diff --git a/modern-c++/README.md b/modern-c++/README.md
new file mode 100644
index 0000000..49fb2e4
--- /dev/null
+++ b/modern-c++/README.md
@@ -0,0 +1,47 @@
+# Guide to modern C++
+
+- Essentials of Modern C++ Style [CppCon 2014](https://www.youtube.com/watch?v=xnqTKD8uD64&t=2304s)
+
+- [Style Guides](https://lefticus.gitbooks.io/cpp-best-practices/content/03-Style.html)
+
+- [Herb Stutter's style](https://herbsutter.com/elements-of-modern-c-style/)
+- [Bjarne Stroustrup's C++ Style](https://www.stroustrup.com/bs_faq2.html)
+
+## C++20
+- Error : 
+  - C2664 - cannot convert ... 'const[4] to char*'
+  - C2132 expression didnot evalute to a constant
+```C++
+void myFn(char* data)
+{
+    std::cout << data;
+    return;
+}
+
+int main()
+{
+    myFn("ABC");  ==> error
+    myFn(const_cast<char*>("ABC"));  ==> OK
+    std::cout << "Hello World!\n";
+}
+
+constexpr struct stIniEnumToFilenameMap LogNameMap[] =
+{
+    {CFileLocation::DEBUG_LOG,        const_cast<TCHAR*>("Dbg.log")},
+    {CFileLocation::DEBUG_TIMING_LOG, const_cast<TCHAR*>("DbgTiming.log"},
+    {CFileLocation::GUIEVENT_LOG,     const_cast<TCHAR*>("GUIEventLog.log"},
+};
+```
+
+- range for loop `for each()`
+```C++
+
+for each (auto x in items){}  ==> error
+
+for (auto x : items) {} ==> OK
+```
+
+- Error: C2440	'initializing': cannot convert from 'ATL::CA2CA' to 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>'
+```C++
+std::string strModelName = hardwareIniMotionCard.GetString(osKey.str().c_str(), "Error", FALSE).GetString();  ==> OK - use CString().GetString()
+```
diff --git a/visualstudio/README.md b/visualstudio/README.md
new file mode 100644
index 0000000..3f81bb7
--- /dev/null
+++ b/visualstudio/README.md
@@ -0,0 +1,4 @@
+# Visual Studio Information
+
+- [Troubleshooting](TroubleshootingGuide.md)
+- []
diff --git a/visualstudio/TroubleshootingGuide.md b/visualstudio/TroubleshootingGuide.md
new file mode 100644
index 0000000..87a5cfa
--- /dev/null
+++ b/visualstudio/TroubleshootingGuide.md
@@ -0,0 +1,19 @@
+# Issues
+
+## heap debug error 
+- Symptom : Calling DLL function with std::string parameter / return value, causing heap debug error upon return
+- Cause: The caller DLL must compile using the same `[Code Generation]` - `[Runtime Library]` flag. eg: `/MDd` Multi-threaded Debug DLL
+- Remedy: Update the flag accordingly
+
+## Compile erro on Simple console project consuming MFC related DLL
+- Symptom : Compile Error C1189: #error : Building MFC application with /MD[d] (CRT dll version) requires MFC shared dll version. Please #define _AFXDLL or do not use /MD[d]
+- Cause : Default console project for `Advance`->`Use of MFC` is `Use Standard Windows Libraries`
+- Remedy: Switch setting to `Use MFC in a Shared DLL`
+
+## Compile error for string parameters
+- Symptom: Unable to match LPCSTR parameters / arguments
+- Cause: `Advanced`->`Character Set` Setting mismatch. Default VS2022 project is using `Unicode Character set`.
+- Remedy: Change to `Multi-byte Character Set` if original DLL is using MBCS Character Set
+
+## Database open fail on 64-bit (C#)
+- Symptom: 
\ No newline at end of file
diff --git a/visualstudio/entityFramework.md b/visualstudio/entityFramework.md
new file mode 100644
index 0000000..783a503
--- /dev/null
+++ b/visualstudio/entityFramework.md
@@ -0,0 +1,75 @@
+# Entity Framework Core
+
+- As of 2022, mdb entity ONLY support EF Core 3.x
+- [EntityFrameworkCore.Jet](https://github.com/bubibubi/EntityFrameworkCore.Jet)
+- [Tutorial](https://www.entityframeworktutorial.net/efcore/entity-framework-core.aspx)
+- [EF Core best practice (Youtube)](https://www.youtube.com/watch?v=qkJ9keBmQWo&t=7122s)
+
+## Code First Approach
+- Create the code for DbContext and models
+- Run the migration script to generate the db tables
+- [Tutorial](https://www.yogihosting.com/code-first-entity-framework-core/)
+
+```PM
+PM> add-migration InitialDb
+PM> update-database
+PM> remove-migration
+PM> Drop-Database
+PM> script-migration
+```
+
+## Database First Approach (Reverse Engineering)
+- Note: For mdb, this only work with Jet.OleDB Provider
+- Generate DbContext & model from database
+- [Tutorial] (https://github-wiki-see.page/m/bubibubi/EntityFrameworkCore.Jet/wiki/Using-Entity-Framework-Core-with-Jet-in-Traditional-.Net-Applications)
+- Nuget package
+  - Microsoft.EntityFrameworkCore (3.1.31)
+  - EntityFrameworkCore.Jet.OleDb (3.1.1)
+  - Microsoft.EntityFrameworkCore.Tools (3.1.31)
+
+```PM
+PM> Scaffold-DbContext "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\myFolder\MitLanguage.mdb;" EntityFrameworkCore.Jet -OutputDir Models -DataAnnotations -Force
+
+```
+
+## Connection String
+- [ConnectionString](https://www.connectionstrings.com/)
+
+- Using OleDb (EntityFrameworkCore.Jet.OleDb)
+  - x64 : `Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\myFolder\\MitLanguage.mdb;`
+  - x86 : `Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\\Machine\\Database\\MitMc.mdb;`
+
+- Using ODBC (EntityFrameworkCore.Jet.Odbc)
+  - x64 : `Driver={Microsoft Access Driver (*.mdb, *.accdb)}; Dbq = C:\\myFolder\\MitCustom.mdb; Exclusive=1; Uid = Admin; Pwd =;`
+  - x86 : `Driver={Microsoft Access Driver (*.mdb)}; Dbq = C:\\myFolder\\MitCustom.mdb; Exclusive=1; Uid = Admin; Pwd =;`
+  - For x86, use `ODBC Data Source (32-bit)` to add the UserDSN driver for 32-bit platform
+
+## Sample Query
+
+```C#
+using EFCoreTest.Models;
+using System.Text.Json;
+
+using (var db = new CustomContext())
+{
+    ReelAutoChanger? reelAutoChanger = db.ReelAutoChanger.FirstOrDefault();
+    string jsonString = JsonSerializer.Serialize(reelAutoChanger);
+    Console.WriteLine(jsonString);
+    Console.ReadKey();
+}
+
+using (var db = new MachineContext())
+{
+    List<MotorProfile> motorProfiles = db.MotorProfile.ToList();
+    //IQueryable<MotorProfile> motorProfiles = db.MotorProfile.FromSqlRaw("Select * from MotorProfile");
+    //var emp = context.Employee.FromSqlRaw("Select * from Employee").OrderBy(x => x.Name).ToList();
+    string jsonString = JsonSerializer.Serialize(motorProfiles);
+    Console.WriteLine(jsonString);
+    Console.ReadKey();
+
+    List<Motor> motors = db.Motor.Where(b => b.ModuleName == "PnP").ToList();
+    jsonString = JsonSerializer.Serialize(motors);
+    Console.WriteLine(jsonString);
+    Console.ReadKey();
+}
+```
\ No newline at end of file