Conditional List itemtemplate or datatemplate in WPF

Just specifying DataTemplates in the Resources with the respective DataType is enough, e.g.

<ListView ItemsSource="{Binding Data}">
    <ListView.Resources>
        <!-- Do NOT set the x:Key -->
        <DataTemplate DataType="{x:Type local:Employee}">
            <TextBlock Text="{Binding Name}" Foreground="Blue"/>
        </DataTemplate>
        <DataTemplate DataType="{x:Type local:Machine}">
            <TextBlock Text="{Binding Model}" Foreground="Red"/>
        </DataTemplate>
    </ListView.Resources>
</ListView>

(Note that DataTemplate.DataType can also be used for implicit XML data templating (see docs), the property type for that reason is not System.Type, so unlike in Style.TargetType you have to use x:Type to reference a CLR-type. If you just enter a string it will not be converted to a type.)

You might also want to look into CompositeCollections, to get clean merged lists of varying types.

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Sample data i used:

ObservableCollection<Employee> data = new ObservableCollection<Employee>(new Employee[]
{
    new Employee("Hans", "Programmer")      ,
    new Employee("Elister", "Programmer")   ,
    new Employee("Steve", "GUI Designer")   ,
    new Employee("Stephen", "GUI Designer") ,
    new Employee("Joe", "Coffee Getter")    ,
    new Employee("Julien", "Programmer")    ,
    new Employee("John", "Coffee Getter")   ,
});
ObservableCollection<Machine> data2 = new ObservableCollection<Machine>(new Machine[]
{
    new Machine("XI2",    String.Empty),
    new Machine("MK2-xx", String.Empty),
    new Machine("A2-B16", String.Empty),
});
CompositeCollection cc1 = new CompositeCollection();
cc1.Add(new CollectionContainer() { Collection = data });
cc1.Add(new CollectionContainer() { Collection = data2 });
Data = cc1;