英文:
How to add selectionchanged/dropdownopened to combobox via ICommand/EventTrigger in MVVP WPF
问题
我正在使用MVVM模式构建一个程序。我可以在xaml.cs文件中的非MVVM方式处理selectionchanged事件的方法。但是我不知道在MVVM中如何做到这一点。
目前，我的所有ICommand属性都在viewmodel.cs文件中，视图代码如下：
<StackPanel Grid.Row="0" Orientation="Horizontal" Margin="10,0" HorizontalAlignment="Right">
<Label Content="Ports" Margin="2" />
<ComboBox IsReadOnly="True" AllowDrop="True" x:Name="ComboBox_SerialPort" MinWidth="60" Margin="5"
ItemsSource="{Binding SerialPortList}" SelectedValue="{Binding SelectedSerialPort}"
SelectionChanged="{Binding Cmd_ComboBox_SerialDropDownSelectionChanged}">
</ComboBox>
</StackPanel>
显然，直接将ICommand属性绑定到SelectionChanged不起作用。但是ComboBox控件中没有Command属性。那么，我如何将ICommand附加到控件事件中呢？
谢谢
英文:
I'm building a program with MVVM pattern
I can handle selectionchanged event with method in xaml.cs file in non-MVVM way. but don't know how to do this in MVVM.
Currently all my ICommand properties are in viewmodel.cs file, and view code like below
<StackPanel Grid.Row="0" Orientation="Horizontal" Margin="10,0" HorizontalAlignment="Right">
<Label Content="Ports" Margin="2" />
<ComboBox IsReadOnly="True" AllowDrop="True" x:Name="ComboBox_SerialPort" MinWidth="60" Margin="5"
ItemsSource="{Binding SerialPortList}" SelectedValue="{Binding SelectedSerialPort}"
SelectionChanged="{Binding Cmd_ComboBox_SerialDropDownSelectionChanged}" >
</ComboBox>
</StackPanel>
Apparently directly binding ICommand property to SelectionChanged is not working. but there's no Command property in Combobox control. So how do I attach ICommand to control events
Thanks
答案1
得分: 1
你可以在 SelectedSerialPort 源属性的 setter 中处理你的选择更改逻辑，该属性会在你在 ComboBox 中选择一个值时被设置。
英文:
You could handle your selection changed logic in the setter of the SelectedSerialPort source property which will get set when you select a value in the ComboBox.
答案2
得分: 0
Option 1:
<ComboBox>
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<i:InvokeCommandAction Command="{Binding YourCommandName}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</ComboBox>
Option 2:
<ComboBox SelectedValue="{Binding SelectedSerialPort, UpdateSourceTrigger=PropertyChanged}"/>
英文:
Option 1:
<ComboBox>
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<i:InvokeCommandAction Command="{Binding YourCommandName}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</Combobox>
Option 2:
<ComboBox SelectedValue="{Binding SelectedSerialPort, UpdateSourceTrigger=PropertyChanged}"/>
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