C#-Code

using System.Collections.ObjectModel;
using System.Linq;
using System.Windows;
using OpenFileDialog = System.Windows.Forms.OpenFileDialog;
using SaveFileDialog = System.Windows.Forms.SaveFileDialog;

namespace WpfCSVImportExport
{
    /// <summary>
    /// Interaktionslogik für MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        ObservableCollection<Mitarbeiter> mitarbeiter;
        public MainWindow()
        {
            InitializeComponent();
            mitarbeiter = new ObservableCollection<Mitarbeiter>();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {

            System.Windows.Data.CollectionViewSource mitarbeiterViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("mitarbeiterViewSource")));
            // Laden Sie Daten durch Festlegen der CollectionViewSource.Source-Eigenschaft:
            mitarbeiterViewSource.Source = mitarbeiter;//[generische Datenquelle]
        }

        private void buttonImportFilename_Click(object sender, RoutedEventArgs e)
        {
            char seperator;
            if (radioButtonImportSeperatorKomma.IsChecked == true)
            {
                seperator = ',';
            }
            else if (radioButtonImportSeperatorSemikolon.IsChecked == true)
            {
                seperator = ';';
            }
            else if (radioButtonImportSeperatorTab.IsChecked == true)
            {
                seperator = '\t';
            }
            else if (radioButtonImportSeperatorKomma.IsChecked == true)
            {
                if (textBoxImportSeperator.Text.Length == 1)
                {
                    seperator = textBoxImportSeperator.Text.ToArray().First();
                }
                else
                {
                    MessageBox.Show("Kein Trennzeichen ausgewählt", "Kein Trennzeichen ausgewählt", MessageBoxButton.OK, MessageBoxImage.Error);
                    return;
                }
            }
            else
            {
                MessageBox.Show("Kein Trennzeichen ausgewählt", "Kein Trennzeichen ausgewählt", MessageBoxButton.OK, MessageBoxImage.Error);
                return;
            }

            OpenFileDialog ofd = new OpenFileDialog();
            if (ofd.ShowDialog() != System.Windows.Forms.DialogResult.OK)
            {
                return;
            }
            textBlockImportFilename.Text = ofd.FileName;
            var ma = Mitarbeiter.ReadFile(ofd.FileName, seperator);
            mitarbeiter = new ObservableCollection<Mitarbeiter>(ma);

            System.Windows.Data.CollectionViewSource mitarbeiterViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("mitarbeiterViewSource")));

            mitarbeiterViewSource.Source = mitarbeiter;
        }

        private void buttonExportFilename_Click(object sender, RoutedEventArgs e)
        {
            char seperator;
            if (radioButtonExportSeperatorKomma.IsChecked == true)
            {
                seperator = ',';
            }
            else if (radioButtonExportSeperatorSemikolon.IsChecked == true)
            {
                seperator = ';';
            }
            else if (radioButtonExportSeperatorTab.IsChecked == true)
            {
                seperator = '\t';
            }
            else if (radioButtonExportSeperatorKomma.IsChecked == true)
            {
                if (textBoxExportSeperator.Text.Length == 1)
                {
                    seperator = textBoxExportSeperator.Text.ToArray().First();
                }
                else
                {
                    MessageBox.Show("Kein Trennzeichen ausgewählt", "Kein Trennzeichen ausgewählt", MessageBoxButton.OK, MessageBoxImage.Error);
                    return;
                }
            }
            else
            {
                MessageBox.Show("Kein Trennzeichen ausgewählt", "Kein Trennzeichen ausgewählt", MessageBoxButton.OK, MessageBoxImage.Error);
                return;
            }

            SaveFileDialog sfd = new SaveFileDialog();
            if(sfd.ShowDialog() != System.Windows.Forms.DialogResult.OK)
            {
                return;
            }

            textBlockExportFilename.Text = sfd.FileName;

            Mitarbeiter.CreateFile(mitarbeiter, sfd.FileName, seperator);
        }
    }
}

C#-Code

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace WpfCSVImportExport
{
    class Mitarbeiter
    {
        public string Vorname { get; set; }
        public string Nachname { get; set; }
        public string Geschlecht { get; set; }
        public DateTime Geburtstag { get; set; } = DateTime.Today;
        public string Beruf { get; set; }

        static readonly string[] properties =
        {
            nameof(Vorname),
            nameof(Nachname),
            nameof(Geschlecht),
            nameof(Geburtstag),
            nameof(Beruf),
        };

        static readonly Type Type = typeof(Mitarbeiter);
        static readonly Encoding Latin1 = Encoding.GetEncoding("ISO-8859-1");

        public static IEnumerable<Mitarbeiter> ReadFile(string filename, char seperator)
        {
            using (StreamReader sr = new StreamReader(filename, Latin1))
            {
                //sr.ReadLine();//Erste Zeile überspringen

                while (sr.Peek() != -1)
                {
                    string[] line = sr.ReadLine().Split(seperator);
                    Mitarbeiter ma = new Mitarbeiter();
                    for (int i = 0; i < properties.Length; i++)
                    {
                        string v = line.ElementAtOrDefault(i);

                        if (string.IsNullOrEmpty(v))
                        {
                            continue;
                        }
                        v = v.Trim();
                        object value = v;

                        if (properties[i] == nameof(Geburtstag))
                        {
                            DateTime date = DateTime.ParseExact(v, "dd.MM.yyyy", System.Globalization.CultureInfo.InvariantCulture);
                            if (DateTime.TryParseExact(v, "dd.MM.yyyy", System.Globalization.CultureInfo.InvariantCulture, System.Globalization.DateTimeStyles.None, out date))
                            {
                                value = date;
                            }
                            else
                            {
                                value = default(DateTime);
                            }
                        }

                        Type.GetProperty(properties[i]).SetValue(ma, value, null);
                    }

                    yield return ma;
                }
            }
        }

        public static void CreateFile(IEnumerable<Mitarbeiter> mitarbeiter, string filename, char seperator)
        {
            using (StreamWriter sw = new StreamWriter(filename, false, Latin1))
            {
                foreach (Mitarbeiter ma in mitarbeiter)
                {
                    string line = "";
                    for (int i = 0; i < properties.Length; i++)
                    {
                        object value = Type.GetProperty(properties[i]).GetValue(ma, null);
                        string v;
                        if (value == null)
                        {
                            v = "";
                        }
                        else
                        {
                            v = value.ToString();
                            if (value is DateTime)
                            {
                                DateTime date = (DateTime)value;
                                v = date.ToString("dd.MM.yyyy");
                            }
                        }

                        line += v + seperator;
                    }

                    sw.WriteLine(line);
                }
            }
        }
    }
}

XML-Code

<Window x:Class="WpfCSVImportExport.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:WpfCSVImportExport"
        mc:Ignorable="d"
        Title="CSV-Import-Export" Height="350" Width="525" Loaded="Window_Loaded">
    <Window.Resources>
        <CollectionViewSource x:Key="mitarbeiterViewSource" d:DesignSource="{d:DesignInstance {x:Type local:Mitarbeiter}, CreateList=True}"/>
    </Window.Resources>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="1*"/>
        </Grid.RowDefinitions>
        <Grid Grid.Row="0">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="1*"/>
                <ColumnDefinition Width="1*"/>
            </Grid.ColumnDefinitions>
            <GroupBox Grid.Column="0" Header="Import">
                <StackPanel>
                    <TextBlock x:Name="textBlockImportFilename" Text="ABC" Margin="10,10,0,0"/>
                    <StackPanel Orientation="Vertical" Margin="10,10,0,0">
                        <TextBlock Text="Trennzeichen"/>
                        <RadioButton x:Name="radioButtonImportSeperatorKomma" Content="Komma (,)" Margin="10,0,0,0"/>
                        <RadioButton x:Name="radioButtonImportSeperatorSemikolon" Content="Semikolon (;)" Margin="10,0,0,0" IsChecked="True"/>
                        <RadioButton x:Name="radioButtonImportSeperatorTab" Content="Tab" Margin="10,0,0,0"/>
                        <RadioButton x:Name="radioButtonImportSeperatorSonstige" Content="Sonstige" Margin="10,0,0,0"/>
                        <TextBox x:Name="textBoxImportSeperator" Width="30" MaxLength="1" IsEnabled="{Binding IsChecked, ElementName=radioButtonImportSeperatorSonstige}" Margin="10,0" HorizontalAlignment="Left" TextAlignment="Center"/>
                    </StackPanel>
                    <Button x:Name="buttonImportFilename" Content="Datei importieren" Margin="10" Click="buttonImportFilename_Click"/>
                </StackPanel>
            </GroupBox>
            <GroupBox Grid.Column="1" Header="Export">
                <StackPanel>
                    <TextBlock x:Name="textBlockExportFilename" Text="ABC" Margin="10,10,0,0"/>
                    <StackPanel Orientation="Vertical" Margin="10,10,0,0">
                        <TextBlock Text="Trennzeichen"/>
                        <RadioButton x:Name="radioButtonExportSeperatorKomma" Content="Komma (,)" Margin="10,0,0,0"/>
                        <RadioButton x:Name="radioButtonExportSeperatorSemikolon" Content="Semikolon (;)" Margin="10,0,0,0" IsChecked="True"/>
                        <RadioButton x:Name="radioButtonExportSeperatorTab" Content="Tab" Margin="10,0,0,0"/>
                        <RadioButton x:Name="radioButtonExportSeperatorSonstige" Content="Sonstige" Margin="10,0,0,0"/>
                        <TextBox x:Name="textBoxExportSeperator" Width="30" MaxLength="1" IsEnabled="{Binding IsChecked, ElementName=radioButtonExportSeperatorSonstige}" Margin="10,0" HorizontalAlignment="Left" TextAlignment="Center"/>
                    </StackPanel>
                    <Button x:Name="buttonExportFilename" Content="Datei exportieren" Margin="10" Click="buttonExportFilename_Click"/>
                </StackPanel>
            </GroupBox>
        </Grid>
        <Grid Grid.Row="1" DataContext="{StaticResource mitarbeiterViewSource}" Margin="10">
            <DataGrid x:Name="mitarbeiterDataGrid" AutoGenerateColumns="False" EnableRowVirtualization="True" ItemsSource="{Binding}" RowDetailsVisibilityMode="VisibleWhenSelected">
                <DataGrid.Columns>
                    <DataGridTextColumn x:Name="vornameColumn" Binding="{Binding Vorname}" Header="Vorname" Width="SizeToHeader"/>
                    <DataGridTextColumn x:Name="nachnameColumn" Binding="{Binding Nachname}" Header="Nachname" Width="SizeToHeader"/>
                    <DataGridTextColumn x:Name="geschlechtColumn" Binding="{Binding Geschlecht}" Header="Geschlecht" Width="SizeToHeader"/>
                    <DataGridTemplateColumn x:Name="geburtstagColumn" Header="Geburtstag" Width="SizeToHeader" SortMemberPath="Geburtstag">
                        <DataGridTemplateColumn.CellTemplate>
                            <DataTemplate>
                                <DatePicker SelectedDate="{Binding Geburtstag, Mode=TwoWay, NotifyOnValidationError=true, ValidatesOnExceptions=true}"/>
                            </DataTemplate>
                        </DataGridTemplateColumn.CellTemplate>
                    </DataGridTemplateColumn>
                    <DataGridTextColumn x:Name="berufColumn" Binding="{Binding Beruf}" Header="Beruf" Width="SizeToHeader"/>
                </DataGrid.Columns>
            </DataGrid>
        </Grid>
    </Grid>
</Window>