RKIS/Task1/View/TaskWindow.xaml

<Window x:Class="Task1.TaskWindow"
        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:Task1"
        mc:Ignorable="d"
        Title="Задачи" Height="400" Width="800" MinHeight="400" MinWidth="800" MaxHeight="500" MaxWidth="1000" Background="#FFD3E8F9">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="52*"/>
            <RowDefinition Height="43*"/>
            <RowDefinition Height="51*"/>
            <RowDefinition Height="62*"/>
            <RowDefinition Height="105*"/>
            <RowDefinition Height="70*"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="143*"/>
            <ColumnDefinition Width="173*"/>
            <ColumnDefinition Width="168*"/>
            <ColumnDefinition Width="142*"/>
            <ColumnDefinition Width="93*"/>
            <ColumnDefinition Width="80*"/>
        </Grid.ColumnDefinitions>
        <DataGrid Grid.ColumnSpan="6" x:Name="Tasks_grid" ItemsSource="{Binding Tasks}" SelectedItem="{Binding Task}" AutoGenerateColumns="False" IsReadOnly="True" ScrollViewer.CanContentScroll="True" ColumnWidth="*" Margin="10,10,0,70" Grid.RowSpan="5" Grid.Row="1" HorizontalAlignment="Left" Width="767" SelectionChanged="Tasks_grid_SelectionChanged">
            <DataGrid.Columns>
                <DataGridTextColumn Header="Id" Binding="{Binding TaskId}"/>
                <DataGridTextColumn Header="Название" Binding="{Binding Name}"/>
                <DataGridTextColumn Header="Дата" Binding="{Binding Date, StringFormat={}{0:yyyy}}"/>
                <DataGridTextColumn Header="Статус" Binding="{Binding StatusTask1.Name}"/>
                <DataGridTextColumn Header="Описание" Binding="{Binding Description}"/>
                <DataGridTextColumn Header="Логин принявщего" Binding="{Binding UserAcceptedTask.Login}"/>
                <DataGridTextColumn Header="Логин создателя" Binding="{Binding UserCreatedTask.Login}"/>
            </DataGrid.Columns>
        </DataGrid>
        <Label Content="Поиск по логину: " FontSize="15" HorizontalAlignment="Left" VerticalAlignment="Center" Height="30" Width="138" Grid.Row="5"/>
        <TextBox Grid.Row="5" VerticalAlignment="Top" Margin="9,29,13,0" Text="{Binding LoginUser}"  Grid.Column="1" />
        <Button Content="Поиск" Grid.Column="2" Command="{Binding Poisk}" CommandParameter="{Binding ElementName=Tasks_grid, Path = SelectedItem}" FontSize="15" Width="91" Grid.Row="5" Height="27" VerticalAlignment="Top" HorizontalAlignment="Left"  Margin="8,25,0,0"/>
        <Button Content="Назад" Grid.Column="4" Command="{Binding Nazad}" CommandParameter="{Binding ElementName=Tasks_grid, Path = SelectedItem}" FontSize="15" Width="91" Height="27" VerticalAlignment="Top" HorizontalAlignment="Left"  Margin="42,16,0,0" Grid.ColumnSpan="2"/>
        <Button Content="Взять задачу" Command="{Binding Prinat}" CommandParameter="{Binding ElementName=Tasks_grid, Path = SelectedItem}" FontSize="15" Width="126" Height="34" VerticalAlignment="Center" HorizontalAlignment="Center" Click="Button_Click"/>
        <Button Content="Выполненые задачи" Command="{Binding End}" CommandParameter="{Binding ElementName=Tasks_grid, Path = SelectedItem}" FontSize="15" Height="34" VerticalAlignment="Center"  Margin="9,0,10,0" RenderTransformOrigin="0.656,0.574" Grid.Column="1"/>
        <Button Content="Доступные задачи" Grid.Column="2" Command="{Binding Dostup}"  CommandParameter="{Binding ElementName=Tasks_grid, Path = SelectedItem}" FontSize="15" Width="153" Height="34" VerticalAlignment="Center" HorizontalAlignment="Center"/>
        <Button Content="Сменить статус" Command="{Binding Change}" CommandParameter="{Binding ElementName=Tasks_grid, Path = SelectedItem}" Grid.Column="3" FontSize="15" Width="124" HorizontalAlignment="Left"  Margin="10,10,0,4" RenderTransformOrigin="0.492,0.629"/>
        <Button Content="Начальная стр." Command="{Binding Update}"  CommandParameter="{Binding ElementName=Tasks_grid, Path = SelectedItem}" FontSize="15" Width="143" Height="34" VerticalAlignment="Center" HorizontalAlignment="Left" RenderTransformOrigin="-1,2.147" Grid.Column="3" Grid.Row="5" Grid.ColumnSpan="2" Margin="71,0,0,0"/>
    </Grid>
</Window>