当项目具有相同名称时，防止ComboBox触发SelectionChanged事件吗？

Question

我有2个===，数字和颜色。

数字 ComboBoxes选项将更改颜色 ComboBox的{​​{1}}。

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问题：

如果新选择的项目与上一个项目具有相同的名称，例如“红色”，我想防止颜色 Item Source触发ComboBox事件。 ComboBox和SelectionChanged中的“红色”。

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数字组合框

此Item Source 1更改颜色 Item Source 2的{​​{1}}。

ComboBox

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列出字符串项目来源

不触发SelectionChanged事件

如果我将Item Source用于ComboBox，并且<ComboBox x:Name="cboNumbers" SelectedItem="{Binding Numbers_SelectedItem}" IsSynchronizedWithCurrentItem="True" HorizontalAlignment="Left" Margin="190,55,0,0" VerticalAlignment="Top" Width="120" SelectionChanged="cboNumbers_SelectionChanged"/> <System:String>1</System:String> <System:String>2</System:String> </ComboBox> // Change Item Source with Selection // private void cboNumbers_SelectionChanged(object sender, SelectionChangedEventArgs e) { if (vm.Numbers_SelectedItem == "1") { vm.Colors_Items = colors1; } else if (vm.Numbers_SelectedItem == "2") { vm.Colors_Items = colors2; } } 与上一个项目具有相同的名称，它将不会触发List<string> {{1} }事件。

Item Source

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列出类别项目来源（问题）

触发SelectionChanged事件

我想对SelectedItem使用此自定义ComboBox SelectionChanged，因此我可以绑定多个值，但是会触发<ComboBox x:Name="cboColors" ItemsSource="{Binding Colors_Items}" SelectedItem="{Binding Colors_SelectedItem}" IsSynchronizedWithCurrentItem="True" HorizontalAlignment="Left" Margin="190,55,0,0" VerticalAlignment="Top" Width="120" SelectionChanged="cboColors_SelectionChanged"/> // Colors Item Source 1 public List<string> colors1 = new List<string>() { "Red", //<-- same name (doesn't fire event) "Green", "Blue" }; // Colors Item Source 2 public List<string> colors2 = new List<string>() { "Red", //<-- same name (doesn't fire event) "Yellow", "Purple" }; class事件。

List<ViewModel.MyColors>

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ViewModel

Item Source

Answer 1

这是我正在使用的hack。它仍然会触发SelectionChanged Event，但是会忽略通常会在触发时运行的代码，因为我已将该代码移至绑定到SelectedItem的ViewModel String上。

组合框

public static string colors_PreviousItem;

private void cboColors_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    // Save the Previous Item
    if (!string.IsNullOrEmpty(vm.Colors_SelectedItem))
    {
        colors_PreviousItem = vm.Colors_SelectedItem;
    }

    // Select Item
    vm.Colors_SelectedItem = SelectItem(vm.Colors_Items.Select(c => c.Name).ToList(),
                                        colors_PreviousItem
                                        );

    // I used to have the code I want to run in here
}


// Select Item Method
//
public static string SelectItem(List<string> itemsName,
                                string selectedItem
                                )
{
    // Select Previous Item
    if (itemsName?.Contains(selectedItem) == true)
    {
        return selectedItem;
    }

    // Default to First Item
    else
    {
        return itemsName.FirstOrDefault();
    }
}

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ViewModel

// Selected Item
//
private string _Colors_SelectedItem { get; set; }
public string Colors_SelectedItem
{
    get { return _Colors_SelectedItem; }
    set
    {
        var previousItem = _Colors_SelectedItem;
        _Colors_SelectedItem = value;
        OnPropertyChanged("Colors_SelectedItem");

        // Ignore if Previous Item is different than New Item
        if (previousItem != value)
        {
            // Moved the code I want to run in here
            // I want to ignore the code in here when the SelectionChanged Event fires 
            // and the Previous and Newly Selected Items are the same
        }

    }
}