我允许数字键盘号码和退格:

    private void TextBox_PreviewKeyDown(object sender, KeyEventArgs e)
    {
        int key = (int)e.Key;

        e.Handled = !(key >= 34 && key <= 43 || 
                      key >= 74 && key <= 83 || 
                      key == 2);
    }

我允许数字键盘号码和退格:

    private void TextBox_PreviewKeyDown(object sender, KeyEventArgs e)
    {
        int key = (int)e.Key;

        e.Handled = !(key >= 34 && key <= 43 || 
                      key >= 74 && key <= 83 || 
                      key == 2);
    }

当检查数字值时，您可以使用VisualBasic。IsNumeric函数。

下面的代码创建了一个控件，你将能够像正常的文本框一样使用，但它只会把一个正的双精度作为输入:

在XAML中，你可以这样使用这个控件:

<local:UnsignedDoubleBox/>

在c#代码中，在当前命名空间中添加以下内容:

public class UnsignedDoubleBox : TextBox
    {
        public UnsignedDoubleBox()
        {
            this.PreviewTextInput += defaultPreviewTextInput;
            DataObject.AddPastingHandler(this, defaultTextBoxPasting);
        }

        private bool IsTextAllowed(TextBox textBox, String text)
        {
            //source: https://stackoverflow.com/questions/23397195/in-wpf-does-previewtextinput-always-give-a-single-character-only#comment89374810_23406386
            String newText = textBox.Text.Insert(textBox.CaretIndex, text);
            double res;
            return double.TryParse(newText, out res) && res >= 0;
        }
        //source: https://stackoverflow.com/a/1268648/13093413
        private void defaultTextBoxPasting(object sender, DataObjectPastingEventArgs e)
        {
            if (e.DataObject.GetDataPresent(typeof(String)))
            {
                String text = (String)e.DataObject.GetData(typeof(String));

                if (!IsTextAllowed((TextBox)sender, text))
                {
                    e.CancelCommand();
                }
            }
            else
            {
                e.CancelCommand();
            }
        }

        private void defaultPreviewTextInput(object sender, TextCompositionEventArgs e)
        {

            if (IsTextAllowed((TextBox)sender, e.Text))
            {
                e.Handled = false;
            }
            else
            {
                e.Handled = true;
            }
        }

    }

这是我用来获得一个接受数字和小数点的WPF文本框:

class numericTextBox : TextBox
{
    protected override void OnKeyDown(KeyEventArgs e)
    {
        bool b = false;
        switch (e.Key)
        {
            case Key.Back: b = true; break;
            case Key.D0: b = true; break;
            case Key.D1: b = true; break;
            case Key.D2: b = true; break;
            case Key.D3: b = true; break;
            case Key.D4: b = true; break;
            case Key.D5: b = true; break;
            case Key.D6: b = true; break;
            case Key.D7: b = true; break;
            case Key.D8: b = true; break;
            case Key.D9: b = true; break;
            case Key.OemPeriod: b = true; break;
        }
        if (b == false)
        {
            e.Handled = true;
        }
        base.OnKeyDown(e);
    }
}

将代码放在一个新的类文件中，添加

using System.Windows.Controls;
using System.Windows.Input;

并构建解决方案。numericTextBox控件将出现在工具箱的顶部。

Use:

Private Sub DetailTextBox_PreviewTextInput( _
  ByVal sender As Object, _
  ByVal e As System.Windows.Input.TextCompositionEventArgs) _
  Handles DetailTextBox.PreviewTextInput

    If _IsANumber Then
        If Not Char.IsNumber(e.Text) Then
            e.Handled = True
        End If
    End If
End Sub