ESOFT_LR/ROGOZ/Pages/AddTask.xaml

<Page x:Class="ROGOZ.Pages.AddTask"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
      xmlns:local="clr-namespace:ROGOZ.Pages"
      mc:Ignorable="d" 
      d:Height="620" d:Width="750"
      Title="AddTask">

    <Grid>

        <StackPanel HorizontalAlignment="Center" Height="600" Width="750">
            <Label Style="{StaticResource LabelStyle}" HorizontalAlignment="Center">
                Добавление задачи
            </Label>
            <StackPanel Orientation="Vertical" HorizontalAlignment="Center" Height="370" Width="750" Margin="0,20,0,0">
                <StackPanel Orientation="Horizontal" Width="750" Margin="0,15,0,0">
                    <TextBlock Text="Задача:" Style="{StaticResource BlockHeader}" HorizontalAlignment="Left" FontSize="35"/>
                    <TextBox x:Name="TaskName" Width="450" Height="35" Margin="135,0,0,0" Style="{StaticResource TextBoxStyle}"/>
                </StackPanel>

                <Separator Background="{x:Null}" Height="15"/>

                <StackPanel Orientation="Horizontal" Width="750" Margin="0,15,0,0">
                    <TextBlock Text="Статус:" Style="{StaticResource BlockHeader}" HorizontalAlignment="Left" FontSize="35"/>
                    <ComboBox x:Name="StatusBox" Width="450" Height="35" Margin="142,0,0,0" SelectedItem="{Binding Status}"/>
                </StackPanel>
                <Separator Background="{x:Null}" Height="15"/>

                <StackPanel Orientation="Horizontal" Width="750" Margin="0,15,0,0">
                    <TextBlock Text="Исполнитель:" Style="{StaticResource BlockHeader}" HorizontalAlignment="Left" FontSize="35"/>
                    <ComboBox x:Name="ExecutorBox" Width="450" Height="35" Margin="25,0,0,0" SelectedItem="{Binding Executor.User.MiddleName}"/>
                </StackPanel>
                <Separator Background="{x:Null}" Height="15"/>

                <StackPanel Orientation="Horizontal" Width="750" Margin="0,15,0,0">
                    <TextBlock Text="Менеджер:" Style="{StaticResource BlockHeader}" HorizontalAlignment="Left" FontSize="35"/>
                    <ComboBox x:Name="ManagerBox" Width="450" Height="35" Margin="83,0,0,0" SelectedItem="{Binding Manager.User.MiddleName}"/>
                </StackPanel>
            </StackPanel>
            <StackPanel Width="700" Height="70" Orientation="Horizontal" Margin="0,20">

                <Button Content="Отмена" Style="{StaticResource AuthoButtons}" Click="Button_Click"/>
                <Button Content="Сохранить" Style="{StaticResource AuthoButtons}" Margin="100,0,0,0"/>

            </StackPanel>
        </StackPanel>
    </Grid>
</Page>