From 2a474aac0a41c8e920a363ced6b21fc40b263d77 Mon Sep 17 00:00:00 2001
From: "Valeriano A.R" <valen.alfonso@protonmail.com>
Date: Mon, 22 May 2023 03:25:56 +0200
Subject: [PATCH] Enabled nullable checks and fix nullability warnings.

---
 VAR.WebFormsCore.TestWebApp/FrmDefault.cs     |  9 ++--
 VAR.WebFormsCore.TestWebApp/Program.cs        |  3 --
 VAR.WebFormsCore.TestWebApp/Startup.cs        |  3 --
 VAR.WebFormsCore.sln.DotSettings              |  2 +
 VAR.WebFormsCore/Code/Bundler.cs              | 14 +++---
 VAR.WebFormsCore/Code/ExtensionMethods.cs     |  2 +-
 VAR.WebFormsCore/Code/GlobalConfig.cs         | 43 ++++++++++++++++---
 VAR.WebFormsCore/Code/GlobalErrorHandler.cs   |  2 +-
 .../Code/GlobalRouterMiddleware.cs            | 10 ++---
 VAR.WebFormsCore/Code/MultiLang.cs            | 10 ++---
 VAR.WebFormsCore/Code/ServerHelpers.cs        |  2 +-
 VAR.WebFormsCore/Code/StaticFileHelper.cs     |  2 +-
 VAR.WebFormsCore/Controls/Button.cs           |  4 +-
 VAR.WebFormsCore/Controls/CTextBox.cs         | 38 +++++++++-------
 VAR.WebFormsCore/Controls/Control.cs          | 43 +++++++++++--------
 VAR.WebFormsCore/Controls/HiddenField.cs      |  4 +-
 VAR.WebFormsCore/Controls/HtmlForm.cs         | 15 ++++---
 VAR.WebFormsCore/Controls/HtmlHead.cs         |  2 +-
 VAR.WebFormsCore/Controls/HtmlMeta.cs         |  6 +--
 VAR.WebFormsCore/Controls/HyperLink.cs        |  4 +-
 VAR.WebFormsCore/Controls/LiteralControl.cs   |  2 +-
 VAR.WebFormsCore/Controls/TextBox.cs          |  4 +-
 VAR.WebFormsCore/Pages/FormUtils.cs           |  2 +-
 VAR.WebFormsCore/Pages/FrmError.cs            |  4 +-
 VAR.WebFormsCore/Pages/Page.cs                |  4 +-
 VAR.WebFormsCore/Pages/PageCommon.cs          | 42 ++++++++++--------
 VAR.WebFormsCore/VAR.WebFormsCore.csproj      |  1 +
 27 files changed, 160 insertions(+), 117 deletions(-)
 create mode 100644 VAR.WebFormsCore.sln.DotSettings

diff --git a/VAR.WebFormsCore.TestWebApp/FrmDefault.cs b/VAR.WebFormsCore.TestWebApp/FrmDefault.cs
index dbf385a..ea99d82 100644
--- a/VAR.WebFormsCore.TestWebApp/FrmDefault.cs
+++ b/VAR.WebFormsCore.TestWebApp/FrmDefault.cs
@@ -1,4 +1,3 @@
-using System;
 using VAR.WebFormsCore.Code;
 using VAR.WebFormsCore.Controls;
 using VAR.WebFormsCore.Pages;
@@ -7,9 +6,9 @@ namespace VAR.WebFormsCore.TestWebApp;
 
 public class FrmDefault: PageCommon
 {
-    private CTextBox _txtText = new CTextBox { ID = "txtText", CssClassExtra = "width150px", AllowEmpty = false };
-    private Button _btnTest = new Button { ID = "btnTest", };
-    private Label _lblMessage = new Label { ID = "lblMessage", };
+    private readonly CTextBox _txtText = new() { ID = "txtText", CssClassExtra = "width150px", AllowEmpty = false };
+    private readonly Button _btnTest = new() { ID = "btnTest", };
+    private readonly Label _lblMessage = new() { ID = "lblMessage", };
     
     public FrmDefault()
     {
@@ -17,7 +16,7 @@ public class FrmDefault: PageCommon
         Init += FrmLogin_Init;
     }
     
-    private void FrmLogin_Init(object sender, EventArgs e)
+    private void FrmLogin_Init(object? sender, EventArgs e)
     {
         InitializeControls();
     }
diff --git a/VAR.WebFormsCore.TestWebApp/Program.cs b/VAR.WebFormsCore.TestWebApp/Program.cs
index 0b4c917..0a416e1 100644
--- a/VAR.WebFormsCore.TestWebApp/Program.cs
+++ b/VAR.WebFormsCore.TestWebApp/Program.cs
@@ -1,6 +1,3 @@
-using Microsoft.AspNetCore.Hosting;
-using Microsoft.Extensions.Hosting;
-
 namespace VAR.WebFormsCore.TestWebApp
 {
     public class Program
diff --git a/VAR.WebFormsCore.TestWebApp/Startup.cs b/VAR.WebFormsCore.TestWebApp/Startup.cs
index 24ff415..71fc70d 100644
--- a/VAR.WebFormsCore.TestWebApp/Startup.cs
+++ b/VAR.WebFormsCore.TestWebApp/Startup.cs
@@ -1,7 +1,4 @@
-using Microsoft.AspNetCore.Builder;
-using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Server.Kestrel.Core;
-using Microsoft.Extensions.DependencyInjection;
 using VAR.WebFormsCore.Code;
 
 namespace VAR.WebFormsCore.TestWebApp
diff --git a/VAR.WebFormsCore.sln.DotSettings b/VAR.WebFormsCore.sln.DotSettings
new file mode 100644
index 0000000..d18f71a
--- /dev/null
+++ b/VAR.WebFormsCore.sln.DotSettings
@@ -0,0 +1,2 @@
+<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/Abbreviations/=ID/@EntryIndexedValue">ID</s:String></wpf:ResourceDictionary>
\ No newline at end of file
diff --git a/VAR.WebFormsCore/Code/Bundler.cs b/VAR.WebFormsCore/Code/Bundler.cs
index 9cec531..e8f8a4c 100644
--- a/VAR.WebFormsCore/Code/Bundler.cs
+++ b/VAR.WebFormsCore/Code/Bundler.cs
@@ -11,11 +11,11 @@ namespace VAR.WebFormsCore.Code
     {
         #region Declarations
 
-        private readonly Assembly _assembly;
-        private readonly string _assemblyNamespace;
-        private List<string> _assemblyFiles;
-        private readonly string _absolutePath;
-        private List<string> _absoluteFiles;
+        private readonly Assembly? _assembly;
+        private readonly string? _assemblyNamespace;
+        private List<string>? _assemblyFiles;
+        private readonly string? _absolutePath;
+        private List<string>? _absoluteFiles;
 
         #endregion Declarations
 
@@ -62,7 +62,7 @@ namespace VAR.WebFormsCore.Code
 
         #region Creator
 
-        public Bundler(Assembly assembly = null, string assemblyNamespace = null, string absolutePath = null)
+        public Bundler(Assembly? assembly = null, string? assemblyNamespace = null, string? absolutePath = null)
         {
             _assembly = assembly;
             _assemblyNamespace = assemblyNamespace;
@@ -81,7 +81,7 @@ namespace VAR.WebFormsCore.Code
             response.ContentType = contentType;
             foreach (string fileName in AssemblyFiles)
             {
-                Stream resourceStream = _assembly.GetManifestResourceStream(fileName);
+                Stream? resourceStream = _assembly?.GetManifestResourceStream(fileName);
                 if (resourceStream != null)
                 {
                     string fileContent = new StreamReader(resourceStream).ReadToEnd();
diff --git a/VAR.WebFormsCore/Code/ExtensionMethods.cs b/VAR.WebFormsCore/Code/ExtensionMethods.cs
index 4ce78eb..7e1e919 100644
--- a/VAR.WebFormsCore/Code/ExtensionMethods.cs
+++ b/VAR.WebFormsCore/Code/ExtensionMethods.cs
@@ -9,7 +9,7 @@ namespace VAR.WebFormsCore.Code
     {
         #region HttpContext
 
-        public static string GetRequestParm(this HttpContext context, string parm)
+        public static string? GetRequestParm(this HttpContext context, string parm)
         {
             if (context.Request.Method == "POST")
             {
diff --git a/VAR.WebFormsCore/Code/GlobalConfig.cs b/VAR.WebFormsCore/Code/GlobalConfig.cs
index c6ff1fe..b89e953 100644
--- a/VAR.WebFormsCore/Code/GlobalConfig.cs
+++ b/VAR.WebFormsCore/Code/GlobalConfig.cs
@@ -1,32 +1,61 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
+using Microsoft.AspNetCore.Http;
 
 namespace VAR.WebFormsCore.Code
 {
     public static class GlobalConfig
     {
-        private static IGlobalConfig _globalConfig;
+        private static IGlobalConfig? _globalConfig;
 
         public static IGlobalConfig Get()
         {
             if (_globalConfig != null) { return _globalConfig; }
 
             Type iGlobalConfig = typeof(IGlobalConfig);
-            Type foundGlobalConfig = AppDomain.CurrentDomain
+            Type? foundGlobalConfig = AppDomain.CurrentDomain
                 .GetAssemblies()
-                .SelectMany(
-                    x =>
-                        x.GetTypes()
-                )
+                .SelectMany(x => x.GetTypes())
                 .FirstOrDefault(
                     x =>
                         x.IsAbstract == false &&
                         x.IsInterface == false &&
+                        x.IsPublic &&
                         iGlobalConfig.IsAssignableFrom(x)
                 );
-            _globalConfig = ObjectActivator.CreateInstance(foundGlobalConfig) as IGlobalConfig;
+            if(foundGlobalConfig != null)
+            {
+                _globalConfig = ObjectActivator.CreateInstance(foundGlobalConfig) as IGlobalConfig;
+            }
+            
+            if(_globalConfig == null)
+            {
+                _globalConfig = new DefaultGlobalConfig();
+            }
 
             return _globalConfig;
         }
+
+        // TODO: Better default global config
+        private class DefaultGlobalConfig : IGlobalConfig
+        {
+            public string Title { get; } = string.Empty;
+            public string TitleSeparator { get; } = string.Empty;
+            public string Author { get; } = string.Empty;
+            public string Copyright { get; } = string.Empty;
+            public string DefaultHandler { get; } = string.Empty;
+            public string LoginHandler { get; } = string.Empty;
+            public List<string> AllowedExtensions { get; } = new List<string>();
+            
+            public bool IsUserAuthenticated(HttpContext context)
+            {
+                return false;
+            }
+
+            public void UserUnauthenticate(HttpContext context)
+            {
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/VAR.WebFormsCore/Code/GlobalErrorHandler.cs b/VAR.WebFormsCore/Code/GlobalErrorHandler.cs
index ca1a76e..8b74a26 100644
--- a/VAR.WebFormsCore/Code/GlobalErrorHandler.cs
+++ b/VAR.WebFormsCore/Code/GlobalErrorHandler.cs
@@ -17,7 +17,7 @@ namespace VAR.WebFormsCore.Code
 
                 StringBuilder sbOutput = new StringBuilder();
                 sbOutput.Append("<h2>Internal error</h2>");
-                Exception exAux = ex;
+                Exception? exAux = ex;
                 while (exAux != null)
                 {
                     sbOutput.AppendFormat("<p><b>Message:</b> {0}</p>", exAux.Message);
diff --git a/VAR.WebFormsCore/Code/GlobalRouterMiddleware.cs b/VAR.WebFormsCore/Code/GlobalRouterMiddleware.cs
index e11203e..a3b9d0c 100644
--- a/VAR.WebFormsCore/Code/GlobalRouterMiddleware.cs
+++ b/VAR.WebFormsCore/Code/GlobalRouterMiddleware.cs
@@ -68,7 +68,7 @@ namespace VAR.WebFormsCore.Code
                 }
             }
 
-            IHttpHandler handler = GetHandler(file);
+            IHttpHandler? handler = GetHandler(file);
             if (handler == null)
             {
                 // TODO: FrmNotFound
@@ -81,16 +81,16 @@ namespace VAR.WebFormsCore.Code
 
         private static readonly Dictionary<string, Type> Handlers = new Dictionary<string, Type>();
 
-        private static IHttpHandler GetHandler(string typeName)
+        private static IHttpHandler? GetHandler(string typeName)
         {
             if (string.IsNullOrEmpty(typeName)) { return null; }
 
-            Type type;
+            Type? type;
             lock (Handlers)
             {
                 if (Handlers.TryGetValue(typeName, out type))
                 {
-                    IHttpHandler handler = ObjectActivator.CreateInstance(type) as IHttpHandler;
+                    IHttpHandler? handler = ObjectActivator.CreateInstance(type) as IHttpHandler;
                     return handler;
                 }
             }
@@ -129,7 +129,7 @@ namespace VAR.WebFormsCore.Code
             // Use found type
             if (type != null)
             {
-                IHttpHandler handler = ObjectActivator.CreateInstance(type) as IHttpHandler;
+                IHttpHandler? handler = ObjectActivator.CreateInstance(type) as IHttpHandler;
                 if (handler != null)
                 {
                     lock (Handlers)
diff --git a/VAR.WebFormsCore/Code/MultiLang.cs b/VAR.WebFormsCore/Code/MultiLang.cs
index 4e4de1d..56b0ab5 100644
--- a/VAR.WebFormsCore/Code/MultiLang.cs
+++ b/VAR.WebFormsCore/Code/MultiLang.cs
@@ -12,7 +12,7 @@ namespace VAR.WebFormsCore.Code
             string privatePath = Path.Combine(currentDir, baseDir);
             while (Directory.Exists(privatePath) == false)
             {
-                DirectoryInfo dirInfo = Directory.GetParent(currentDir);
+                DirectoryInfo? dirInfo = Directory.GetParent(currentDir);
                 if (dirInfo == null) { break; }
 
                 currentDir = dirInfo.FullName;
@@ -22,11 +22,11 @@ namespace VAR.WebFormsCore.Code
             return Path.Combine(privatePath, fileName);
         }
 
-        private static Dictionary<string, Dictionary<string, object>> _literals;
+        private static Dictionary<string, Dictionary<string, object>?>? _literals;
 
         private static void InitializeLiterals()
         {
-            _literals = new Dictionary<string, Dictionary<string, object>>();
+            _literals = new Dictionary<string, Dictionary<string, object>?>();
 
             JsonParser jsonParser = new JsonParser();
             foreach (string lang in new[] {"en", "es"})
@@ -75,7 +75,7 @@ namespace VAR.WebFormsCore.Code
             return DefaultLanguage;
         }
 
-        public static string GetLiteral(string resource, string culture = null)
+        public static string GetLiteral(string resource, string? culture = null)
         {
             if (_literals == null) { InitializeLiterals(); }
 
@@ -83,7 +83,7 @@ namespace VAR.WebFormsCore.Code
 
             if (_literals == null || _literals.ContainsKey(culture) == false) { return resource; }
 
-            Dictionary<string, object> literalCurrentCulture = _literals[culture];
+            Dictionary<string, object>? literalCurrentCulture = _literals[culture];
 
             if (literalCurrentCulture == null || literalCurrentCulture.ContainsKey(resource) == false)
             {
diff --git a/VAR.WebFormsCore/Code/ServerHelpers.cs b/VAR.WebFormsCore/Code/ServerHelpers.cs
index dcc0fd6..b576473 100644
--- a/VAR.WebFormsCore/Code/ServerHelpers.cs
+++ b/VAR.WebFormsCore/Code/ServerHelpers.cs
@@ -5,7 +5,7 @@ namespace VAR.WebFormsCore.Code
 {
     public static class ServerHelpers
     {
-        private static string _contentRoot;
+        private static string? _contentRoot;
         public static void SetContentRoot(string contentRoot) { _contentRoot = contentRoot; }
 
         public static string MapContentPath(string path)
diff --git a/VAR.WebFormsCore/Code/StaticFileHelper.cs b/VAR.WebFormsCore/Code/StaticFileHelper.cs
index 42c84a0..7642e9c 100644
--- a/VAR.WebFormsCore/Code/StaticFileHelper.cs
+++ b/VAR.WebFormsCore/Code/StaticFileHelper.cs
@@ -71,7 +71,7 @@ namespace VAR.WebFormsCore.Code
         public static async void ResponseStaticFile(HttpContext context, string filePath)
         {
             string extension = Path.GetExtension(filePath).ToLower();
-            MimeTypeByExtension.TryGetValue(extension, out string contentType);
+            MimeTypeByExtension.TryGetValue(extension, out string? contentType);
 
             if (string.IsNullOrEmpty(contentType) == false) { context.Response.ContentType = contentType; }
 
diff --git a/VAR.WebFormsCore/Controls/Button.cs b/VAR.WebFormsCore/Controls/Button.cs
index 3e566d0..ca42558 100644
--- a/VAR.WebFormsCore/Controls/Button.cs
+++ b/VAR.WebFormsCore/Controls/Button.cs
@@ -15,11 +15,11 @@ namespace VAR.WebFormsCore.Controls
             set => _text = value;
         }
         
-        public string OnClientClick { get; set; }
+        public string OnClientClick { get; set; } = string.Empty;
         
         public string CommandArgument { get; set; } = string.Empty;
 
-        public event EventHandler Click;
+        public event EventHandler? Click;
 
         protected override void Render(TextWriter textWriter)
         {
diff --git a/VAR.WebFormsCore/Controls/CTextBox.cs b/VAR.WebFormsCore/Controls/CTextBox.cs
index caefacb..28c9fc2 100644
--- a/VAR.WebFormsCore/Controls/CTextBox.cs
+++ b/VAR.WebFormsCore/Controls/CTextBox.cs
@@ -11,7 +11,7 @@ namespace VAR.WebFormsCore.Controls
 
         private readonly TextBox _txtContent = new TextBox();
 
-        private HiddenField _hidSize;
+        private HiddenField? _hidSize;
 
         private const string CssClassBase = "textbox";
         private string _cssClassExtra = "";
@@ -22,7 +22,7 @@ namespace VAR.WebFormsCore.Controls
 
         private bool _markedInvalid;
 
-        private Control _nextFocusOnEnter;
+        private Control? _nextFocusOnEnter;
 
         private bool _keepSize;
 
@@ -54,7 +54,7 @@ namespace VAR.WebFormsCore.Controls
             set => _markedInvalid = value;
         }
 
-        public Control NextFocusOnEnter
+        public Control? NextFocusOnEnter
         {
             get => _nextFocusOnEnter;
             set => _nextFocusOnEnter = value;
@@ -88,7 +88,7 @@ namespace VAR.WebFormsCore.Controls
             PreRender += CTextbox_PreRender;
         }
 
-        private void CTextBox_Init(object sender, EventArgs e)
+        private void CTextBox_Init(object? sender, EventArgs e)
         {
             Controls.Add(_txtContent);
 
@@ -103,7 +103,7 @@ namespace VAR.WebFormsCore.Controls
                 string strCfgName = $"{this.ClientID}_cfg";
                 Dictionary<string, object> cfg = new Dictionary<string, object>
                 {
-                    {"txtContent", _txtContent.ClientID}, {"hidSize", _hidSize.ClientID}, {"keepSize", _keepSize},
+                    {"txtContent", _txtContent.ClientID}, {"hidSize", _hidSize?.ClientID ?? string.Empty}, {"keepSize", _keepSize},
                 };
                 StringBuilder sbCfg = new StringBuilder();
                 sbCfg.AppendFormat("<script>\n");
@@ -115,7 +115,7 @@ namespace VAR.WebFormsCore.Controls
             }
         }
 
-        private void CTextbox_PreRender(object sender, EventArgs e)
+        private void CTextbox_PreRender(object? sender, EventArgs e)
         {
             _txtContent.CssClass = CssClassBase;
             if (string.IsNullOrEmpty(_cssClassExtra) == false)
@@ -123,7 +123,7 @@ namespace VAR.WebFormsCore.Controls
                 _txtContent.CssClass = $"{CssClassBase} {_cssClassExtra}";
             }
 
-            if (Page.IsPostBack && (_allowEmpty == false && IsEmpty()) || _markedInvalid)
+            if (Page?.IsPostBack == true && (_allowEmpty == false && IsEmpty()) || _markedInvalid)
             {
                 _txtContent.CssClass += " textboxInvalid";
             }
@@ -154,10 +154,10 @@ namespace VAR.WebFormsCore.Controls
 
         public int? GetClientsideHeight()
         {
-            if (string.IsNullOrEmpty(_hidSize.Value)) { return null; }
+            if (string.IsNullOrEmpty(_hidSize?.Value)) { return null; }
 
             JsonParser jsonParser = new JsonParser();
-            Dictionary<string, object> sizeObj = jsonParser.Parse(_hidSize.Value) as Dictionary<string, object>;
+            Dictionary<string, object>? sizeObj = jsonParser.Parse(_hidSize.Value) as Dictionary<string, object>;
             if (sizeObj == null) { return null; }
 
             if (sizeObj.ContainsKey("height") == false) { return null; }
@@ -169,22 +169,28 @@ namespace VAR.WebFormsCore.Controls
         {
             if (height == null)
             {
-                _hidSize.Value = string.Empty;
+                if (_hidSize != null)
+                {
+                    _hidSize.Value = string.Empty;
+                }
                 return;
             }
 
-            Dictionary<string, object> sizeObj;
-            if (string.IsNullOrEmpty(_hidSize.Value) == false)
+            Dictionary<string, object?>? sizeObj = null;
+            if (string.IsNullOrEmpty(_hidSize?.Value) == false)
             {
                 JsonParser jsonParser = new JsonParser();
-                sizeObj = jsonParser.Parse(_hidSize.Value) as Dictionary<string, object>;
+                sizeObj = jsonParser.Parse(_hidSize.Value) as Dictionary<string, object?>;
             }
-            else
+            if(sizeObj == null)
             {
-                sizeObj = new Dictionary<string, object> {{"height", height}, {"width", null}, {"scrollTop", null},};
+                sizeObj = new Dictionary<string, object?> {{"height", height}, {"width", null}, {"scrollTop", null},};
             }
 
-            _hidSize.Value = JsonWriter.WriteObject(sizeObj);
+            if (_hidSize != null)
+            {
+                _hidSize.Value = JsonWriter.WriteObject(sizeObj);
+            }
         }
 
         #endregion Public methods
diff --git a/VAR.WebFormsCore/Controls/Control.cs b/VAR.WebFormsCore/Controls/Control.cs
index b7a46c3..f8c184b 100644
--- a/VAR.WebFormsCore/Controls/Control.cs
+++ b/VAR.WebFormsCore/Controls/Control.cs
@@ -9,7 +9,7 @@ namespace VAR.WebFormsCore.Controls
 {
     public class Control
     {
-        public event EventHandler PreInit;
+        public event EventHandler? PreInit;
 
         protected void OnPreInit(EventArgs e)
         {
@@ -17,8 +17,7 @@ namespace VAR.WebFormsCore.Controls
             foreach (Control control in Controls) { control.OnPreInit(e); }
         }
 
-
-        public event EventHandler Init;
+        public event EventHandler? Init;
 
         protected void OnInit(EventArgs e)
         {
@@ -27,7 +26,7 @@ namespace VAR.WebFormsCore.Controls
         }
 
 
-        public event EventHandler Load;
+        public event EventHandler? Load;
 
         protected virtual void Process() { }
 
@@ -38,7 +37,7 @@ namespace VAR.WebFormsCore.Controls
             foreach (Control control in Controls) { control.OnLoad(e); }
         }
 
-        public event EventHandler PreRender;
+        public event EventHandler? PreRender;
 
         protected void OnPreRender(EventArgs e)
         {
@@ -46,9 +45,9 @@ namespace VAR.WebFormsCore.Controls
             foreach (Control control in Controls) { control.OnPreRender(e); }
         }
 
-        private string _id;
+        private string? _id;
 
-        public string ID
+        public string? ID
         {
             get => _id;
             set
@@ -58,16 +57,16 @@ namespace VAR.WebFormsCore.Controls
             }
         }
 
-        private string _clientID;
+        private string? _clientID;
 
         public string ClientID
         {
             get { return _clientID ??= GenerateClientID(); }
         }
 
-        private Control _parent;
+        private Control? _parent;
 
-        public Control Parent
+        public Control? Parent
         {
             get => _parent;
             set
@@ -77,18 +76,18 @@ namespace VAR.WebFormsCore.Controls
             }
         }
 
-        private ControlCollection _controls;
+        private ControlCollection? _controls;
 
-        public string CssClass { get; set; }
+        public string CssClass { get; set; } = string.Empty;
 
         public ControlCollection Controls
         {
             get { return _controls ??= new ControlCollection(this); }
         }
 
-        private Page _page;
+        private Page? _page;
 
-        public Page Page
+        public Page? Page
         {
             get => _page;
             set
@@ -111,7 +110,7 @@ namespace VAR.WebFormsCore.Controls
                 sbClientID.Insert(0, currentID);
             }
 
-            Control parent = Parent;
+            Control? parent = Parent;
             while (parent != null)
             {
                 if (parent is INamingContainer)
@@ -131,9 +130,9 @@ namespace VAR.WebFormsCore.Controls
             return sbClientID.ToString();
         }
 
-        public Dictionary<string, string> Style { get; } = new Dictionary<string, string>();
+        public Dictionary<string, string> Style { get; } = new();
 
-        public Dictionary<string, string> Attributes { get; } = new Dictionary<string, string>();
+        public Dictionary<string, string> Attributes { get; } = new();
 
         public int Index { get; set; }
 
@@ -179,13 +178,19 @@ namespace VAR.WebFormsCore.Controls
             }
         }
 
-        protected List<Control> ChildsOfType<T>(List<Control> controls = null)
+        protected List<Control> ChildsOfType<T>(List<Control>? controls = null)
         {
             controls ??= new List<Control>();
 
             if (this is T) { controls.Add(this); }
 
-            foreach (Control child in _controls) { child.ChildsOfType<T>(controls); }
+            if (_controls != null)
+            {
+                foreach (Control child in _controls)
+                {
+                    child.ChildsOfType<T>(controls);
+                }
+            }
 
             return controls;
         }
diff --git a/VAR.WebFormsCore/Controls/HiddenField.cs b/VAR.WebFormsCore/Controls/HiddenField.cs
index 09cd9c8..9312d4d 100644
--- a/VAR.WebFormsCore/Controls/HiddenField.cs
+++ b/VAR.WebFormsCore/Controls/HiddenField.cs
@@ -14,9 +14,9 @@ namespace VAR.WebFormsCore.Controls
 
         protected override void Process()
         {
-            if (Page.IsPostBack && Page.Context.Request.Form.ContainsKey(ClientID))
+            if (Page?.IsPostBack == true && Page?.Context?.Request.Form.ContainsKey(ClientID) == true)
             {
-                Value = Page.Context.Request.Form[ClientID];
+                Value = Page?.Context.Request.Form[ClientID][0] ?? string.Empty;
             }
         }
 
diff --git a/VAR.WebFormsCore/Controls/HtmlForm.cs b/VAR.WebFormsCore/Controls/HtmlForm.cs
index 85dd8e0..a2668ce 100644
--- a/VAR.WebFormsCore/Controls/HtmlForm.cs
+++ b/VAR.WebFormsCore/Controls/HtmlForm.cs
@@ -26,16 +26,19 @@ namespace VAR.WebFormsCore.Controls
         private string GetAction()
         {
             StringBuilder sbAction = new();
-            sbAction.Append(Page.GetType().Name);
+            sbAction.Append(Page?.GetType().Name);
 
-            if (Page.Context.Request.Query.Count <= 0) { return sbAction.ToString(); }
+            if ((Page?.Context?.Request.Query.Count ?? 0) <= 0) { return sbAction.ToString(); }
 
             sbAction.Append('?');
-            foreach (KeyValuePair<string, StringValues> queryParam in Page.Context.Request.Query)
+            if (Page?.Context?.Request.Query != null)
             {
-                string key = ServerHelpers.UrlEncode(queryParam.Key);
-                string value = ServerHelpers.UrlEncode(queryParam.Value[0]);
-                sbAction.Append($"&{key}={value}");
+                foreach (KeyValuePair<string, StringValues> queryParam in Page.Context.Request.Query)
+                {
+                    string key = ServerHelpers.UrlEncode(queryParam.Key);
+                    string value = ServerHelpers.UrlEncode(queryParam.Value[0] ?? string.Empty);
+                    sbAction.Append($"&{key}={value}");
+                }
             }
 
             return sbAction.ToString();
diff --git a/VAR.WebFormsCore/Controls/HtmlHead.cs b/VAR.WebFormsCore/Controls/HtmlHead.cs
index 19923b2..6584b9f 100644
--- a/VAR.WebFormsCore/Controls/HtmlHead.cs
+++ b/VAR.WebFormsCore/Controls/HtmlHead.cs
@@ -4,7 +4,7 @@ namespace VAR.WebFormsCore.Controls
 {
     public class HtmlHead : Control
     {
-        public string Title { get; set; }
+        public string Title { get; set; } = string.Empty;
 
         protected override void Render(TextWriter textWriter)
         {
diff --git a/VAR.WebFormsCore/Controls/HtmlMeta.cs b/VAR.WebFormsCore/Controls/HtmlMeta.cs
index e4276fe..6ece7c9 100644
--- a/VAR.WebFormsCore/Controls/HtmlMeta.cs
+++ b/VAR.WebFormsCore/Controls/HtmlMeta.cs
@@ -4,9 +4,9 @@ namespace VAR.WebFormsCore.Controls
 {
     public class HtmlMeta : Control
     {
-        public string Name { get; init; }
-        public string Content { get; init; }
-        public string HttpEquiv { get; internal init; }
+        public string Name { get; init; } = string.Empty;
+        public string Content { get; init; } = string.Empty;
+        public string HttpEquiv { get; internal init; } = string.Empty;
 
         protected override void Render(TextWriter textWriter)
         {
diff --git a/VAR.WebFormsCore/Controls/HyperLink.cs b/VAR.WebFormsCore/Controls/HyperLink.cs
index 7708277..32dd616 100644
--- a/VAR.WebFormsCore/Controls/HyperLink.cs
+++ b/VAR.WebFormsCore/Controls/HyperLink.cs
@@ -4,8 +4,8 @@ namespace VAR.WebFormsCore.Controls
 {
     public class HyperLink : Control
     {
-        public string NavigateUrl { get; set; }
-        public string Text { get; init; }
+        public string NavigateUrl { get; set; } = string.Empty;
+        public string Text { get; init; } = string.Empty;
 
         protected override void Render(TextWriter textWriter)
         {
diff --git a/VAR.WebFormsCore/Controls/LiteralControl.cs b/VAR.WebFormsCore/Controls/LiteralControl.cs
index db5870d..da91318 100644
--- a/VAR.WebFormsCore/Controls/LiteralControl.cs
+++ b/VAR.WebFormsCore/Controls/LiteralControl.cs
@@ -4,7 +4,7 @@ namespace VAR.WebFormsCore.Controls
 {
     public class LiteralControl : Control
     {
-        public string Content { get; set; }
+        public string Content { get; set; } = string.Empty;
 
         public LiteralControl() { }
         public LiteralControl(string content) { Content = content; }
diff --git a/VAR.WebFormsCore/Controls/TextBox.cs b/VAR.WebFormsCore/Controls/TextBox.cs
index c1ea4e2..0ad9b43 100644
--- a/VAR.WebFormsCore/Controls/TextBox.cs
+++ b/VAR.WebFormsCore/Controls/TextBox.cs
@@ -11,9 +11,9 @@ namespace VAR.WebFormsCore.Controls
 
         protected override void Process()
         {
-            if (Page.IsPostBack && Page.Context.Request.Form.ContainsKey(ClientID))
+            if (Page?.IsPostBack == true && Page?.Context?.Request.Form.ContainsKey(ClientID) == true)
             {
-                Text = Page.Context.Request.Form[ClientID];
+                Text = Page?.Context.Request.Form[ClientID][0] ?? string.Empty;
             }
         }
 
diff --git a/VAR.WebFormsCore/Pages/FormUtils.cs b/VAR.WebFormsCore/Pages/FormUtils.cs
index 7fd7ed9..fb96a33 100644
--- a/VAR.WebFormsCore/Pages/FormUtils.cs
+++ b/VAR.WebFormsCore/Pages/FormUtils.cs
@@ -4,7 +4,7 @@ namespace VAR.WebFormsCore.Pages
 {
     public static class FormUtils
     {
-        public static Control CreatePanel(string cssClass, Control ctrl = null)
+        public static Control CreatePanel(string cssClass, Control? ctrl = null)
         {
             Panel pnl = new Panel();
             if (ctrl != null) { pnl.Controls.Add(ctrl); }
diff --git a/VAR.WebFormsCore/Pages/FrmError.cs b/VAR.WebFormsCore/Pages/FrmError.cs
index 66989dd..e89bf0e 100644
--- a/VAR.WebFormsCore/Pages/FrmError.cs
+++ b/VAR.WebFormsCore/Pages/FrmError.cs
@@ -21,7 +21,7 @@ namespace VAR.WebFormsCore.Pages
             Init += FrmError_Init;
         }
 
-        private void FrmError_Init(object sender, EventArgs e) { InitializeControls(); }
+        private void FrmError_Init(object? sender, EventArgs e) { InitializeControls(); }
 
         #endregion Page life cycle
 
@@ -34,7 +34,7 @@ namespace VAR.WebFormsCore.Pages
             Label lblErrorTitle = new Label {Text = Title, Tag = "h2"};
             Controls.Add(lblErrorTitle);
 
-            Exception exAux = _ex;
+            Exception? exAux = _ex;
             //if (exAux is HttpUnhandledException && exAux.InnerException != null) { exAux = exAux.InnerException; }
             while (exAux != null)
             {
diff --git a/VAR.WebFormsCore/Pages/Page.cs b/VAR.WebFormsCore/Pages/Page.cs
index 2075330..ec9ba6f 100644
--- a/VAR.WebFormsCore/Pages/Page.cs
+++ b/VAR.WebFormsCore/Pages/Page.cs
@@ -10,9 +10,9 @@ namespace VAR.WebFormsCore.Pages
 {
     public class Page : Control, IHttpHandler
     {
-        protected string Title { get; set; }
+        protected string Title { get; set; } = string.Empty;
 
-        public HttpContext Context { get; private set; }
+        public HttpContext? Context { get; private set; }
 
         private static readonly Encoding Utf8Encoding = new UTF8Encoding();
 
diff --git a/VAR.WebFormsCore/Pages/PageCommon.cs b/VAR.WebFormsCore/Pages/PageCommon.cs
index 1f03fee..5ffa2a6 100644
--- a/VAR.WebFormsCore/Pages/PageCommon.cs
+++ b/VAR.WebFormsCore/Pages/PageCommon.cs
@@ -9,12 +9,12 @@ namespace VAR.WebFormsCore.Pages
     {
         #region Declarations
 
-        private HtmlHead _head;
-        private HtmlBody _body;
-        private HtmlForm _form;
-        private readonly Panel _pnlContainer = new Panel();
-        private readonly Button _btnPostback = new Button();
-        private readonly Button _btnLogout = new Button();
+        private readonly HtmlHead _head = new();
+        private readonly HtmlBody _body = new();
+        private readonly HtmlForm _form = new() {ID = "formMain"};
+        private readonly Panel _pnlContainer = new();
+        private readonly Button _btnPostback = new();
+        private readonly Button _btnLogout = new();
 
         private bool _isAuthenticated;
 
@@ -37,20 +37,24 @@ namespace VAR.WebFormsCore.Pages
             PreRender += PageCommon_PreRender;
         }
 
-        private void PageCommon_PreInit(object sender, EventArgs e)
+        private void PageCommon_PreInit(object? sender, EventArgs e)
         {
-            Context.Response.PrepareUncacheableResponse();
+            Context?.Response.PrepareUncacheableResponse();
+
+            if (Context != null)
+            {
+                _isAuthenticated = GlobalConfig.Get().IsUserAuthenticated(Context);
+            }
 
-            _isAuthenticated = GlobalConfig.Get().IsUserAuthenticated(Context);
             if (MustBeAuthenticated && _isAuthenticated == false)
             {
-                Context.Response.Redirect(GlobalConfig.Get().LoginHandler);
+                Context?.Response.Redirect(GlobalConfig.Get().LoginHandler);
             }
         }
 
-        private void PageCommon_Init(object sender, EventArgs e) { CreateControls(); }
+        private void PageCommon_Init(object? sender, EventArgs e) { CreateControls(); }
 
-        private void PageCommon_PreRender(object sender, EventArgs e)
+        private void PageCommon_PreRender(object? sender, EventArgs e)
         {
             _head.Title = string.IsNullOrEmpty(Title)
                 ? GlobalConfig.Get().Title
@@ -62,10 +66,13 @@ namespace VAR.WebFormsCore.Pages
 
         #region UI Events
 
-        private void btnLogout_Click(object sender, EventArgs e)
+        private void btnLogout_Click(object? sender, EventArgs e)
         {
-            GlobalConfig.Get().UserUnauthenticate(Context);
-            if (MustBeAuthenticated) { Context.Response.Redirect(GlobalConfig.Get().LoginHandler); }
+            if(Context != null)
+            {
+                GlobalConfig.Get().UserUnauthenticate(Context);
+            }
+            if (MustBeAuthenticated) { Context?.Response.Redirect(GlobalConfig.Get().LoginHandler); }
         }
 
         #endregion UI Events
@@ -82,7 +89,6 @@ namespace VAR.WebFormsCore.Pages
             var html = new HtmlGenericControl("html");
             base.Controls.Add(html);
 
-            _head = new HtmlHead();
             html.Controls.Add(_head);
 
             _head.Controls.Add(new HtmlMeta {HttpEquiv = "X-UA-Compatible", Content = "IE=Edge"});
@@ -97,7 +103,7 @@ namespace VAR.WebFormsCore.Pages
                 }
             );
 
-            string version = Assembly.GetExecutingAssembly().GetName().Version?.ToString();
+            string? version = Assembly.GetExecutingAssembly().GetName().Version?.ToString();
             _head.Controls.Add(
                 new LiteralControl($"<script type=\"text/javascript\" src=\"ScriptsBundler?v={version}\"></script>\n")
             );
@@ -105,9 +111,7 @@ namespace VAR.WebFormsCore.Pages
                 new LiteralControl($"<link href=\"StylesBundler?v={version}\" type=\"text/css\" rel=\"stylesheet\"/>\n")
             );
 
-            _body = new HtmlBody();
             html.Controls.Add(_body);
-            _form = new HtmlForm {ID = "formMain"};
             _body.Controls.Add(_form);
 
             var pnlHeader = new Panel {CssClass = "divHeader"};
diff --git a/VAR.WebFormsCore/VAR.WebFormsCore.csproj b/VAR.WebFormsCore/VAR.WebFormsCore.csproj
index ee7f2fd..541ba73 100644
--- a/VAR.WebFormsCore/VAR.WebFormsCore.csproj
+++ b/VAR.WebFormsCore/VAR.WebFormsCore.csproj
@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Library</OutputType>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>