wpf 在运行时向 ComboBox 添加项目？
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Add items to ComboBox at runtime?
提问by herohuyongtao
I am trying to add items to a ComboBox(say Name="labelComboBox") at runtime when I pressed an add button (say with Name="add2labels" Click="add2labels_Click"). But the ComboBoxcannot show the values I newly added. What did I miss?
当我按下添加按钮（例如 with ）时，我试图在运行时向 a ComboBox（例如Name="labelComboBox"）添加项目Name="add2labels" Click="add2labels_Click"。但是ComboBox无法显示我新添加的值。我错过了什么？
The following is the event handler for the add button:
以下是添加按钮的事件处理程序：
private List<String> labels = new List<String>();
... ...
private void add2labels_Click(object sender, RoutedEventArgs e)
{
labels.Add("new value");
labelComboBox.ItemsSource = labels;
}
P.S. I am pretty sure the values were added to List<String> labelscorrectly (its count did increase each time).
PS我很确定这些值被List<String> labels正确添加（它的计数每次都增加）。
Updated with workable solutions (3 ways) :
更新了可行的解决方案（3 种方式）：
Use
ObservableCollection(@AnatoliyNikolaev's answer).Change
List<String> labelstoObservableCollection<String> labels. And only need to calllabelComboBox.ItemsSource = labels;once in all.Use
Binding(@HarshanaNarangoda's answer).Add
ItemsSource="{Binding Path=labels}"toComboBox's properties.Use
Refresh()(@EliranPe'er's anwer).Change the event handler to:
... ... labelComboBox.ItemsSource = labels; labelComboBox.Items.Refresh(); // new added
使用
ObservableCollection（@AnatoliyNikolaev 的回答）。更改
List<String> labels为ObservableCollection<String> labels。并且只需要调用labelComboBox.ItemsSource = labels;一次。使用
Binding（@HarshanaNarangoda 的回答）。添加
ItemsSource="{Binding Path=labels}"到ComboBox的属性。使用
Refresh()（@EliranPe'er 的回答）。将事件处理程序更改为：
... ... labelComboBox.ItemsSource = labels; labelComboBox.Items.Refresh(); // new added
采纳答案by Anatoliy Nikolaev
You should use ObservableCollection<T>instead of List<String>:
你应该使用ObservableCollection<T>而不是List<String>：
ObservableCollection represents a dynamicdata collection that
provides notificationswhen items get added, removed, or when the whole list is refreshed.
ObservableCollection 表示一个动态数据集合，
provides notifications当添加、删除项目或刷新整个列表时。
回答by Aftab Ahmed
Combobox has a display and value member to add values to combo-box you need to specify both.
Combobox 有一个 display 和 value 成员，可以将值添加到需要同时指定的组合框。
try this
尝试这个
ComboboxItem item = new ComboboxItem();
item.Text = "new value";
item.Value = 12;
labels.Items.Add(item);
回答by Harshana Narangoda
I think You have to change some code in XAML to following.You have to bind data to your Combo Box.
我认为您必须将 XAML 中的一些代码更改为以下代码。您必须将数据绑定到您的组合框。
<ComboBox ItemsSource="{Binding}" Height="23" HorizontalAlignment="Left" Name="comboBox1" />
回答by Eliran Pe'er
Try using labelComboBox.Items.Refresh();
尝试使用 labelComboBox.Items.Refresh();
