具有静态值的 WPF 组合框

Question

我需要为我的 WPF 应用程序分配一些静态组合框。我正在做如下。 我收到错误内容无法识别？在获得 selectedIndex 和 value 的位置并相应地设置它们时，我如何才能最好地静态分配它们？

<ComboBox Name="month" >
    <ComboBoxItem Tag="January" content="01" />
    <ComboBoxItem Tag="February" content="02" />
</ComboBox>

Answer 1

您的ComboBox 的正文中有ComboBoxItem。因此，所选值必须首先类型转换为 ComboBoxItem。然后当它被转换时，你可以通过 .value 属性获取值。请参阅下面的代码。

在 XAML 中

<ComboBox x:Name="month">
   <ComboBoxItem Content="January"/>
   <ComboBoxItem Content="February"/>
   ...
</ComboBox>

在 C# 中

ComboBoxItem selectedItem = (ComboBoxItem)month.SelectedValue;
int index = month.SelectedIndex; //To get selected Index
int monthNumber = index + 1;
string itemvalue = selectedItem.Content;

您不需要Tag 属性。

Answer 2

在用户向下滚动时添加无限年份 使用此代码，每当看到组合框的最后一年时，接下来的 10 年将被添加到组合框并显示给用户。我希望这是你想要的。 RequestBringIntoView 事件在 XAML 组件进入视图时触发，即当它对用户可见时

   public MainWindow()
    {
        InitializeComponent();
        PopulateNextTenYears();
    }



    private void PopulateNextTenYears()
    {
        //Check to see whether the year_combo is empty.
        //If yes, then simply add years from today to next 10 years
        if(year_combo.Items.Count==0)
        {
          for(int i=0;i<10;i++)
          {
              ComboBoxItem itemCombo = new ComboBoxItem()
              {
                  Content=""+(DateTime.Now.Year+i)
              };

              if(i==9)
              {
                  //If the combobox item is last, then register it to RequestBringIntoView event handler
                  itemCombo.RequestBringIntoView += itemCombo_RequestBringIntoView;
              }
              //Add the combobox item to year_combo
              year_combo.Items.Add(itemCombo);
          }
        }
            //If year_combo has some items i.e it is not empty, then extract the last year from combobox
            //using this year, add 10 more years
        else
        {
            ComboBoxItem itemCombo = (ComboBoxItem)year_combo.Items[year_combo.Items.Count - 1];
            int nextYear = Convert.ToInt32(itemCombo.Content)+1;
            for(int i=0;i<10;i++)
            {
                 itemCombo = new ComboBoxItem()
                {
                    Content = "" + (nextYear + i)
                };

                if (i == 9)
                {
                    //Again if the last item is added, then register it to RequestBringIntoView event
                    itemCombo.RequestBringIntoView += itemCombo_RequestBringIntoView;
                }
                year_combo.Items.Add(itemCombo);
            }
        }
    }

    void itemCombo_RequestBringIntoView(object sender, RequestBringIntoViewEventArgs e)
    {
        //Omce an event has been raised by a particular last combobox item, it is important to
        //unregister its RequestBringIntoView event
        ComboBoxItem itemCombo = (ComboBoxItem)sender;
        itemCombo.RequestBringIntoView -= itemCombo_RequestBringIntoView;
        //Populate next 10 years
        PopulateNextTenYears();
    }