How do I compare List<string>’ items (content،name or etc), with selected items in ComboBox?

Question

First of all I am sorry for my language grammar because my first language is Persian (Iran). I have a ComboBox which has CheckBox for multi selection and multi deletion then i tried to following codes but i did not reach a conclusion.

<Style x:Key="{x:Type ComboBoxItem}" TargetType="{x:Type ComboBoxItem}">  
        <Setter Property="SnapsToDevicePixels" Value="true" />  
        <Setter Property="OverridesDefaultStyle" Value="true" />  
        <Setter Property="Template">  
            <Setter.Value>  
                <ControlTemplate TargetType="{x:Type ComboBoxItem}">  
                    <Border x:Name="Border" SnapsToDevicePixels="true" Background="Transparent">  
                        <VisualStateManager.VisualStateGroups>  
                            <VisualStateGroup x:Name="SelectionStates">  
                                <VisualState x:Name="Unselected" />  
                                <VisualState x:Name="Selected">  
                                    <Storyboard>  
                                        <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border" Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)">  
                                            <EasingColorKeyFrame KeyTime="0" Value="#FFC5CBF9" />  
                                        </ColorAnimationUsingKeyFrames>  
                                    </Storyboard>  
                                </VisualState>  
                                <VisualState x:Name="SelectedUnfocused">  
                                    <Storyboard>  
                                        <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border" Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)">  
                                            <EasingColorKeyFrame KeyTime="0" Value="#FFDDDDDD" />  
                                        </ColorAnimationUsingKeyFrames>  
                                    </Storyboard>  
                                </VisualState>  
                            </VisualStateGroup>  
                        </VisualStateManager.VisualStateGroups>  
                        <CheckBox Name="MultiSelectCheckBox" Content="{Binding}" Checked="MultiSelectCheckBox_Checked">  
                        </CheckBox>  
                    </Border>  
                </ControlTemplate>  
            </Setter.Value>  
        </Setter>  
</Style>  

Code behind:

    List<string> CheckedList = new List<string>();  
    private void MultiSelectCheckBox_Checked(object sender, RoutedEventArgs e)  
    {  
        CheckBox CB = sender as CheckBox;  
        CheckedList.Add(CB.Content.ToString());  
    }  
    private void Delete_Button_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)  
    {  
        switch (BookCategory_ComboBox.Text)  
        {  
            case null:  
                break;  
            default:  
                for (int i = 0; i < CheckedList.Count - 1; i++)  
                {  
                    string a = CheckedList[i].ToString();  
                    if (CheckedList[i].ToString()==BookCategory_ComboBox.Items[i].ToString())  
                    {  
                        BookCategory_ComboBox.Items.Remove(BookCategory_ComboBox.Items[i]);  
                    }  
                }  
                break;  
        }  
    }  

Thanks

Answer 1

Thank you, but I found a solution that is simpler and more complete.

<Style x:Key="{x:Type ComboBoxItem}" TargetType="{x:Type ComboBoxItem}">  
        <Setter Property="SnapsToDevicePixels" Value="true" />  
        <Setter Property="OverridesDefaultStyle" Value="true" />  
        <Setter Property="Template">  
            <Setter.Value>  
                <ControlTemplate TargetType="{x:Type ComboBoxItem}">  
                    <Border x:Name="Border" SnapsToDevicePixels="true" Background="Transparent">  
                        <VisualStateManager.VisualStateGroups>  
                            <VisualStateGroup x:Name="SelectionStates">  
                                <VisualState x:Name="Unselected" />  
                                <VisualState x:Name="Selected">  
                                    <Storyboard>  
                                        <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border" Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)">  
                                            <EasingColorKeyFrame KeyTime="0" Value="#FFC5CBF9" />  
                                        </ColorAnimationUsingKeyFrames>  
                                    </Storyboard>  
                                </VisualState>  
                                <VisualState x:Name="SelectedUnfocused">  
                                    <Storyboard>  
                                        <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border" Storyboard.TargetProperty="(Panel.Background).(SolidColorBrush.Color)">  
                                            <EasingColorKeyFrame KeyTime="0" Value="#FFDDDDDD" />  
                                        </ColorAnimationUsingKeyFrames>  
                                    </Storyboard>  
                                </VisualState>  
                            </VisualStateGroup>  
                        </VisualStateManager.VisualStateGroups>  
                        <CheckBox Name="MultiSelectCheckBox" Content="{Binding}" Checked="MultiSelectCheckBox_Checked" Unchecked="MultiSelectCheckBox_Unchecked">  
                        </CheckBox>  
                    </Border>  
                </ControlTemplate>  
            </Setter.Value>  
        </Setter>  
    </Style>  

Code behind

//Global List<string>  
List<string> CheckedList = new List<string>();  
    private void Add_Button_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)  
    {  
        switch (BookCategory_ComboBox.Text)  
        {  
            case null:  
                break;  
            default:  
                //In order to avoid duplication  
                if (!BookCategory_ComboBox.Items.Contains(BookCategory_ComboBox.Text.Trim().Substring(0, 1).ToUpper() + BookCategory_ComboBox.Text.Trim().Substring(1, BookCategory_ComboBox.Text.Trim().Length - 1).ToLower()))  
                {  
                 //Uppercase first letter of string  
                    BookCategory_ComboBox.Items.Add(BookCategory_ComboBox.Text.Trim().Substring(0, 1).ToUpper() + BookCategory_ComboBox.Text.Trim().Substring(1, BookCategory_ComboBox.Text.Trim().Length - 1).ToLower());  
                }  
                //Sort  
                BookCategory_ComboBox.Items.SortDescriptions.Add(new System.ComponentModel.SortDescription("", System.ComponentModel.ListSortDirection.Ascending));  

                CheckedList.Clear();  
                break;  
        }  
    }  

    private void MultiSelectCheckBox_Checked(object sender, RoutedEventArgs e)  
    {  
        CheckBox CB = sender as CheckBox;  
        CheckedList.Add(CB.Content.ToString());  
    }  
    private void MultiSelectCheckBox_Unchecked(object sender, RoutedEventArgs e)  
    {  
        CheckBox CB = sender as CheckBox;  
        CheckedList.Remove(CB.Content.ToString());  
    }  
    private void Delete_Button_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)  
    {  
        switch (BookCategory_ComboBox.Items)  
        {  
            case null:  
                break;  
            default:  
                List<string> CB_Item = new List<string>();  
                for (int i = BookCategory_ComboBox.Items.Count - 1; i >= 0; i--)  
                {  
                    if (!CheckedList.Contains(BookCategory_ComboBox.Items[i].ToString()))  
                    {  
                        CB_Item.Add(BookCategory_ComboBox.Items[i].ToString());  
                    }  
                }  
                BookCategory_ComboBox.Items.Clear();  
                for (int i = CB_Item.Count - 1; i >= 0; i--)  
                {  
                    BookCategory_ComboBox.Items.Add(CB_Item[i].ToString());  
                }  
                //Uppercase first letter of string  
                BookCategory_ComboBox.Items.SortDescriptions.Add(new System.ComponentModel.SortDescription("", System.ComponentModel.ListSortDirection.Ascending));  
                BookCategory_ComboBox.Items.Refresh();  
                break;  
        }  
    }  

100% works.

Answer 2

Did you want delete the selected items in ComboBox which named BookCategory_ComboBox by clicking the Button which named Delete_Button? I made a demo to implement it as below, if I misunderstand your quesion, please point out.

  public partial class MainWindow : Window  
    {  
        ObservableCollection<City> oldlist = new ObservableCollection<City>();  
        ObservableCollection<City> newlist = new ObservableCollection<City>();  
        ViewModel vm = new ViewModel();  
  
        public MainWindow()  
        {  
            InitializeComponent();  
            oldlist = vm.list;  
            BookCategory_ComboBox.ItemsSource = oldlist;  
              
        }  
  
        ObservableCollection<string> CheckedList = new ObservableCollection<string>();  
        private void MultiSelectCheckBox_Checked(object sender, RoutedEventArgs e)  
        {  
            CheckBox CB = sender as CheckBox;  
            CheckedList.Add(CB.Content.ToString());  
            //MessageBox.Show(CB.Content.ToString());  
        }  
        private void Delete_Button_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)  
        {  
            switch (BookCategory_ComboBox.Text)  
            {  
                case null:  
                    break;  
                default:  
                    for (int i = 0; i < CheckedList.Count; i++)  
                    {  
                        string a = CheckedList[i].ToString();  
                        newlist = (new ViewModel()).list;  
                        foreach (City item in oldlist)  
                        {  
                            if (a == item.Name.ToString())  
                            {  
                                newlist.Remove(newlist.Where(o=>o.Name==a).FirstOrDefault());  
                            }  
                        }  
                        BookCategory_ComboBox.ItemsSource = newlist;  
                        BookCategory_ComboBox.Items.Refresh();  
  
                    }  
                    break;  
            }  
        }  
  
         
    }  
  
    public class ViewModel  
    {  
  
        public ViewModel()  
        {  
            list.Add(new City { ID = 1, Name = "City1" });  
            list.Add(new City { ID = 2, Name = "City2" });  
            list.Add(new City { ID = 3, Name = "City3" });  
        }  
  
       public ObservableCollection<City> list { get; set; } = new ObservableCollection<City>();  
        
    }  
  
    public class City  
    {  
        public int ID { get; set; }  
        public string Name { get; set; }  
  
        public override string ToString()  
        {  
            return $"{ Name}";  
        }  
    }  

The result picture:

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