更改组合框WPF的值时触发ComoBox SelectionChanged事件 [英] ComoBox SelectionChanged event firing when we changing value of combobox WPF

问题描述

为什么使用ComoboBox?当我们更改组合框的值时，会触发SelectionChanged事件在WPF中?

why ComoboBox  SelectionChanged event firing when we changed value of combobox  in WPF?

     <ComboBox  Name="onClockComboBox"  Grid.Row="5" Grid.Column="0" Grid.ColumnSpan="2" Width="200" Height="30" StaysOpenOnEdit="True" IsSynchronizedWithCurrentItem="True" OpenDropDownOnFocus="True" 
                                    ItemsSource="{Binding TravelOtherModel.OnClockOptionListCollection,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Center"  
                                    DisplayMemberPath="OptionName" SelectedValuePath="RowNo" IsFilteringEnabled="True" IsEditable="True" Margin="80,3,0,0">
                                    <ie:Interaction.Triggers>
                                            <ie:EventTrigger EventName="SelectionChanged">
                                            <ie:InvokeCommandAction Command="{Binding OnClockComboBoxSelectedItemChangedCommand}" CommandParameter="{Binding ElementName=onClockComboBox}" >
                                                </ie:InvokeCommandAction>
                                            </ie:EventTrigger>
                                        </ie:Interaction.Triggers>
                                    </RadComboBox>

和

SelectionChanged Event Code is -

     public void OnClockComboBoxSelectedItemChangedCommand_Event(object obj)
        {
            try
            {
                ComboBox onClockComboBox = obj as ComboBox;
                var item = onClockComboBox.SelectedItem as OnClockOption; 
                string s= onClockComboBox.SelectedValue.ToString();
                onClockComboBox.SelectedValue = "0";
            }
            catch (Exception ex)
            {
                
            }
        }

当我们通过下面的代码设置默认的选择"值时，它再次触发选择已更改"事件的原因是什么?

When we set default 'select' value by below code then its again firing selection Changed event why?

 onClockComboBox.SelectedValue = "0";

推荐答案

当ComboBox中的选择更改时，应该引发SelectionChanged事件: https://msdn.microsoft.com/zh-CN/library/system.windows.controls.primitives.selector.selectionchanged(v=vs.110).aspx

The SelectionChanged event is supposed to be raised when the selection in the ComboBox changes: https://msdn.microsoft.com/en-us/library/system.windows.controls.primitives.selector.selectionchanged(v=vs.110).aspx

但是，请不要在这些论坛中询问有关第三方控件的问题，因为它们仅适用于Microsoft的产品和技术.如果您对Telerik的RadComboBox控件或其任何其他控件有任何疑问或问题，则您 应该在自己的支持论坛中开始新话题: http://www.telerik.com/forums/wpf/combobox .

But please don't ask questions about third-party controls in these forums as they are intended for Microsoft's products and technologies only. If you have any questions or issues regarding Telerik's RadComboBox control or any other of their controls, you should start a new thread in their own support forums: http://www.telerik.com/forums/wpf/combobox.

希望有帮助.

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