计算 ListBoxes 中的两个值的总数？答案

【问题标题】：Calculate total of two values in ListBoxes?计算 ListBoxes 中的两个值的总数？
【发布时间】：2016-10-27 14:05:30
【问题描述】：

我在 WPF 应用程序中有两个 ListBoxes，其中包含学校课程和费用。但是，在运行时，我应该显示两个值的总和的标签只显示最近选择的值。我怎样才能使总计实际计算两个选定的值？

XAML：

<Grid>
    <ListBox x:Name="courseListBox" SelectionChanged="courseListBox_SelectionChanged" HorizontalAlignment="Left" Height="126" VerticalAlignment="Top" Width="120" Margin="42,35,0,0">
        <ListBoxItem>Intro to Comp Sci</ListBoxItem>
        <ListBoxItem>Honors Comp Sci</ListBoxItem>
        <ListBoxItem>AP Comp Sci A</ListBoxItem>
        <ListBoxItem>AP Comp Sci P</ListBoxItem>
        <ListBoxItem>Independent Study</ListBoxItem>
        <ListBoxItem>Webpage Design</ListBoxItem>
    </ListBox>

    <ListBox x:Name="classListBox" SelectionChanged="classListBox_SelectionChanged" HorizontalAlignment="Left" Height="85" Margin="42,197,0,0" VerticalAlignment="Top" Width="120">
        <ListBoxItem>Freshman</ListBoxItem>
        <ListBoxItem>Sophomore</ListBoxItem>
        <ListBoxItem>Junior</ListBoxItem>
        <ListBoxItem>Senior</ListBoxItem>
    </ListBox>
    <Label x:Name="totalLabel" Content="25" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="168,34,0,0"/>
    <Border BorderBrush="Black" BorderThickness="1" HorizontalAlignment="Left" Height="28" VerticalAlignment="Top" Width="120" Margin="42,9,0,0"/>
    <Border BorderBrush="Black" BorderThickness="1" HorizontalAlignment="Left" Height="28" VerticalAlignment="Top" Width="120" Margin="42,169,0,0"/>

</Grid>

C#：

public partial class MainWindow : Window
{
    public int courseFee = 0;
    public int classFee = 0;
    public int totalCost = 0;
    public MainWindow()
    {
        InitializeComponent();
    }
    private void courseListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        int selected = courseListBox.SelectedIndex;
        if (selected == 0)
            classFee = 545;
        if (selected == 1)
            classFee = 615;
        if (selected == 2)
            classFee = 1500;
        if (selected == 3)
            classFee = 1000;
        if (selected == 4)
            classFee = 2500;
        if (selected == 5)
            classFee = 1720;
        totalCost = courseFee + classFee;
        totalLabel.Content = totalCost;
    }

    private void classListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        int selected = classListBox.SelectedIndex;
        if (selected == 0)
            classFee = 350;
        if (selected == 1)
            classFee = 275;
        if (selected == 2)
            classFee = 200;
        if (selected == 3)
            classFee = 150;
        totalCost = courseFee + classFee;
        totalLabel.Content = totalCost;
    }
}

【问题讨论】：

将 courseListBox_SelectionChanged 中的“classFee”更改为“courseFee”

标签： c# wpf xaml listbox

【解决方案1】：

服务器是无状态的，因此您无法记住回发之间的费用值。只需将这两个过程结合起来即可。

protected void getTotal() 
    {
        int selected = courseListBox.SelectedIndex;
        if (selected == 0)
            classFee = 545;
        if (selected == 1)
            classFee = 615;
        if (selected == 2)
            classFee = 1500;
        if (selected == 3)
            classFee = 1000;
        if (selected == 4)
            classFee = 2500;
        if (selected == 5)
            classFee = 1720;
        int total = classFee;
        selected = classListBox.SelectedIndex;
        if (selected == 0)
            classFee = 350;
        if (selected == 1)
            classFee = 275;
        if (selected == 2)
            classFee = 200;
        if (selected == 3)
            classFee = 150;
        total += classFee;
        totalLabel.Content = total;
    }

    private void classListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
       getTotal();
    }

（使两个列表框使用相同的事件处理程序）

【讨论】：

这是一个 WPF 应用程序。 server 是什么意思？

【解决方案2】：

首先将 courseListBox_SelectionChanged 方法中的 classFee 更改为 courseFree 可能是个好主意

代码可能是这样的......

int value = 0;
            for (int i = 0; i < listView1.Items.Count; i++)
            {
                value += int.Parse(listView1.Items[i].SubItems[e.Column].Text);
            }

            textBox1.Text = value.ToString();

【讨论】：

【解决方案3】：

我认为您的意思是课程费用，而不是 courseListBox_SelectionChanged 中的课程费用

private void courseListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        int selected = courseListBox.SelectedIndex;
        if (selected == 0)
            courseFee = 545;
        if (selected == 1)
            courseFee = 615;
        if (selected == 2)
            courseFee = 1500;
        if (selected == 3)
            courseFee = 1000;
        if (selected == 4)
            courseFee = 2500;
        if (selected == 5)
            courseFee = 1720;
        totalCost = courseFee + classFee;
        totalLabel.Content = totalCost;
    }

【讨论】：