LinQ Tutorial on DataTable – C#

Table of Contents

LinQ Tutorial

– This LINQ tutorial will show you some basic codes on implementing LINQ in C#.LINQ is an acronym for Language Integrated Query, which is descriptive for where it’s used and what it does. The Language Integrated part means that LINQ is part of programming language syntax. To have an overall view of the definition of LINQ please refer to this site I find csharp-station.com. Below are basic codes for implementing LINQ on a DataTable.

For more tutorial visit this link ASP.NET MVC Developement.

CopyToDataTable();

Note:

Employee -> DataTable Name

DataTable ToDataTable = (from emp in Employee.AsEnumerable()
                         select emp).CopyToDataTable();

Select All

Note:

Employee -> DataTable Name

var emp_selectAll = from emp in Employee.AsEnumerable()
select emp;

Select Specific column from DataTable

Note:

Name -> Table Column Name
Address -> Table Column Name
Employee -> DataTable Name

var emp_Select_column = from emp in Employee.AsEnumerable()
                               where emp.Field<string>("Name").Trim() == "name"
                               select new
                               {
                                   Name = emp.Field<string>("Name"), //variable
                                   LastName = emp.Field<string>("Address") //variable
                               };

Count()

Note:

Name -> Table Column Name
Address -> Table Column Name
Employee -> DataTable Name

       var emp_Select_Count = (from emp in Employee.AsEnumerable()
                               where emp.Field<string>("Name").Trim() == "name"
                               select new
                               {
                                   Name = emp.Field<string>("Name"), //variable
                                   LastName = emp.Field<string>("Address") //variable
                               }).Count();

Count();

Note:

Name -> Table Column Name
Employee -> DataTable Name
data -> Variable

 var Count = Employee.AsEnumerable().Count(data => data.Field<string>("Name") == "Jave");

ToList()

Note:

Name -> Table Column Name
Address -> Table Column Name

      var ToList = (from emp in Employee.AsEnumerable()
                               where emp.Field<string>("Name").Trim() == "name"
                               select new
                               {
                                   Name = emp.Field<string>("Name"),  //variable
                                   LastName = emp.Field<string>("Address") //variable
 
                               }).ToList();

SUM()

Note:

NUmberOfEmployee-> Table Column Name
data -> variable
Employee -> DataTable Name

    var Sum = Employee.AsEnumerable().Sum(data => data.Field<int>("NUmberOfEmployee"));

Group BY & order by

var data = dt.AsEnumerable() 
                                   .Where(a => DateTime.Parse(a.Field<string>("date")).Month == DateTime.Parse("01/01/2018").Month) 
                                   .GroupBy(x => new { dcount = x.Field<string>("ID") }) 
                                   .Select(group => new 
                                   { 
                                       x = group.Key.dcount, 
                                       Count = group.Count() 
                                   }) 
                                   .OrderByDescending(o => o.x);
var data = dt.AsEnumerable() 
                                   .Where(a => DateTime.Parse(a.Field<string>("date")).Month == DateTime.Parse("01/01/2018").Month) 
                                   .GroupBy(x => new { dcount = x.Field<string>("ID") }) 
                                   .Select(group => new 
                                   { 
                                       x = group.Key.dcount, 
                                       Count = group.Count() 
                                   }) 
                                   .OrderByDescending(o => o.x);