c# - wpf datagrid : 在 wpf 中创建一个 DatagridNumericColumn

Question

我有一个要求，当用户输入除数字以外的其他内容处理文本框时，我想制作一个仅接受数值（整数）的 datagridcolumn 。我尝试了很多网页，我厌倦了这些，我非常感谢任何有帮助的人。

Answer 1

根据@nit 的建议，您可以创建自己的类，DataGridTextColumn如下所示：

public class DataGridNumericColumn : DataGridTextColumn
{
    protected override object PrepareCellForEdit(System.Windows.FrameworkElement editingElement, System.Windows.RoutedEventArgs editingEventArgs)
    {
        TextBox edit = editingElement as TextBox;
        edit.PreviewTextInput += OnPreviewTextInput;

        return base.PrepareCellForEdit(editingElement, editingEventArgs);
    }

    void OnPreviewTextInput(object sender, System.Windows.Input.TextCompositionEventArgs e)
    {
        try
        {
            Convert.ToInt32(e.Text);
        }
        catch
        {
            // Show some kind of error message if you want

            // Set handled to true
            e.Handled = true;
        }
    }
}

在PrepareCellForEdit方法中，您将该方法注册OnPreviewTextInput到编辑TextBox PreviewTextInput事件，您可以在其中验证数值。

在 xaml 中，您只需使用它：

    <DataGrid ItemsSource="{Binding SomeCollection}">
        <DataGrid.Columns>
            <DataGridTextColumn Binding="{Binding NonNumericProperty}"/>
            <local:DataGridNumericColumn Binding="{Binding NumericProperty}"/>
        </DataGrid.Columns>
    </DataGrid>

希望这可以帮助

Answer 2

如果您不想显示任何验证错误并且只想阻止任何非数字值，那么您可以创建DataGridTemplateColumn和CellEditingTemplate使用TextBox.

                <DataGridTemplateColumn Width="100*">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding Path=NumericProperty}"/>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                    <DataGridTemplateColumn.CellEditingTemplate>
                        <DataTemplate>
                            <TextBox PreviewTextInput="TextBox_PreviewTextInput" Text="{Binding Path=NumericProperty}"/>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellEditingTemplate>
                </DataGridTemplateColumn>

如果值不是整数，则在PreviewTextInputTextBox 集合中：e.Handled = true

       private void TextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
        {
            try
            {
                Convert.ToInt32(e.Text);
            }
            catch
            {
                e.Handled = true;
            }
        }

Answer 3

我来这里是为了寻找相同问题的解决方案：将 a 上的单元格的输入限制为DataGrid数字。但是接受的答案对我不起作用。以下做了：

1. 为. DataGrid_PreparingForCellEdit
2. 在该事件处理程序中，将EditingElement转换为 aTextBox并将事件处理程序添加PreviewTextInput到TextBox.
3. 在PreviewTextInput事件处理程序中设置e.Handled为 true，如果不应该允许输入。

如果用户单击要编辑的单元格，则上述步骤有效。但是，如果单元格未处于编辑模式，PreparingForCellEdit则不会调用该事件。在这种情况下执行验证：

1. 将事件处理程序添加到DataGridfor PreviewTextInput。
2. 在该事件处理程序中，安全地e.OriginalSource转换为 a DataGridCell（退出，如果它不是 a DataGridCell），检查DataGridCell's IsEditing属性，如果单元格未编辑，则设置e.Handled为 true。

上述效果是用户必须单击单元格才能编辑其内容，因此，将对单元格内容的所有更改调用上面的PreparingForCellEdit/组合。PreviewTextInput

Answer 4

不管它值多少钱，这就是我解决它的方法。此解决方案允许您在验证输入时指定各种选项，允许使用字符串格式（例如，数据网格中的“$15.00”）等等。

类本身提供的空值和字符串格式是Binding不够的，因为当单元格可编辑时它们都不能正确操作，所以这个类覆盖了它。它的作用是它使用了另一个我已经使用了很长时间的类：TextBoxInputBehavior，它对我来说是无价的资产，它最初来自WPF – TextBox Input Behavior博客文章，尽管这里的版本似乎要旧得多（但测试良好）。所以我所做的只是将我在 TextBoxes 上已有的现有功能转移到我的自定义列中，因此我在两者中都有相同的行为。这不是很整洁吗？

这是自定义列的代码：

public class DataGridNumberColumn : DataGridTextColumn
{
    private TextBoxInputBehavior _behavior;

    protected override FrameworkElement GenerateElement(DataGridCell cell, object dataItem)
    {
        var element = base.GenerateElement(cell, dataItem);

        // A clever workaround the StringFormat issue with the Binding set to the 'Binding' property. If you use StringFormat it
        // will only work in edit mode if you changed the value, otherwise it will retain formatting when you enter editing.
        if (!string.IsNullOrEmpty(StringFormat))
        {
            BindingOperations.ClearBinding(element, TextBlock.TextProperty);
            BindingOperations.SetBinding(element, FrameworkElement.TagProperty, Binding);
            BindingOperations.SetBinding(element,
                TextBlock.TextProperty,
                new Binding
                {
                    Source = element,
                    Path = new PropertyPath("Tag"),
                    StringFormat = StringFormat
                });
        }

        return element;
    }

    protected override object PrepareCellForEdit(FrameworkElement editingElement, RoutedEventArgs editingEventArgs)
    {
        if (!(editingElement is TextBox textBox))
            return null;

        var originalText = textBox.Text;

        _behavior = new TextBoxInputBehavior
        {
            IsNumeric = true,
            EmptyValue = EmptyValue,
            IsInteger = IsInteger
        };

        _behavior.Attach(textBox);

        textBox.Focus();

        if (editingEventArgs is TextCompositionEventArgs compositionArgs) // User has activated editing by already typing something
        {
            if (compositionArgs.Text == "\b") // Backspace, it should 'clear' the cell
            {
                textBox.Text = EmptyValue;
                textBox.SelectAll();
                return originalText;
            }

            if (_behavior.ValidateText(compositionArgs.Text))
            {
                textBox.Text = compositionArgs.Text;
                textBox.Select(textBox.Text.Length, 0);
                return originalText;
            }
        }

        if (!(editingEventArgs is MouseButtonEventArgs) || !PlaceCaretOnTextBox(textBox, Mouse.GetPosition(textBox)))
            textBox.SelectAll();

        return originalText;
    }

    private static bool PlaceCaretOnTextBox(TextBox textBox, Point position)
    {
        int characterIndexFromPoint = textBox.GetCharacterIndexFromPoint(position, false);
        if (characterIndexFromPoint < 0)
            return false;
        textBox.Select(characterIndexFromPoint, 0);
        return true;
    }

    protected override void CancelCellEdit(FrameworkElement editingElement, object uneditedValue)
    {
        UnwireTextBox();
        base.CancelCellEdit(editingElement, uneditedValue);
    }

    protected override bool CommitCellEdit(FrameworkElement editingElement)
    {
        UnwireTextBox();
        return base.CommitCellEdit(editingElement);
    }

    private void UnwireTextBox() => _behavior.Detach();

    public static readonly DependencyProperty EmptyValueProperty = DependencyProperty.Register(
        nameof(EmptyValue),
        typeof(string),
        typeof(DataGridNumberColumn));

    public string EmptyValue
    {
        get => (string)GetValue(EmptyValueProperty);
        set => SetValue(EmptyValueProperty, value);
    }

    public static readonly DependencyProperty IsIntegerProperty = DependencyProperty.Register(
        nameof(IsInteger),
        typeof(bool),
        typeof(DataGridNumberColumn));

    public bool IsInteger
    {
        get => (bool)GetValue(IsIntegerProperty);
        set => SetValue(IsIntegerProperty, value);
    }

    public static readonly DependencyProperty StringFormatProperty = DependencyProperty.Register(
        nameof(StringFormat),
        typeof(string),
        typeof(DataGridNumberColumn));

    public string StringFormat
    {
        get => (string) GetValue(StringFormatProperty);
        set => SetValue(StringFormatProperty, value);
    }
}

我所做的是查看源代码并以几乎DataGridTextColumn相同的方式处理文本框的创建，并将自定义行为附加到文本框。

这是我附加的行为代码（这是您可以在任何文本框上使用的行为）：

public class TextBoxInputBehavior : Behavior<TextBox>
{
    #region DependencyProperties

    public static readonly DependencyProperty RegularExpressionProperty = DependencyProperty.Register(
        nameof(RegularExpression), 
        typeof(string), 
        typeof(TextBoxInputBehavior), 
        new FrameworkPropertyMetadata(".*"));

    public string RegularExpression
    {
        get
        {
            if (IsInteger)
                return @"^[0-9\-]+$";
            if (IsNumeric)
                return @"^[0-9.\-]+$";
            return (string)GetValue(RegularExpressionProperty);
        }
        set { SetValue(RegularExpressionProperty, value); }
    }

    public static readonly DependencyProperty MaxLengthProperty = DependencyProperty.Register(
        nameof(MaxLength), 
        typeof(int), 
        typeof(TextBoxInputBehavior),
        new FrameworkPropertyMetadata(int.MinValue));

    public int MaxLength
    {
        get { return (int)GetValue(MaxLengthProperty); }
        set { SetValue(MaxLengthProperty, value); }
    }

    public static readonly DependencyProperty EmptyValueProperty = DependencyProperty.Register(
        nameof(EmptyValue), 
        typeof(string), 
        typeof(TextBoxInputBehavior));

    public string EmptyValue
    {
        get { return (string)GetValue(EmptyValueProperty); }
        set { SetValue(EmptyValueProperty, value); }
    }

    public static readonly DependencyProperty IsNumericProperty = DependencyProperty.Register(
        nameof(IsNumeric), 
        typeof(bool), 
        typeof(TextBoxInputBehavior));

    public bool IsNumeric
    {
        get { return (bool)GetValue(IsNumericProperty); }
        set { SetValue(IsNumericProperty, value); }
    }

    public static readonly DependencyProperty IsIntegerProperty = DependencyProperty.Register(
        nameof(IsInteger),
        typeof(bool),
        typeof(TextBoxInputBehavior));

    public bool IsInteger
    {
        get { return (bool)GetValue(IsIntegerProperty); }
        set
        {
            if (value)
                SetValue(IsNumericProperty, true);
            SetValue(IsIntegerProperty, value);
        }
    }

    public static readonly DependencyProperty AllowSpaceProperty = DependencyProperty.Register(
        nameof(AllowSpace),
        typeof (bool),
        typeof (TextBoxInputBehavior));

    public bool AllowSpace
    {
        get { return (bool) GetValue(AllowSpaceProperty); }
        set { SetValue(AllowSpaceProperty, value); }
    }

    #endregion

    protected override void OnAttached()
    {
        base.OnAttached();

        AssociatedObject.PreviewTextInput += PreviewTextInputHandler;
        AssociatedObject.PreviewKeyDown += PreviewKeyDownHandler;
        DataObject.AddPastingHandler(AssociatedObject, PastingHandler);
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();

        if (AssociatedObject == null)
            return;

        AssociatedObject.PreviewTextInput -= PreviewTextInputHandler;
        AssociatedObject.PreviewKeyDown -= PreviewKeyDownHandler;
        DataObject.RemovePastingHandler(AssociatedObject, PastingHandler);
    }

    private void PreviewTextInputHandler(object sender, TextCompositionEventArgs e)
    {
        string text;
        if (AssociatedObject.Text.Length < AssociatedObject.CaretIndex)
            text = AssociatedObject.Text;
        else
            text = TreatSelectedText(out var remainingTextAfterRemoveSelection)
                ? remainingTextAfterRemoveSelection.Insert(AssociatedObject.SelectionStart, e.Text)
                : AssociatedObject.Text.Insert(AssociatedObject.CaretIndex, e.Text);
        e.Handled = !ValidateText(text);
    }

    private void PreviewKeyDownHandler(object sender, KeyEventArgs e)
    {
        if (e.Key == Key.Space)
            e.Handled = !AllowSpace;

        if (string.IsNullOrEmpty(EmptyValue))
            return;

        string text = null;

        // Handle the Backspace key
        if (e.Key == Key.Back)
        {
            if (!TreatSelectedText(out text))
            {
                if (AssociatedObject.SelectionStart > 0)
                    text = AssociatedObject.Text.Remove(AssociatedObject.SelectionStart - 1, 1);
            }
        }
        // Handle the Delete key
        else if (e.Key == Key.Delete)
        {
            // If text was selected, delete it
            if (!TreatSelectedText(out text) && AssociatedObject.Text.Length > AssociatedObject.SelectionStart)
            {
                // Otherwise delete next symbol
                text = AssociatedObject.Text.Remove(AssociatedObject.SelectionStart, 1);
            }
        }

        if (text == string.Empty)
        {
            AssociatedObject.Text = EmptyValue;
            if (e.Key == Key.Back)
                AssociatedObject.SelectionStart++;
            e.Handled = true;
        }
    }

    private void PastingHandler(object sender, DataObjectPastingEventArgs e)
    {
        if (e.DataObject.GetDataPresent(DataFormats.Text))
        {
            var text = Convert.ToString(e.DataObject.GetData(DataFormats.Text));

            if (!ValidateText(text))
                e.CancelCommand();
        }
        else
            e.CancelCommand();
    }

    public bool ValidateText(string text)
    {
        return new Regex(RegularExpression, RegexOptions.IgnoreCase).IsMatch(text) && (MaxLength == int.MinValue || text.Length <= MaxLength);
    }

    /// <summary>
    /// Handle text selection.
    /// </summary>
    /// <returns>true if the character was successfully removed; otherwise, false.</returns>
    private bool TreatSelectedText(out string text)
    {
        text = null;
        if (AssociatedObject.SelectionLength <= 0)
            return false;

        var length = AssociatedObject.Text.Length;
        if (AssociatedObject.SelectionStart >= length)
            return true;

        if (AssociatedObject.SelectionStart + AssociatedObject.SelectionLength >= length)
            AssociatedObject.SelectionLength = length - AssociatedObject.SelectionStart;

        text = AssociatedObject.Text.Remove(AssociatedObject.SelectionStart, AssociatedObject.SelectionLength);
        return true;
    }
}

上述 Behavior 课程的所有优点都归功于blindmeis，我只是随着时间的推移对其进行了调整。在查看了他的博客后，我发现他有一个更新的版本，所以你可以查看一下。我很高兴发现我也可以在 DataGrid 上使用他的行为！

该解决方案效果很好，您可以通过鼠标/键盘正确编辑单元格，正确粘贴内容，使用任何绑定源更新触发器，使用任何字符串格式等 - 它可以正常工作。

以下是如何使用它的示例：

    <local:DataGridNumberColumn Header="Nullable Int Currency" IsInteger="True" Binding="{Binding IntegerNullable, TargetNullValue=''}" StringFormat="{}{0:C}" />

希望这可以帮助某人。

Answer 5

相反，这有助于将TryParse输入值限制为仅整数。

    /// <summary>
    /// This class help to create data grid cell which only support interger numbers.
    /// </summary>
    public class DataGridNumericColumn : DataGridTextColumn
    {
        protected override object PrepareCellForEdit(FrameworkElement editingElement, RoutedEventArgs editingEventArgs)
        {
            TextBox edit = editingElement as TextBox;

            if (edit != null) edit.PreviewTextInput += OnPreviewTextInput;

            return base.PrepareCellForEdit(editingElement, editingEventArgs);
        }

        private void OnPreviewTextInput(object sender, System.Windows.Input.TextCompositionEventArgs e)
        {
            int value;

            if (!int.TryParse(e.Text, out value))
                e.Handled = true;
        }
    }

Answer 6

只是为了扩展@Omribitan 的答案，这是Paste添加了数据保护的解决方案：

public class NumericTextColumn : DataGridTextColumn
{
    protected override object PrepareCellForEdit(FrameworkElement editingElement, RoutedEventArgs editingEventArgs)
    {
        var edit = editingElement as TextBox;
        edit.PreviewTextInput += Edit_PreviewTextInput;
        DataObject.AddPastingHandler(edit, OnPaste);
        return base.PrepareCellForEdit(editingElement, editingEventArgs);
    }

    private void OnPaste(object sender, DataObjectPastingEventArgs e)
    {
        var data = e.SourceDataObject.GetData(DataFormats.Text);
        if (!IsDataValid(data)) e.CancelCommand();
    }

    private void Edit_PreviewTextInput(object sender, TextCompositionEventArgs e)
    {
        e.Handled = !IsDataValid(e.Text);
    }

    bool IsDataValid(object data)
    {
        try
        {
            Convert.ToInt32(data);
            return true;
        }
        catch
        {
            return false;
        }
    }
}

Answer 7

我从 Omris 方法继续，但是我希望能够在输入后删除单元格值，以防他们想清除它

我这样做的方法是覆盖 CommitCellEdit 方法并使字符串为空而不是空白。我也使用十进制？就我而言

public class DataGridNumericColumn : DataGridTextColumn
{
    protected override object PrepareCellForEdit(System.Windows.FrameworkElement editingElement, System.Windows.RoutedEventArgs editingEventArgs)
    
    {
        TextBox edit = editingElement as TextBox;
        edit.PreviewTextInput += OnPreviewTextInput;

        return base.PrepareCellForEdit(editingElement, editingEventArgs);
    }

    protected override bool CommitCellEdit(System.Windows.FrameworkElement editingElement)
    {
        TextBox tb = editingElement as TextBox;
        if (string.IsNullOrEmpty(tb.Text))
            tb.Text = null;
        
        return base.CommitCellEdit(editingElement);
    }
    void OnPreviewTextInput(object sender, System.Windows.Input.TextCompositionEventArgs e)
    
    {
        try
        {
            Convert.ToDecimal(e.Text);
        }
        catch
        {
            // Show some kind of error message if you want

            // Set handled to true
            e.Handled = true;
        }
    }
}