Question

您可以通过以下代码一个来增加和减少数字。

以下代码是okey。

<Window x:Class="WpfApplication1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="400">
<Grid>
    <RepeatButton Width="100" Height="40"  HorizontalAlignment="Left" Name="btnRemove" Content="Remove" Click="btnRemove_Click" />
    <TextBox Width="150" Height="40" Name="txtDisplay" TextAlignment="Center" Text="5000" MaxLength="5" />
    <RepeatButton Width="100" Height="40" HorizontalAlignment="Right" Name="btnAdd" Content="Add" Click="btnAdd_Click" />
</Grid>
</Window>

...

Namespace WpfApplication1

Partial Public Class MainWindow

    Public counter As Integer = 5000

    Private Sub btnAdd_Click(sender As Object, e As RoutedEventArgs)
        txtDisplay.Text = (System.Threading.Interlocked.Increment(counter)).ToString()
    End Sub

    Private Sub btnRemove_Click(sender As Object, e As RoutedEventArgs)
        txtDisplay.Text = (System.Threading.Interlocked.Decrement(counter)).ToString()
    End Sub

End Class

End Namespace

问题：

如何按百增加和减少数字？

Answer 1

所以你的问题是关于线程安全递增/递减？您可以使用Interlocked.Add：

Private Sub btnAdd_Click(sender As Object, e As RoutedEventArgs)
    txtDisplay.Text = System.Threading.Interlocked.Add(counter, 100).ToString()
End Sub

Private Sub btnRemove_Click(sender As Object, e As RoutedEventArgs)
    txtDisplay.Text = System.Threading.Interlocked.Add(counter, -100).ToString()
End Sub

Answer 2

这个怎么样？

Private Sub btnAdd_Click(sender As Object, e As RoutedEventArgs)
    counter += 100
    If (counter > 6000) Then
        counter = 6000
    End If
    txtDisplay.Text = counter.ToString()
End Sub

Private Sub btnRemove_Click(sender As Object, e As RoutedEventArgs)
    counter -= 100
    If (counter < 0) Then
        counter = 0
    End If
    txtDisplay.Text = counter.ToString()
End Sub

这里没有理由使用System.Threading.Interlocked.Increment，因为事件处理程序总是在同一个线程上执行。

如何通过RepeatButton增加和减少数百？

2 个答案: