Styling WPF ComboBox items

Use ItemContainerStyle instead of ItemTemplate:

    <ComboBox ItemsSource="{Binding People}" Width="100" Height="20">        <ComboBox.ItemContainerStyle>            <Style TargetType="ComboBoxItem">                <Setter Property="Foreground" Value="Pink" />                <Style.Triggers>                    <DataTrigger Binding="{Binding Path=Sex}" Value="Male">                        <Setter Property="Foreground" Value="Blue" />                    </DataTrigger>                </Style.Triggers>            </Style>        </ComboBox.ItemContainerStyle>    </ComboBox>

You should use "Style" triggers instead of "TextBlock.Triggers"

use this XAML:

<Window x:Class="ComboBoxColour.MainWindow"        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"        Title="MainWindow" Height="350" Width="525">    <StackPanel Orientation="Vertical">        <ComboBox ItemsSource="{Binding People}" Width="100" Height="20">            <ComboBox.ItemTemplate>                <DataTemplate>                    <TextBlock Name="somePerson" Text="{Binding Path=Name}">                        <TextBlock.Style>                            <Style TargetType="TextBlock">                                <Style.Triggers>                                    <DataTrigger Binding="{Binding Path=Sex}" Value="Male">                                        <DataTrigger.Setters>                                            <Setter Property="Foreground" Value="blue"/>                                        </DataTrigger.Setters>                                    </DataTrigger>                                    <DataTrigger Binding="{Binding Path=Sex}" Value="Female">                                        <DataTrigger.Setters>                                            <Setter Property="Foreground" Value="Pink"/>                                        </DataTrigger.Setters>                                    </DataTrigger>                                </Style.Triggers>                            </Style>                        </TextBlock.Style>                    </TextBlock>                </DataTemplate>            </ComboBox.ItemTemplate>        </ComboBox>    </StackPanel></Window>

Now you'll have blue for male and pink for female.