<DataGrid Grid.Row="0" ItemsSource="{Binding ItemList2}" >
        
            <DataGrid.Resources>
                <Style TargetType="DataGridCell" x:Key="SelectedColumnStyle">
                    <Setter Property="Background" Value="Red"/>
                </Style>
            </DataGrid.Resources>

        </DataGrid>
       
        <StackPanel VerticalAlignment="Bottom">
            <RadioButton GroupName="ColorRow" Content="выделить 1 столбец" Command="{Binding MenuItem_Click_AddStringCoil}" />
            <RadioButton GroupName="ColorRow" Content="выделить 2 столбца" Command="{Binding MenuItem_Click_AddStringCoil}" />
        </StackPanel>

        DataGridColumn CurrentColumn = null;

        private DelegateCommand _MenuItem_Click_AddStringCoil;
        public ICommand MenuItem_Click_AddStringCoil { get { return _MenuItem_Click_AddStringCoil ?? (_MenuItem_Click_AddStringCoil = new DelegateCommand(DataGrid_CurrentCellChanged)); } }


        private void DataGrid_CurrentCellChanged(object sender)
        {
            
// как сказать, что, например столбец 0 и 3 закрасить

        }

]<Window x:Class="HelpProject.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:HelpProject"
        xmlns:models="clr-namespace:HelpProject.ViewModel"
        
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">

    <Grid>

        
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
       <DataGrid x:Name="myDatagrid" Grid.Row="0" ItemsSource="{Binding ItemList2}" >
        
            <DataGrid.Resources>
                <Style TargetType="DataGridCell" x:Key="SelectedColumnStyle">
                    <Setter Property="Background" Value="Red"/>
                </Style>
            </DataGrid.Resources>

        </DataGrid>