckBoxColumn.HeaderTemplate>
                <DataTemplate>
                    <CheckBox IsChecked="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=local:MainWindow}, Path=ViewModel.AllSelected}">Select All</CheckBox>
                </DataTemplate>
            </DataGridCheckBoxColumn.HeaderTemplate>
        </DataGridCheckBoxColumn>
    </DataGrid.Columns>
</DataGrid>

Answer 2

这是基于@Manfred解决方案的修改。我用Command而不是event.

XAML：

<DataGrid ItemsSource="{Binding Students}" AutoGenerateColumns="True" CanUserAddRows="False">
    <DataGrid.Columns>
        <DataGridTemplateColumn>
            <DataGridTemplateColumn.HeaderTemplate>
                <DataTemplate>
                    <CheckBox IsChecked="{Binding DataContext.IsAllSelected, RelativeSource={RelativeSource AncestorType=DataGrid}}" Command="{Binding DataContext.CheckAllStudentsCommand, RelativeSource={RelativeSource AncestorType=DataGrid}}" />
                </DataTemplate>
            </DataGridTemplateColumn.HeaderTemplate>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <CheckBox IsChecked="{Binding IsChecked, UpdateSourceTrigger=PropertyChanged}" Command="{Binding DataContext.CheckStudentCommand, RelativeSource={RelativeSource AncestorType=DataGrid}}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

视图模型：

public class MainWindowViewModel : INotifyPropertyChanged
{
    private List<Student> students;

    public List<Student> Students
    {
        get { return students; }
        set { students = value; OnPropertyChanged(); }
    }

    private bool? isAllSelected;

    public bool? IsAllSelected
    {
        get { return isAllSelected; }
        set { isAllSelected = value; OnPropertyChanged(); }
    }

    public RelayCommand CheckStudentCommand { get; private set; }
    public RelayCommand CheckAllStudentsCommand { get; private set; }

    public MainWindowViewModel()
    {
        Students = new List<Student>() { new Student { Name = "Walter" }, new Student { Name = "Jenny" }, new Student { Name = "Joe" } };
        CheckStudentCommand = new RelayCommand(OnCheckStudent);
        CheckAllStudentsCommand = new RelayCommand(OnCheckAllStudents);
        IsAllSelected = false;
    }

    private void OnCheckAllStudents()
    {
        if (IsAllSelected == true)
            Students.ForEach(x => x.IsChecked = true);
        else
            Students.ForEach(x => x.IsChecked = false);
    }

    private void OnCheckStudent()
    {
        if (Students.All(x => x.IsChecked))
            IsAllSelected = true;
        else if (Students.All(x => !x.IsChecked))
            IsAllSelected = false;
        else
            IsAllSelected = null;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

源代码可以在这里找到