Practical Usage of Using ToLookup() Method in LINQ C#

//Iterates only string length having 9.
foreach (string temp in lookup[9])
{
HttpContext.Current.Response.Write(temp + "<br/>");
}
}

Step 5: Output of Simple Data Type



Step 6: Used Employee List for Demo

/// <summary>
/// Employee list
/// </summary>
public static List<Employee> EmployeeList()
{
List<Employee> emp = new List<Employee>();
emp.Add(new Employee { ID = 100, Name = "Lajapathy", CompanyName = "FE" });
emp.Add(new Employee { ID = 200, Name = "Parthiban", CompanyName = "FE" });
emp.Add(new Employee { ID = 400, Name = "Sathiya", CompanyName = "FE" });
emp.Add(new Employee { ID = 300, Name = "Anand Babu", CompanyName = "FE" });
emp.Add(new Employee { ID = 300, Name = "Naveen", CompanyName = "HCL" });
return emp;
}

Step 7: Code Snippet using Complex Data Type (Object)

public static void AdvaceLookupLookup()
{
//Employee collection
List<Employee> empList = EmployeeList();
HttpContext.Current.Response.Write("Here Key based on ID<br/>");

//Creating KeyValue pair based on the ID. we can get items based on the ID.
ILookup<int, Employee> lookList = empList.ToLookup(id => id.ID);

//Displaying who having the ID=100.
foreach (Employee temp in lookList[100])
{
HttpContext.Current.Response.Write(temp.Name + "<br/>");
}
HttpContext.Current.Response.Write("Here Key based on CompanyName<br/>");

//Creating KeyValue pair based on the CompanyName.
//we can get items based on the CompanyName.
ILookup<string, Employee> lookList2 = empList.ToLookup(id => id.CompanyName);

//Displaying who are employed in CompanyName=FE.
foreach (Employee temp in lookList2["FE"])
{
HttpContext.Current.Response.Write(temp.Name + "<br/>");
}
}

Step 8: Output of Complex Data Type



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