wpf c＃在一个窗口中放入一个来自另一个窗口的值

Question

我在WPF C＃智能城市有一个gui 我有2个Window Forms.In第一个我有一个组合框。在第二个我有一个标签。我在第一个按钮保存我选择的组合框值并进入第二个窗口。

button_click上的代码是：

ComboBoxItem typeItem_a = (ComboBoxItem)comboBox_a.SelectedItem;
string destination_a = typeItem_a.Content.ToString();       
Window1 SmartPlan2 = new Window1();
this.Hide();
SmartPlan2.ShowDialog(); // change window

现在我想在第二个窗口中自动将我保存的字符串（字符串destination_a）设置为标签。任何想法？

Answer 1

@Ragavan是对的，你真的想尝试用MVVM做，这里有一个例子说明你想做什么：

Window1.xaml

<Window x:Class="double_windiwed_mvvm.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:double_windiwed_mvvm"
    mc:Ignorable="d"
    Title="Window1" Height="300" Width="300">
<Grid>
    <ComboBox ItemsSource="{Binding Items}" SelectedItem="{Binding SelectedItem, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
              HorizontalAlignment="Left" VerticalAlignment="Top" Width="120" Margin="10">
        <ComboBox.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding Name}" />
            </DataTemplate>
        </ComboBox.ItemTemplate>
    </ComboBox>

</Grid>

Window2.xaml

<Window x:Class="double_windiwed_mvvm.Window2"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:double_windiwed_mvvm"
    mc:Ignorable="d"
    Title="Window2" Height="300" Width="300">
<Grid>
    <Label Content="{Binding SelectedItem.Name}"
           HorizontalAlignment="Left" VerticalAlignment="Top" Width="120" Margin="10"/>
</Grid>

ViewModel.cs

class ViewModel : INotifyPropertyChanged
{
    public ObservableCollection<Person> Items { get; set; } = new ObservableCollection<Person>();

    private Person _selectedItem;
    public Person SelectedItem
    {
        get { return _selectedItem; }
        set
        {
            if(_selectedItem != null && _selectedItem.Equals(value)) { return; }
            _selectedItem = value;
            PropertyChanged(this, new PropertyChangedEventArgs("SelectedItem"));
        }
    }

    // INotifyPropertyChanged emplementation
    public event PropertyChangedEventHandler PropertyChanged;
}

Person.cs

class Person
{
    public string Name { get; set; }
}

您的入口点

ViewModel vm = new ViewModel();
vm.Items.Add(new Person { Name = "Bob" });
vm.Items.Add(new Person { Name = "Marie" });
vm.Items.Add(new Person { Name = "John" });

Window1 w1 = new Window1();
w1.DataContext = vm;

Window2 w2 = new Window2();
w2.DataContext = vm;

w1.Show();
w2.Show();

您可以使用窗口的DataContext指定要使用的ViewModel，如果同时为两者提供相同的ViewModel，它们将自动更新彼此。
我强烈建议你看一下MVVM＆amp; amp;绑定适用于WPF。