WPF中的双向绑定 [英] TwoWay binding in WPF

问题描述

嗨


我在使用WPF中的twoway绑定时遇到问题。我有

Hi
I have a problem with getting twoway binding to work in WPF. I have

public List<AirlineMaintenanceMVVM> Maintenances { get; set; }

其中AirlineMaintenanceMVVM是：

where AirlineMaintenanceMVVM is:

public class AirlineMaintenanceMVVM
{
    private MaintenanceCenterMVVM _selectedtype;
    public AirlinerMaintenanceType Type { get; set; }

    public MaintenanceCenterMVVM SelectedType
    {
        get
        {
            return this._selectedtype;
        }
        set
        {
            this._selectedtype = value;
            this.NotifyPropertyChanged("SelectedType");
        }
    }

    public ObservableCollection<MaintenanceCenterMVVM> Centers { get; set; }
    public AirlineMaintenanceMVVM(AirlinerMaintenanceType type, MaintenanceCenterMVVM selected, List<MaintenanceCenterMVVM> centers)
    {
        this.Type = type;
        this.Centers = new ObservableCollection<MaintenanceCenterMVVM>();

        centers.ForEach(c => this.Centers.Add(c));

        this.SelectedType = selected;
    }
    #region Public Events

    public event PropertyChangedEventHandler PropertyChanged;

    #endregion
    #region Methods

    private void NotifyPropertyChanged(String propertyName)
    {
        PropertyChangedEventHandler handler = this.PropertyChanged;
        if (null != handler)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    #endregion
}

在xaml中我创建了一个带有ComboBox的ListBox，其中组合框绑定元素和MVVM文件中的选定值。但是，当我创建MVVM对象时设置所选值时，在显示组合框时未设置该值：

In the xaml I have created a ListBox with a ComboBox inside, where the combo box binds to the elements and selected value from the MVVM-file. But eventhough I set the selected value when I create the MVVM-object, the value is not set when the combo box is shown:

 <ListBox ItemsSource="{Binding Maintenances}" removed="Transparent" BorderThickness="0" ItemContainerStyleSelector="{StaticResource ListBoxItemStyleSelector}" VerticalAlignment="Bottom">
   <ListBox.ItemTemplate>
      <DataTemplate>
         <WrapPanel>
            <TextBlock Text="{Binding Type.Name}" VerticalAlignment="Bottom" FontWeight="Bold" Width="100">
            </TextBlock>
            <ComboBox ItemsSource="{Binding Centers,Mode=OneTime}" Width="250"

               Style="{StaticResource ComboBoxTransparentStyle}"

               SelectedItem="{Binding SelectedType,Mode=TwoWay}"

               DisplayMemberPath="Name" SelectedValuePath="Name" />
         </WrapPanel>
      </DataTemplate>
   </ListBox.ItemTemplate>
</ListBox>

从非解决方案复制的其他信息

更改组合框时，mvvm对象中的选定值文件已正确更新

additional information copied from non-solution below
The selected value files in the mvvm object is correctly updated when I change the combobox

推荐答案

嘿pjank42，



只需从ComboBox中删除SelectedValuePath =Name，即全部:-)



您正在尝试绑定Name属性（可能类型字符串）到SelectedType变量，它是MaintenanceCenterMVVM。

Hey pjank42,

just remove SelectedValuePath="Name" from the ComboBox, that's all :-)

You're trying to bind the Name Property (probably of type string) into the SelectedType variable which is a MaintenanceCenterMVVM.

这篇关于WPF中的双向绑定的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！