Working or consuming three tier/Layered architecture .Net windows application

 How to communicate or work in 3-layered architecture in C#.Net Windows Application

Introduction:

In my previous articles i explained the WPF Architecture, How to create 3-tier architecture in C#.Net Windows Application,Now in this Example you will know how to consume or how to work with 3 layered architecture in C#.Net Applications.

Description:

After creating three tier architecture to work with this we  have to add references between these three layers. The communication between these three layers is as follows

3-tier Architecture layers communication

For any Db operations like select,insert,delete,update the request processing is as show in above image.

Suppose if you are performing select operation you called a method in business access layer from presentation layer(Form). In business access layer if you need to perform any validations then you can do there and then call the method in data access layer which will communicate with database and process your request and returns the result back to business access layer.  From Business Access Layer data is returned to called method in .cs file or .vb file.

Here i will explain the communication between three tier architecture with an example. Form looks likes this

This form level coding i.e .cs file coding which i had written is as follows

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Data.SqlClient; using System.IO; namespace Presentation_Layer { public partial class Register : Form { public Register() { InitializeComponent(); } SqlConnection con; SqlCommand cmd; SqlDataAdapter da; DataSet ds; int rno=0; byte[] data; string imgPath; Business_Access_Layer.Class1 ObjBlClass1 = new Business_Access_Layer.Class1(); private void Form11_Load(object sender, EventArgs e) { btnPrev.Enabled = false; btnNext.Enabled = false; } private void btnLoad_Click(object sender, EventArgs e) { openFileDialog1.ShowDialog(); imgPath = openFileDialog1.FileName; pictureBox1.ImageLocation = imgPath; } private void btnClear_Click(object sender, EventArgs e) { textBox1.Text = textBox2.Text = textBox3.Text = textBox4.Text = ""; pictureBox1.Image = null; textBox1.Focus(); btnPrev.Enabled = false; btnNext.Enabled = true; } private void ShowData() { try { if (ds.Tables[0].Rows.Count > 0) { textBox1.Text = ds.Tables[0].Rows[rno][0].ToString(); textBox2.Text = ds.Tables[0].Rows[rno][1].ToString(); textBox3.Text = ds.Tables[0].Rows[rno][2].ToString(); textBox4.Text = ds.Tables[0].Rows[rno][3].ToString(); //Code for converting byte[] back into a Image if (ds.Tables[0].Rows[rno][4] != DBNull.Value) { data = (byte[])ds.Tables[0].Rows[rno][4]; MemoryStream ms = new MemoryStream(data); pictureBox1.Image = Image.FromStream(ms); } else pictureBox1.Image = null; } } catch (Exception ex) { MessageBox.Show(ex.Message, "error occured while fetching record"); } } private void btnInsert_Click(object sender, EventArgs e) { try { //Code for converting image into byte[] data = File.ReadAllBytes(imgPath); ObjBlClass1.InsertOrUpdateEmployee(textBox1.Text.Trim(), textBox2.Text.Trim(), textBox3.Text.Trim(), textBox4.Text.Trim(), data); MessageBox.Show(textBox2.Text.Trim()+" employee is successfully added."); } catch (Exception ex) { MessageBox.Show(ex.Message,"error occured while inserting record"); } } private void btnUpdate_Click(object sender, EventArgs e) { btnInsert.PerformClick(); } private void btnDelete_Click(object sender, EventArgs e) { try { ObjBlClass1.DeleteEmployee(textBox1.Text); MessageBox.Show("Employee is deleted Successfully"); btnClear.PerformClick(); } catch (Exception ex) { MessageBox.Show(ex.Message,"Error Occured while Deleting Employee"); } finally { } } private void btnClose_Click(object sender, EventArgs e) { this.Close(); } private void btnLoadData_Click(object sender, EventArgs e) { try { rno = 0; ds = new DataSet(); ds = ObjBlClass1.GetAllEmployees(); ShowData(); btnNext.Enabled = true; btnPrev.Enabled = false; } catch (Exception ex) { MessageBox.Show(ex.Message, "Error Occured while loading Employees"); } } private void btnPrev_Click(object sender, EventArgs e) { try { if (rno > 0) { rno--; } ShowData(); if (rno == 0) { btnPrev.Enabled = false; btnNext.Enabled = true; } else { btnPrev.Enabled = true; btnNext.Enabled = true; } } catch(Exception ex) { } } private void btnNext_Click(object sender, EventArgs e) { try { if (rno < ds.Tables[0].Rows.Count-1) { rno++; } ShowData(); if (rno == ds.Tables[0].Rows.Count-1) { btnNext.Enabled = false; btnPrev.Enabled = true; } else { btnNext.Enabled = true; btnPrev.Enabled = true; } } catch (Exception ex) { } } } }

I have written business access layer coding for this form is as follows

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; namespace Business_Access_Layer { public class Class1 { Data_Access_Layer.Class1 ObjDlClass1 = new Data_Access_Layer.Class1(); public DataSet GetAllEmployees() { DataSet ds=new DataSet(); try { ds = ObjDlClass1.LoadEmployeeData(); } catch (Exception ex) { throw ex; } return ds; } public void InsertOrUpdateEmployee(string EmpNumber,string Ename,string job,string Salary,byte[] photo) { try { ObjDlClass1.InsertOrUpdateEmployee(Convert.ToInt32(EmpNumber), Ename, job, Convert.ToDouble(Salary), photo);// converting employee number string to integer } catch (Exception ex) { throw ex; } } public void DeleteEmployee(string EmpNumber) { try { //Perform validations Convert string to integer type ObjDlClass1.DeleteEmployee(Convert.ToInt32(EmpNumber)); } catch (Exception ex) { throw ex; } } } }

Data access layer coding for this form is as follows

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data.SqlClient; using System.Data; namespace Data_Access_Layer { public class Class1 { SqlConnection con; SqlCommand cmd; SqlDataAdapter da; public DataSet LoadEmployeeData() { DataSet ds = new DataSet(); try { con =new SqlConnection("User Id=Sa; Password=9290812112; Database=CS9DB"); cmd = new SqlCommand(); cmd.Connection = con; cmd.CommandType = CommandType.StoredProcedure; cmd.CommandText = "Usp_Get_AllEmployees"; da = new SqlDataAdapter(cmd); ds = new DataSet(); da.Fill(ds, "Employee"); } catch (Exception ex) { throw ex; } finally { con.Close(); } return ds; } public void InsertOrUpdateEmployee(int EmpNumber, string Ename, string job, double Salary, byte[] photo) { try { con = new SqlConnection("User Id=Sa; Password=9290812112; Database=CS9DB"); cmd = new SqlCommand(); cmd.Connection = con; cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.Clear(); cmd.CommandText = "Employee_InsertOrUpdate"; cmd.Parameters.AddWithValue("@Eno", EmpNumber); cmd.Parameters.AddWithValue("@Ename", Ename); cmd.Parameters.AddWithValue("@Job", job); cmd.Parameters.AddWithValue("@Salary", Salary); cmd.Parameters.AddWithValue("@Photo", photo); con.Open(); cmd.ExecuteNonQuery(); } catch (Exception ex) { throw ex; } finally { con.Close(); } } public void DeleteEmployee(int EmpNumber) { try { con = new SqlConnection("User Id=Sa; Password=9290812112; Database=CS9DB"); cmd = new SqlCommand(); cmd.Connection = con; cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.Clear(); cmd.CommandText = "Employee_Delete"; cmd.Parameters.AddWithValue("@Eno", EmpNumber); con.Open(); cmd.ExecuteNonQuery(); } catch (Exception ex) { throw ex; } finally { con.Close(); } } } }

Observe the method calling between three layers you will get flow.

Download Here:

Aspdotnet-sekhar's Working or consuming 3 - tier architeture in .Net Windows Application 

Download Database for this Application

To work with this download Visual Studio Solution and Database Backup from Above two links and add database backup file to Your system and change the db connection string, Db name is CS9DB.

Observe the flow of input values and output values how they are inputted and outputted Business layers and data access layers.
 

Conclusion

I hope you got an idea how to work with 3 layered architecture of .Net Application. In my next article i will explain communication between three layered architecture web application i.e using Asp.Net.

         I would like to have feedback from my blog readers. Your valuable feedback,Suggestions,Questions, Comments about this article are always welcome.

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