Following tutorial from Gavin Lon
Link: https://www.youtube.com/playlist?list=PL4LFuHwItvKbzDl6MBp3XY0MrnALSfyub

Part 1 - Introduction

Project related to this

• TCPData
• TCPExtension
• ThePretendCommpanyApplication

Some summary

• Class extension and Lambda expression
• IEnumerable and IQueryable
• Create class extension filter and try it to filter list of Employee and Department
• Use already defined extension in Linq, Where
• sql-like query syntax provided by Linq, but some query still need to use extension method provided by Linq

Part 2 - Queries

Project related to this

• LINQExamples_1

Some summary

• Method Syntax and Query Syntax
• Select method syntax

  var results = employeeList.Select(e => new
          {
              FullName = e.FirstName + " " + e.LastName,
              AnnualSalary = e.AnnualSalary
          });
  
  
  // with chaining
  var results = employeeList.Select(e => new
          {
              FullName = e.FirstName + " " + e.LastName,
              AnnualSalary = e.AnnualSalary
          }).Where(e => e.AnnualSalary >= 50000);
  
  
  

• Select Query Syntax

  var results = from emp in employeeList
            select new
            {
                FullName = emp.FirstName + " " + emp.LastName,
                AnnualSalary = emp.AnnualSalary
            };
  
  
  // with where clause
  var results = from emp in employeeList
            where emp.AnnualSalary >=50000
            select new
            {
                FullName = emp.FirstName + " " + emp.LastName,
                AnnualSalary = emp.AnnualSalary
            };
  

• Deffered and Immediate Execution
  Immediate execution with "To conversion method"
• INNER JOIN using operator JOIN Method Syntax

  var results = departmentList.Join(employeeList,
  department => department.Id,
  employee => employee.DepartmentId,
  (department, Employee) => new
  {
      FullName = Employee.FirstName + " " + Employee.LastName,
      AnnualSalary = Employee.AnnualSalary,
      departmentName = department.Longname
  });
  

• INNER JOIN using query syntax

  var results = from dept in departmentList
            join emp in employeeList
            on dept.Id equals emp.DepartmentId
            select new
            {
                FullName = emp.FirstName + " " + emp.LastName,
                AnnualSalary = emp.AnnualSalary,
                departmentName = dept.Longname
            };
  

• LEFT OUTER JOIN using GroupJoin operator

  var results = departmentList.GroupJoin(employeeList,
  dep => dep.Id,
  emp => emp.DepartmentId,
  (dept, employeesGroup) => new
  {
      Employees = employeesGroup,
      DepartmentName = dept.Longname
  });
  

• LEFT OUTER JOIN using into keyword and join

  var results = from dept in departmentList
            join emp in employeeList
            on dept.Id equals emp.DepartmentId
            into employeeGroup
            select new
            {
                Employees = employeeGroup,
                DepartmentName = dept.Longname
            };