WPF - 组合框 - 当用户在组合中输入文本时添加项目
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WPF - Combobox - Add Item when user enter text in combo
提问by Frederic7391
I have a ComboBoxbinded with an ObservableCollection. How can I do when user enter a text in the ComboBox, if item not in the list, the code automatically add a new item to the list?
我有一个ComboBox绑定的ObservableCollection. 当用户在 中输入文本时ComboBox，如果项目不在列表中，代码会自动将新项目添加到列表中，我该怎么办？
<ComboBox Name="cbTypePLC"
Height="22"
ItemsSource="{StaticResource TypePLCList}"
SelectedItem="{Binding TypePLC}" IsReadOnly="False" IsEditable="True">
</ComboBox>
回答by Bhupendra Joshi
Bind Text property of your combo box to your view model item and then add to the bound collection there, like,
将组合框的 Text 属性绑定到您的视图模型项，然后添加到那里的绑定集合中，例如，
Text="{Binding UserEnteredItem, UpdateSourceTrigger=LostFocus}"
Change the UpdateSourceTrigger to LostFocus because default (PropertyChanged) will communicate each character change to your viewmodel.
将 UpdateSourceTrigger 更改为 LostFocus 因为默认值 (PropertyChanged) 会将每个字符更改传达给您的视图模型。
// user entered value
private string mUserEnteredItem;
public string UserEnteredItem {
get {
return mUserEnteredItem;
}
set {
if (mUserEnteredItem != value) {
mUserEnteredItem = value;
TypePLCList.Add (mUserEnteredItem);
// maybe you want to set the selected item to user entered value
TypePLC = mUserEnteredItem;
}
}
}
// your selected item
private string mTypePLC;
public string TypePLC {
get {
return mTypePLC;
}
set {
if (mTypePLC != value) {
mTypePLC = value;
// notify change of TypePLC INPC
}
}
}
// your itemsource
public ObservableCollection <string> TypePLCList { set; private set;}
