[ADDED] client and server project (both are WPF projects))

Client/App.xaml

@@ -0,0 +1,9 @@
+<Application x:Class="Client.App"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:local="clr-namespace:Client"
+             StartupUri="MainWindow.xaml">
+    <Application.Resources>
+         
+    </Application.Resources>
+</Application>

Client/App.xaml.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Configuration;
+using System.Data;
+using System.Linq;
+using System.Threading.Tasks;
+using System.Windows;
+
+namespace Client
+{
+    /// <summary>
+    /// Interaction logic for App.xaml
+    /// </summary>
+    public partial class App : Application
+    {
+    }
+}

Client/AssemblyInfo.cs

@@ -0,0 +1,10 @@
+using System.Windows;
+
+[assembly: ThemeInfo(
+    ResourceDictionaryLocation.None, //where theme specific resource dictionaries are located
+                                     //(used if a resource is not found in the page,
+                                     // or application resource dictionaries)
+    ResourceDictionaryLocation.SourceAssembly //where the generic resource dictionary is located
+                                              //(used if a resource is not found in the page,
+                                              // app, or any theme specific resource dictionaries)
+)]

Client/Client.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
+
+  <PropertyGroup>
+    <OutputType>WinExe</OutputType>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <UseWPF>true</UseWPF>
+  </PropertyGroup>
+
+</Project>

Client/MainWindow.xaml

@@ -0,0 +1,12 @@
+<Window x:Class="Client.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:Client"
+        mc:Ignorable="d"
+        Title="MainWindow" Height="450" Width="800">
+    <Grid>
+
+    </Grid>
+</Window>

Client/MainWindow.xaml.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Data;
+using System.Windows.Documents;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using System.Windows.Navigation;
+using System.Windows.Shapes;
+
+namespace Client
+{
+    /// <summary>
+    /// Interaction logic for MainWindow.xaml
+    /// </summary>
+    public partial class MainWindow : Window
+    {
+        public MainWindow()
+        {
+            InitializeComponent();
+        }
+    }
+}

Eindproject/Eindproject.sln

@@ -3,7 +3,11 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 16
 VisualStudioVersion = 16.0.30517.126
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Eindproject", "Eindproject.csproj", "{F9D948F4-BD6F-4E5A-B7D1-59C6AA04B308}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Eindproject", "Eindproject.csproj", "{F9D948F4-BD6F-4E5A-B7D1-59C6AA04B308}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Server", "..\Server\Server.csproj", "{67A9BF1A-D317-47CA-9F07-C3480D1360FF}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Client", "..\Client\Client.csproj", "{83768EDB-097E-4089-A5DE-208CB252D1A0}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -15,6 +19,14 @@ Global
 		{F9D948F4-BD6F-4E5A-B7D1-59C6AA04B308}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{F9D948F4-BD6F-4E5A-B7D1-59C6AA04B308}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{F9D948F4-BD6F-4E5A-B7D1-59C6AA04B308}.Release|Any CPU.Build.0 = Release|Any CPU
+		{67A9BF1A-D317-47CA-9F07-C3480D1360FF}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{67A9BF1A-D317-47CA-9F07-C3480D1360FF}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{67A9BF1A-D317-47CA-9F07-C3480D1360FF}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{67A9BF1A-D317-47CA-9F07-C3480D1360FF}.Release|Any CPU.Build.0 = Release|Any CPU
+		{83768EDB-097E-4089-A5DE-208CB252D1A0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{83768EDB-097E-4089-A5DE-208CB252D1A0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{83768EDB-097E-4089-A5DE-208CB252D1A0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{83768EDB-097E-4089-A5DE-208CB252D1A0}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

Server/App.xaml

@@ -0,0 +1,9 @@
+<Application x:Class="Server.App"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:local="clr-namespace:Server"
+             StartupUri="MainWindow.xaml">
+    <Application.Resources>
+         
+    </Application.Resources>
+</Application>

Server/App.xaml.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Configuration;
+using System.Data;
+using System.Linq;
+using System.Threading.Tasks;
+using System.Windows;
+
+namespace Server
+{
+    /// <summary>
+    /// Interaction logic for App.xaml
+    /// </summary>
+    public partial class App : Application
+    {
+    }
+}

Server/AssemblyInfo.cs

@@ -0,0 +1,10 @@
+using System.Windows;
+
+[assembly: ThemeInfo(
+    ResourceDictionaryLocation.None, //where theme specific resource dictionaries are located
+                                     //(used if a resource is not found in the page,
+                                     // or application resource dictionaries)
+    ResourceDictionaryLocation.SourceAssembly //where the generic resource dictionary is located
+                                              //(used if a resource is not found in the page,
+                                              // app, or any theme specific resource dictionaries)
+)]

Server/MainWindow.xaml

@@ -0,0 +1,12 @@
+<Window x:Class="Server.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:Server"
+        mc:Ignorable="d"
+        Title="MainWindow" Height="450" Width="800">
+    <Grid>
+
+    </Grid>
+</Window>

Server/MainWindow.xaml.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Data;
+using System.Windows.Documents;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using System.Windows.Navigation;
+using System.Windows.Shapes;
+
+namespace Server
+{
+    /// <summary>
+    /// Interaction logic for MainWindow.xaml
+    /// </summary>
+    public partial class MainWindow : Window
+    {
+        public MainWindow()
+        {
+            InitializeComponent();
+        }
+    }
+}

Server/Server.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">
+
+  <PropertyGroup>
+    <OutputType>WinExe</OutputType>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <UseWPF>true</UseWPF>
+  </PropertyGroup>
+
+</Project>