WPF選擇DataGrid中的所有CheckBox

Question

我正在嘗試在DataGrid中選擇所有CheckBox，但我沒有使用此代碼獲得任何結果

這是我在單擊主CheckBox時調用的函數

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，但我發現任何復選框都找到了。

這是我正在使用的XAML在數據網格中創建CheckBox

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

這是我的DataGrid的圖片

有沒有辦法以編程方式選擇所有復選框？

編輯我已經嘗試按照這個步驟

你可以看到我的代碼是相同的，但對我不起作用

Answer 1

TLDR; 這就是你想要的，代碼如下：

執行此操作的適當位置將在ViewModel中。 您的CheckBox可以有三種狀態，所有這些狀態都要使用：

1. 已選中 - 已檢查每個項目
2. 未選中 - 未選中任何項目
3. 不確定 - 有些項目已經過檢查，有些則沒有

每當檢查/取消選中項目時，您都希望更新CheckBox，並在更改CheckBox時更新所有項目 - 僅實現此方法會使CheckBox處於無效狀態，這可能會對用戶體驗產生負面影響。 我的建議：一路走好並妥善實施。 要做到這一點，你需要知道導致更改的因素 - 條目的CheckBox或標題中的CheckBox。

我將如何做到這一點：

首先，你需要一個ViewModel作為你的項目，我在這里使用了一個非常簡單的，只包含IsChecked屬性。

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將包含所有項目的集合。 每當項目的IsChecked屬性發生更改時，您必須檢查是否已選中/取消選中所有項目，並更新標題中的CheckBox（或更確切地說是其數據源的值）。

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

你在你的例子中做的是迭代數據項而不是通過控件（我想你沒有像ItemsSource那樣的控件）。
在您發布的鏈接中， YourClass是ViewModel中的類，網格行的數據對象。

這個應該可以使用最少的代碼更改（但我更喜歡在ViewModel中處理它與CheckUncheckCommand + IsChecked綁定到CommandParameter ）：

<DataGridCheckBoxColumn x:Name="col0" HeaderStyle="{StaticResource ColumnHeaderGripperStyle}" DisplayIndex="0">

private void CheckUnCheckAll(object sender, RoutedEventArgs e)
{
    var chkSelectAll = sender as CheckBox;
    var firstCol = dgUsers.Columns.OfType<DataGridCheckBoxColumn>().FirstOrDefault(c => c.DisplayIndex == 0);
    if (chkSelectAll == null || firstCol == null || dgUsers?.Items == null)
    {
        return;
    }
    foreach (var item in dgUsers.Items)
    {
        var chBx = firstCol.GetCellContent(item) as CheckBox;
        if (chBx == null)
        {
            continue;
        }
        chBx.IsChecked = chkSelectAll.IsChecked;
    }
}

Answer 3

這是基於@Manfred 解決方案的修改。 我使用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>

視圖模型：

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));
    }
}

源代碼可在此處獲得