<Window x:Class="MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:MyWpfApp"
        mc:Ignorable="d"
        Height="auto" Width="auto" WindowState="Maximized">

    <Window.Resources>
        <DataTemplate x:Key="dtStartView"  DataType="{x:Type local:InputTabViewModel}">
            <local:InputTabView />
        </DataTemplate>

        <DataTemplate x:Key="dtSecondView" DataType="{x:Type local:CalendarControlViewModel}">
            <local:CalendarControlView />
        </DataTemplate>

        <local:WindowDataTemplateSelector x:Key="sel"
          FirstDataTemplate="{StaticResource dtStartView}" 
          SecondDataTemplate="{StaticResource dtSecondView}" />
     
    </Window.Resources>
    <Window.DataContext >
        <local:MainViewModel/>
    </Window.DataContext>
    <ContentControl  ContentTemplateSelector="{StaticResource sel}"/>
    <!--<ContentControl  Content="{Binding Path=CurrentControl}"/>-->
</Window>

using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
public class WindowDataTemplateSelector : DataTemplateSelector
{

	private string newPropertyValue;

	private DataTemplate _FirstDataTemplate;
	public DataTemplate FirstDataTemplate {
		get { return _FirstDataTemplate; }
		set { _FirstDataTemplate = value; }
	}

	private DataTemplate _SecondDataTemplate;
	public DataTemplate SecondDataTemplate {
		get { return _SecondDataTemplate; }
		set { _SecondDataTemplate = value; }
	}

	public override DataTemplate SelectTemplate(object item, DependencyObject container)
	{
		// Return MyBase.SelectTemplate(item, container)
		return FirstDataTemplate;

	}

}

        <DataTemplate x:Key="dtStartView"  DataType="{x:Type local:InputTabViewModel}">
            <local:InputTabView />
        </DataTemplate>