XML-Code

<Window x:Class="KartenMischen.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:KartenMischen"
        mc:Ignorable="d"
        Title="MainWindow" Height="580" Width="1080" Loaded="Window_Loaded"
        >
    <DockPanel>
        <UniformGrid DockPanel.Dock="Bottom" Rows="1" Height="Auto" HorizontalAlignment="Right">
            <Button Name="btn_Reset" Click="btn_Reset_Click">Reset</Button>
            <Button Name="btn_Shuffle" Click="btn_Shuffle_Click">Mischen</Button>
        </UniformGrid>
        
        <ScrollViewer DockPanel.Dock="Top">
            <ItemsControl Name="Board">
                <ItemsControl.ItemTemplate>
                    <DataTemplate>
                        <Image Source="{Binding}" Width="80"/>
                    </DataTemplate>
                </ItemsControl.ItemTemplate>
                <ItemsControl.ItemsPanel>
                    <ItemsPanelTemplate>
                        <WrapPanel/>
                    </ItemsPanelTemplate>
                </ItemsControl.ItemsPanel>
            </ItemsControl>
        </ScrollViewer>
    </DockPanel>
</Window>

C#-Code

using System;
using System.Collections.ObjectModel;
using System.Windows;
using System.Collections;

namespace KartenMischen {
  /// <summary>
  /// Interaktionslogik für MainWindow.xaml
  /// </summary>
  public partial class MainWindow : Window {
    readonly Random _random = new Random();

    public MainWindow() {
      InitializeComponent();
      Reset();
    }

    private void Window_Loaded(object sender, RoutedEventArgs e) {
      Shuffle();
    }

    private void btn_Reset_Click(object sender, RoutedEventArgs e) {
      Reset();
    }

    void Reset() {
      Board.ItemsSource = CreateDeck();
    }

    ObservableCollection<string> CreateDeck() {
      ObservableCollection<string> Deck = new ObservableCollection<string>();

      foreach(string suite in new string[] { "Clubs", "Spades", "Hearts", "Diamonds" }) {
        Deck.Add($"pack://application:,,,/KartenMischen;component/Resources/Cards/{suite}/Ace.png");
        for(int i = 2; i <= 10; i++) {
          Deck.Add($"pack://application:,,,/KartenMischen;component/Resources/Cards/{suite}/{i.ToString("00")}.png");
        }
        Deck.Add($"pack://application:,,,/KartenMischen;component/Resources/Cards/{suite}/Jack.png");
        Deck.Add($"pack://application:,,,/KartenMischen;component/Resources/Cards/{suite}/Queen.png");
        Deck.Add($"pack://application:,,,/KartenMischen;component/Resources/Cards/{suite}/King.png");
      }

      return Deck;
    }

    private void btn_Shuffle_Click(object sender, RoutedEventArgs e) {
      Shuffle();
    }

    void Shuffle() {
      for(int i = ((IList)Board.ItemsSource).Count - 1; i > -1; i--) {
        var Item = ((IList)Board.ItemsSource)[_random.Next(i)];
        ((IList)Board.ItemsSource).Remove(Item);
        ((IList)Board.ItemsSource).Add(Item);
      }
    }
  }
}

C#-Code

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace AUFGABEN {
    public partial class Form1 : Form {

        public Form1() {
            InitializeComponent();
        }

        private String[] _files;
        private Image[] _cards;

        private Random _rnd;

        private void Form1_Load(object sender, EventArgs e) {
            _rnd = new Random();

            LoadCardsFromDirectory();
            ReloadCards();
            ReloadDisplay();
        }

        /*
         * Funktionen
         */
        public void LoadCardsFromDirectory() {
            _files = System.IO.Directory.GetFiles("cards");
        }

        public void ReloadCards() {
            if (_files == null) return;

            _cards = new Image[_files.Length];

            for (int i = 0; i < _files.Length; i++) {
                _cards[i] = Image.FromFile(_files[i]);
            }
        }
        public void ReloadDisplay() {
            if (_cards == null) return;

            flPnlCards.Controls.Clear();

            for (int i = 0; i < _cards.Length; i++) {
                PictureBox pictureBox = new PictureBox();
                pictureBox.Size = new Size(79, 123);
                pictureBox.SizeMode = PictureBoxSizeMode.Zoom;
                pictureBox.Image = _cards[i];

                flPnlCards.Controls.Add(pictureBox);

            }
        }
        public void MixCards() {
            _files = _files.OrderBy(x => _rnd.Next()).ToArray();
        }
  
        /*
         * Buttons
         */
        private void btnMixCards_Click(object sender, EventArgs e) {
            MixCards();
            ReloadCards();
            ReloadDisplay();
        }

        private void btnReset_Click(object sender, EventArgs e) {
            LoadCardsFromDirectory();
            ReloadCards();
            ReloadDisplay();
        }
    }
}

C#-Code

namespace AUFGABEN {
    partial class Form1 {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing) {
            if (disposing && (components != null)) {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent() {
            this.groupBox1 = new System.Windows.Forms.GroupBox();
            this.flPnlCards = new System.Windows.Forms.FlowLayoutPanel();
            this.btnMixCards = new System.Windows.Forms.Button();
            this.btnReset = new System.Windows.Forms.Button();
            this.groupBox1.SuspendLayout();
            this.SuspendLayout();
            // 
            // groupBox1
            // 
            this.groupBox1.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom)
                        | System.Windows.Forms.AnchorStyles.Left)
                        | System.Windows.Forms.AnchorStyles.Right)));
            this.groupBox1.Controls.Add(this.flPnlCards);
            this.groupBox1.Location = new System.Drawing.Point(12, 45);
            this.groupBox1.Name = "groupBox1";
            this.groupBox1.Size = new System.Drawing.Size(600, 289);
            this.groupBox1.TabIndex = 0;
            this.groupBox1.TabStop = false;
            this.groupBox1.Text = "Karten";
            // 
            // flPnlCards
            // 
            this.flPnlCards.AutoScroll = true;
            this.flPnlCards.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
            this.flPnlCards.Dock = System.Windows.Forms.DockStyle.Fill;
            this.flPnlCards.Location = new System.Drawing.Point(3, 16);
            this.flPnlCards.Name = "flPnlCards";
            this.flPnlCards.Size = new System.Drawing.Size(594, 270);
            this.flPnlCards.TabIndex = 0;
            // 
            // btnMixCards
            // 
            this.btnMixCards.Location = new System.Drawing.Point(12, 12);
            this.btnMixCards.Name = "btnMixCards";
            this.btnMixCards.Size = new System.Drawing.Size(75, 23);
            this.btnMixCards.TabIndex = 1;
            this.btnMixCards.Text = "Mischen";
            this.btnMixCards.UseVisualStyleBackColor = true;
            this.btnMixCards.Click += new System.EventHandler(this.btnMixCards_Click);
            // 
            // btnReset
            // 
            this.btnReset.Location = new System.Drawing.Point(93, 12);
            this.btnReset.Name = "btnReset";
            this.btnReset.Size = new System.Drawing.Size(75, 23);
            this.btnReset.TabIndex = 2;
            this.btnReset.Text = "Reset";
            this.btnReset.UseVisualStyleBackColor = true;
            this.btnReset.Click += new System.EventHandler(this.btnReset_Click);
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(624, 346);
            this.Controls.Add(this.btnReset);
            this.Controls.Add(this.btnMixCards);
            this.Controls.Add(this.groupBox1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.groupBox1.ResumeLayout(false);
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.GroupBox groupBox1;
        private System.Windows.Forms.FlowLayoutPanel flPnlCards;
        private System.Windows.Forms.Button btnMixCards;
        private System.Windows.Forms.Button btnReset;
    }
}

C#-Code

<Window x:Class="ShuffleCards.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:ShuffleCards"
        mc:Ignorable="d"
        Title="ShuffleCards" Height="700" Width="1050" FontFamily="Courier New" WindowState="Normal" WindowStartupLocation="CenterScreen">
    <Grid Background="{DynamicResource {x:Static SystemColors.ActiveCaptionBrushKey}}">
        <Grid.RowDefinitions>
            <RowDefinition Height="35"/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <StackPanel Margin="0" Orientation="Horizontal">
            <Button x:Name="button0" Content=" reset   " Width="75" Margin="5" Click="button0_Click"/>
            <Button x:Name="button1" Content=" shuffle " Width="75" Margin="5" Click="button1_Click"/>
            <Label x:Name="lb_version" Content=" version 2018/01/14   2018/01/17" VerticalContentAlignment="Center" FontWeight="Bold" 
        </StackPanel>
        <GroupBox x:Name="groupBox" Header=" card ground " Grid.Row="1" Margin="5">
            <Grid Margin="5">
                
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                    <ColumnDefinition Width="1*"/>
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="1*"/>
                    <RowDefinition Height="1*"/>
                    <RowDefinition Height="1*"/>
                    <RowDefinition Height="1*"/>
                </Grid.RowDefinitions>
                
                <Image x:Name="image000" Margin="5" Grid.Row="0" Grid.Column="0" />
                <Image x:Name="image001" Margin="5" Grid.Row="0" Grid.Column="1" />
                <Image x:Name="image002" Margin="5" Grid.Row="0" Grid.Column="2" />
                <Image x:Name="image003" Margin="5" Grid.Row="0" Grid.Column="3" />
                <Image x:Name="image004" Margin="5" Grid.Row="0" Grid.Column="4" />
                <Image x:Name="image005" Margin="5" Grid.Row="0" Grid.Column="5" />
                <Image x:Name="image006" Margin="5" Grid.Row="0" Grid.Column="6" />
                <Image x:Name="image007" Margin="5" Grid.Row="0" Grid.Column="7" />
                <Image x:Name="image008" Margin="5" Grid.Row="0" Grid.Column="8" />
                <Image x:Name="image009" Margin="5" Grid.Row="0" Grid.Column="9" />
                <Image x:Name="image010" Margin="5" Grid.Row="0" Grid.Column="10" />
                <Image x:Name="image011" Margin="5" Grid.Row="0" Grid.Column="11" />
                <Image x:Name="image012" Margin="5" Grid.Row="0" Grid.Column="12" />

                <Image x:Name="image100" Margin="5" Grid.Row="1" Grid.Column="0" />
                <Image x:Name="image101" Margin="5" Grid.Row="1" Grid.Column="1" />
                <Image x:Name="image102" Margin="5" Grid.Row="1" Grid.Column="2" />
                <Image x:Name="image103" Margin="5" Grid.Row="1" Grid.Column="3" />
                <Image x:Name="image104" Margin="5" Grid.Row="1" Grid.Column="4" />
                <Image x:Name="image105" Margin="5" Grid.Row="1" Grid.Column="5" />
                <Image x:Name="image106" Margin="5" Grid.Row="1" Grid.Column="6" />
                <Image x:Name="image107" Margin="5" Grid.Row="1" Grid.Column="7" />
                <Image x:Name="image108" Margin="5" Grid.Row="1" Grid.Column="8" />
                <Image x:Name="image109" Margin="5" Grid.Row="1" Grid.Column="9" />
                <Image x:Name="image110" Margin="5" Grid.Row="1" Grid.Column="10" />
                <Image x:Name="image111" Margin="5" Grid.Row="1" Grid.Column="11" />
                <Image x:Name="image112" Margin="5" Grid.Row="1" Grid.Column="12" />

                <Image x:Name="image200" Margin="5" Grid.Row="2" Grid.Column="0" />
                <Image x:Name="image201" Margin="5" Grid.Row="2" Grid.Column="1" />
                <Image x:Name="image202" Margin="5" Grid.Row="2" Grid.Column="2" />
                <Image x:Name="image203" Margin="5" Grid.Row="2" Grid.Column="3" />
                <Image x:Name="image204" Margin="5" Grid.Row="2" Grid.Column="4" />
                <Image x:Name="image205" Margin="5" Grid.Row="2" Grid.Column="5" />
                <Image x:Name="image206" Margin="5" Grid.Row="2" Grid.Column="6" />
                <Image x:Name="image207" Margin="5" Grid.Row="2" Grid.Column="7" />
                <Image x:Name="image208" Margin="5" Grid.Row="2" Grid.Column="8" />
                <Image x:Name="image209" Margin="5" Grid.Row="2" Grid.Column="9" />
                <Image x:Name="image210" Margin="5" Grid.Row="2" Grid.Column="10" />
                <Image x:Name="image211" Margin="5" Grid.Row="2" Grid.Column="11" />
                <Image x:Name="image212" Margin="5" Grid.Row="2" Grid.Column="12" />

                <Image x:Name="image300" Margin="5" Grid.Row="3" Grid.Column="0" />
                <Image x:Name="image301" Margin="5" Grid.Row="3" Grid.Column="1" />
                <Image x:Name="image302" Margin="5" Grid.Row="3" Grid.Column="2" />
                <Image x:Name="image303" Margin="5" Grid.Row="3" Grid.Column="3" />
                <Image x:Name="image304" Margin="5" Grid.Row="3" Grid.Column="4" />
                <Image x:Name="image305" Margin="5" Grid.Row="3" Grid.Column="5" />
                <Image x:Name="image306" Margin="5" Grid.Row="3" Grid.Column="6" />
                <Image x:Name="image307" Margin="5" Grid.Row="3" Grid.Column="7" />
                <Image x:Name="image308" Margin="5" Grid.Row="3" Grid.Column="8" />
                <Image x:Name="image309" Margin="5" Grid.Row="3" Grid.Column="9" />
                <Image x:Name="image310" Margin="5" Grid.Row="3" Grid.Column="10" />
                <Image x:Name="image311" Margin="5" Grid.Row="3" Grid.Column="11" />
                <Image x:Name="image312" Margin="5" Grid.Row="3" Grid.Column="12" />
                
            </Grid>
        </GroupBox>
    </Grid>
</Window>

C#-Code

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace ShuffleCards    {
    public partial class MainWindow : Window    {
        public enum Cases { BackSide, Reset, Mix };
        
        public void set_images(Cases icase)   {
            Image[] Im = new Image[]    {
                this.image000, this.image001, this.image002, this.image003, this.image004, this.image005,
                this.image006, this.image007, this.image008, this.image009, this.image010, this.image011,
                this.image012,

                this.image100, this.image101, this.image102, this.image103, this.image104, this.image105,
                this.image106, this.image107, this.image108, this.image109, this.image110, this.image111,
                this.image112,

                this.image200, this.image201, this.image202, this.image203, this.image204, this.image205,
                this.image206, this.image207, this.image208, this.image209, this.image210, this.image211,
                this.image212,

                this.image300, this.image301, this.image302, this.image303, this.image304, this.image305,
                this.image306, this.image307, this.image308, this.image309, this.image310, this.image311,
                this.image312
            };
            int count_cards = Im.Length;
            Shuffle shufflecards = null;
            switch (icase)    {
                case Cases.BackSide:
                    string s0 = @"pics\back.png";
                    ImageSource imageSource = new BitmapImage(new Uri(s0, 
                        UriKind.RelativeOrAbsolute));
                    foreach (Image im in Im)
                        im.Source = imageSource;
                    return;
                case Cases.Reset:                    
                    shufflecards = new Shuffle(count_cards, bo_reset: true);
                    break;
                case Cases.Mix:
                    shufflecards = new Shuffle(count_cards, bo_reset: false);                    
                    break;
            };
            string[] uris = new string[count_cards];
            string s00 = @"pics\";
            int zeiger = 0;
            for (var i = 0; i < uris.Length; i++)    {
                if (i == 11 || i == 24 || i == 37 || i == 50)
                    zeiger++;
                uris[i] = s00 + zeiger.ToString("00") + ".png";                
                zeiger++;
            };
            for (var i = 0; i < uris.Length; i++)
                Im[i].Source = new BitmapImage(new Uri(uris[shufflecards.Mix[i]], 
                    UriKind.RelativeOrAbsolute));
        }

        public MainWindow()    {
            InitializeComponent();
            set_images((int)Cases.BackSide);
        }

        private void button0_Click(object sender, RoutedEventArgs e) => set_images(Cases.Reset);

        private void button1_Click(object sender, RoutedEventArgs e) => set_images(Cases.Mix);

    }
}

C#-Code

using System;
using System.Collections.Generic;
using System.Text;

namespace ShuffleCards   {
    public class Shuffle    {

        private Random rand;
        private int count_cards;
        private bool bo_reset;

        public int[] Mix { get; private set; }

        //Fisher - Yates shuffle
        public Shuffle(int count_cards, bool bo_reset = false)    {
            rand = new Random();
            this.count_cards = count_cards;
            this.bo_reset = bo_reset;
            this.Mix = new int[count_cards];
            for (var i = 0; i < count_cards; i++)
                this.Mix[i] = i;
            if (!bo_reset)
                mix();           
        }

        private void mix()
        {           
            Stack<int> stack = new Stack<int>();
            for (var j = Mix.Length - 1; j > 0; j--)
            {
                int jj = rand.Next(j + 1);
                stack.Push(Mix[jj]);
                Mix[jj] = Mix[j];
                Mix[j] = stack.Pop();
            }
        }
    }
}