KishoR NaiK: LINQ - Linq to Object Part 6 Join

Linq to Object Part 5

Joins are the most important function of SQL Operators. Linq supports join operations using the join operator. The join operator performs an inner join of two collections based on matching keys extracted from the elements.

Let See how to create a Join.

Step 1
Create a web application and give the solution name as SolLinqJoin.

Step 2
Add a gridview in page,it is look like this

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:GridView ID="GvStudent" runat="server" BackColor="White" 
            BorderColor="#999999" BorderStyle="Solid" BorderWidth="1px" CellPadding="3" 
            EnableModelValidation="True" ForeColor="Black" GridLines="Vertical">
            <AlternatingRowStyle BackColor="#CCCCCC" />
            <FooterStyle BackColor="#CCCCCC" />
            <HeaderStyle BackColor="Black" Font-Bold="True" ForeColor="White" />
            <PagerStyle BackColor="#999999" ForeColor="Black" HorizontalAlign="Center" />
            <SelectedRowStyle BackColor="#000099" Font-Bold="True" ForeColor="White" />
        </asp:GridView>  
    </div>
    </form>
</body>
</html>

Step 3
Create a Division class in App_Code folder,it is look like this

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

/// <summary>
///  Add the Division Data
/// </summary>
public class Division
{
    #region Property

    public int DivID
    {
        get;
        set;
    }
    public String DivName
    {
        get;
        set;
    }

    #endregion
}

Step 4
Create a Student class in App_Code folder,it is look like this

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

/// <summary>
/// Add a Student Data
/// </summary>
public class Student
{
    #region Property

    public int StudentID
    {
        get;
        set;
    }

    public String Name
    {
        get;
        set;
    }

    public int DivID
    {
        get;
        set;
    }


    #endregion
}

Step 5
Create a method for add division and student data in default.cs class,it is look like this

 /// <summary>
    /// Add the Division Data
    /// </summary>
    /// <returns>List</returns>
    private List<Division> AddDivisionData()
    {
        try
        {
            Division Div1 = new Division();
            Div1.DivID = 1;
            Div1.DivName = "A";

            Division Div2 = new Division();
            Div2.DivID = 2;
            Div2.DivName = "B";

            Division Div3 = new Division();
            Div3.DivID=3;
            Div3.DivName="C";

            List<Division> ListDiv = new List<Division>();
            ListDiv.Add(Div1);
            ListDiv.Add(Div2);
            ListDiv.Add(Div3);

            return ListDiv; 
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);  
        }
    }

    /// <summary>
    /// Add the Student Data
    /// </summary>
    /// <returns>List</returns>
    private List<Student> AddStudentData()
    {
        try
        {
            Student Std1 = new Student();
            Std1.StudentID = 1;  
            Std1.Name = "Kishor";
            Std1.DivID = 1;

            Student Std2 = new Student();
            Std2.StudentID = 2;  
            Std2.Name = "Kakashi";
            Std2.DivID = 1;  

            Student Std3 = new Student();
            Std3.StudentID = 3;  
            Std3.Name = "Lee";
            Std3.DivID  = 2;

            Student Std4 = new Student();
            Std4.StudentID = 4;
            Std4.Name = "Ramdas";
            Std4.DivID = 1;

            Student Std5 = new Student();
            Std5.StudentID = 5;
            Std5.Name = "Jhon";
            Std5.DivID = 2;

            Student Std6 = new Student();
            Std6.StudentID = 6;
            Std6.Name = "Jiraiya";
            Std6.DivID = 3;
           

            Student Std7 = new Student();
            Std7.StudentID = 7;
            Std7.Name = "shikamaro";
            Std7.DivID = 3;

            Student Std8 = new Student();
            Std8.StudentID = 8;
            Std8.Name = "Eun-ju";
            Std8.DivID = 1;

            Student Std9 = new Student();
            Std9.StudentID = 9;
            Std9.Name = "Naruto";
            Std9.DivID = 3;

            Student Std10 = new Student();
            Std10.StudentID = 10;
            Std10.Name = "David";
            Std10.DivID = 2;

            Student Std11 = new Student();
            Std11.StudentID = 11;
            Std11.Name = "Sakura";
            Std11.DivID = 2;
            

            List<Student> StudentObj = new List<Student>();
            StudentObj.Add(Std1);
            StudentObj.Add(Std2);
            StudentObj.Add(Std3);
            StudentObj.Add(Std4);
            StudentObj.Add(Std5);
            StudentObj.Add(Std6);
            StudentObj.Add(Std7);
            StudentObj.Add(Std8);
            StudentObj.Add(Std9);
            StudentObj.Add(Std10);
            StudentObj.Add(Std11);
           

            return StudentObj; 

        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);  
        }
    }

Step 6
Perform join operation,it is look like this

  /// <summary>
    /// Perform join operation and display data in gridview
    /// </summary>
    /// <param name="ListDiv"></param>
    /// <param name="ListStudent"></param>
    private void Join(List<Division>ListDiv,List<Student>ListStudent)
    {
        try
        {
            /// get Division Data
            var DivQuery = from D in ListDiv
                           select D;

            /// Get Student Data
            var StudentQuery = from S in ListStudent
                               select S;

            /// Join Process

            var JoinQuery = from D in DivQuery
                                    join
                                        S in StudentQuery
                                    on
                                        D.DivID equals S.DivID
                                        orderby S.StudentID ascending 
                                    select new
                                    {
                                        StudentID=S.StudentID,
                                        Name=S.Name,
                                        Division=D.DivName 
                                    };

            /// Bind the Data in GridView
            GvStudent.DataSource = JoinQuery;
            GvStudent.DataBind();  
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message); 
        }
    }

Step 7

Call a Join method in Page_Load event, it is look like this

 protected void Page_Load(object sender, EventArgs e)
    {
        try
        {
            if (IsPostBack == false)
            {
                Join(AddDivisionData(), AddStudentData());   
            }
        }
        catch (Exception)
        { }
    }

Full .aspx.cs Code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {
        try
        {
            if (IsPostBack == false)
            {
                Join(AddDivisionData(), AddStudentData());   
            }
        }
        catch (Exception)
        { }
    }

    #region Methods
    /// <summary>
    /// Add the Division Data
    /// </summary>
    /// <returns>List</returns>
    private List<Division> AddDivisionData()
    {
        try
        {
            Division Div1 = new Division();
            Div1.DivID = 1;
            Div1.DivName = "A";

            Division Div2 = new Division();
            Div2.DivID = 2;
            Div2.DivName = "B";

            Division Div3 = new Division();
            Div3.DivID=3;
            Div3.DivName="C";

            List<Division> ListDiv = new List<Division>();
            ListDiv.Add(Div1);
            ListDiv.Add(Div2);
            ListDiv.Add(Div3);

            return ListDiv; 
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);  
        }
    }

    /// <summary>
    /// Add the Student Data
    /// </summary>
    /// <returns>List</returns>
    private List<Student> AddStudentData()
    {
        try
        {
            Student Std1 = new Student();
            Std1.StudentID = 1;  
            Std1.Name = "Kishor";
            Std1.DivID = 1;

            Student Std2 = new Student();
            Std2.StudentID = 2;  
            Std2.Name = "Kakashi";
            Std2.DivID = 1;  

            Student Std3 = new Student();
            Std3.StudentID = 3;  
            Std3.Name = "Lee";
            Std3.DivID  = 2;

            Student Std4 = new Student();
            Std4.StudentID = 4;
            Std4.Name = "Ramdas";
            Std4.DivID = 1;

            Student Std5 = new Student();
            Std5.StudentID = 5;
            Std5.Name = "Jhon";
            Std5.DivID = 2;

            Student Std6 = new Student();
            Std6.StudentID = 6;
            Std6.Name = "Jiraiya";
            Std6.DivID = 3;
           

            Student Std7 = new Student();
            Std7.StudentID = 7;
            Std7.Name = "shikamaro";
            Std7.DivID = 3;

            Student Std8 = new Student();
            Std8.StudentID = 8;
            Std8.Name = "Eun-ju";
            Std8.DivID = 1;

            Student Std9 = new Student();
            Std9.StudentID = 9;
            Std9.Name = "Naruto";
            Std9.DivID = 3;

            Student Std10 = new Student();
            Std10.StudentID = 10;
            Std10.Name = "David";
            Std10.DivID = 2;

            Student Std11 = new Student();
            Std11.StudentID = 11;
            Std11.Name = "Sakura";
            Std11.DivID = 2;
            

            List<Student> StudentObj = new List<Student>();
            StudentObj.Add(Std1);
            StudentObj.Add(Std2);
            StudentObj.Add(Std3);
            StudentObj.Add(Std4);
            StudentObj.Add(Std5);
            StudentObj.Add(Std6);
            StudentObj.Add(Std7);
            StudentObj.Add(Std8);
            StudentObj.Add(Std9);
            StudentObj.Add(Std10);
            StudentObj.Add(Std11);
           

            return StudentObj; 

        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);  
        }
    }

    /// <summary>
    /// Perform join operation and display data in gridview
    /// </summary>
    /// <param name="ListDiv"></param>
    /// <param name="ListStudent"></param>
    private void Join(List<Division>ListDiv,List<Student>ListStudent)
    {
        try
        {
            /// get Division Data
            var DivQuery = from D in ListDiv
                           select D;

            /// Get Student Data
            var StudentQuery = from S in ListStudent
                               select S;

            /// Join Process

            var JoinQuery = from D in DivQuery
                                    join
                                        S in StudentQuery
                                    on
                                        D.DivID equals S.DivID
                                        orderby S.StudentID ascending 
                                    select new
                                    {
                                        StudentID=S.StudentID,
                                        Name=S.Name,
                                        Division=D.DivName 
                                    };

            /// Bind the Data in GridView
            GvStudent.DataSource = JoinQuery;
            GvStudent.DataBind();  
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message); 
        }
    }

    #endregion
}

Run the project.

Download
Download Source Code

Linq to Object Part 5

KishoR NaiK

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Sunday, September 19, 2010

LINQ - Linq to Object Part 6 Join

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