wpf datagrid : 在 wpf 中創建一個 DatagridNumericColumn

Question

我有一個要求，我想制作一個僅接受數值（整數）的數據網格列，當用戶輸入數字以外的其他內容處理文本框時。我嘗試了很多網頁，我厭倦了這些，我非常感謝任何有幫助的人。

"

Answer 1

根據@nit建議，您可以創建自己的類，這些類派生自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，將OnPreviewTextInput方法注冊到編輯TextBox PreviewTextInput事件，在該事件中驗證數值。

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>

希望這可以幫助

Answer 2

如果您不想顯示任何驗證錯誤並且只想阻止任何非數字值，那么您可以創建DataGridTemplateColumn並在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>

和在PreviewTextInput文本框組e.Handled = true ，如果值小於整數其他：

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

Answer 3

我來到這里尋找解決同一問題的方法：將DataGrid上的單元格輸入約束為數字。 但接受的答案對我不起作用。 以下做了：

1. 對於DataGrid為PreparingForCellEdit添加一個事件處理程序。
2. 在該事件處理程序中，將EditingElement轉換為TextBox ，並將PreviewTextInput的事件處理程序添加到TextBox 。
3. 在PreviewTextInput事件處理程序中，如果不允許輸入，則將e.Handled設置為true。

如果用戶單擊要編輯的單元格，則上述步驟有效。 但是，如果單元格未處於編輯模式，則不會調用PreparingForCellEdit事件。 在這種情況下執行驗證：

1. 事件處理程序添加到DataGrid的PreviewTextInput 。
2. 在該事件處理程序中，安全地將e.OriginalSource轉換為DataGridCell （退出，如果它不是DataGridCell ），檢查DataGridCell's IsEditing屬性，如果單元格未編輯，則將e.Handled設置為true。

上述效果是用戶必須單擊進入單元格以編輯其內容，因此，對於單元格內容的所有更改，將調用上面的PreparingForCellEdit / PreviewTextInput組合。

Answer 4

請改用TryParse ，這有助於將輸入值僅限制為整數。

    /// <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 5

只是為了擴展@ Omribitan的答案，以下是添加了數據Paste防護的解決方案：

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 6

無論它值多少，這就是我如何解決它。 此解決方案允許您在驗證輸入時指定各種選項，允許使用字符串格式（例如，數據網格中的“$ 15.00”）等等。

Binding類本身提供的空值和字符串格式不足以在單元格可編輯時無法正常操作，因此該類將覆蓋它。 這樣做是因為它使用了我已經使用了很長時間的另一個類： TextBoxInputBehavior ，它對我來說是一個非常寶貴的資產，它最初來自WPF - TextBox輸入行為博客文章，盡管這里的版本似乎更老了（但經過充分測試）。 所以我做了什么我只是將我已經在TextBox上的現有功能轉移到了我的自定義列，因此我在兩者中都有相同的行為。 這不是很整潔嗎？

這是自定義列的代碼：

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);
    }
}

我做的是我偷看了DataGridTextColumn的源代碼並以幾乎相同的方式處理TextBox創建加上我將自定義行為附加到TextBox。

這是我附加的行為的代碼（這是您可以在任何TextBox上使用的行為）：

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;
    }
}

以上行為類的所有良好功勞歸於盲目，我只是隨着時間推移而調整它。 檢查他的博客后，我看到他有一個更新的版本，所以你可以檢查出來。 我很高興發現我也可以在DataGrid上使用他的行為！

這個解決方案工作得很好，您可以通過鼠標/鍵盤正確編輯單元格，正確粘貼內容，使用任何綁定源更新觸發器，使用任何字符串格式等 - 它只是工作。

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}" />

希望這有助於某人。

Answer 7

我繼續使用 Omris 方法，但是我希望能夠在輸入后刪除單元格值，以防他們想清除它

我這樣做的方法是覆蓋 CommitCellEdit 方法並使字符串為空而不是空白。 我也用十進制？ 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;
        }
    }
}