What is POCO in Entity Framework

POCO stands for "Plain Old CLR Object" Here CLR means Common Language Rutime that includes dotnet supported languages like C#, VB etc.

A Plain Old CLR Objects (POCO) is a class that doesn't depend on any framework-specific base class. It is like any other normal .Net class; that is why they are called “Plain Old CLR Objects”. These POCO entities support most of the same LINQ queries as Entity Object derived entities.

POCO allows you to write your own entity classes in a persistence ignorant fashion. POCO is also called as Persistence ignorant objects .

Persistence ignorance means that, as much as possible, anything in your code operating at the business logic layer or higher knows nothing about the actual design of the database, what database engine you're running, or how or when objects get retrieved from or persisted to the database. In the case of the EF, persistence ignorance is attained by working on POCO's and using LINQ to perform queries (i.e., not requiring the user to create any SQL queries to retrieve the desired objects).

There is still the need for you to “plug in” persistence and EF  so that your POCO entities can be take from the database and updated back to the database. In order to do this, you will still need to either create an Entity Data Model using the Entity Framework Designer

Joins in SQL

Joins in Structured Query Language (S Q L) are used to Store and Retrieve data from two or more Tables . Joins Store and Retrieve data On the basis of given Join Condition. The Given Join condition tells how and which data to retrieve / store in and from Database Tables.

Nopcommerce Developer Guide

Internship - Day 1

Today was first day of my internship Period of 6 months . I am very happy to start my internship with Abax Technologies . Abax technologies is a recognized IT company Situated in Noida . It deals with Desktop , web and Mobile application development and providing solutions to market .

Mr. Rohit Jain is CEO of Company and I am doing Internship under their guidance .

Now came to work -- On 2nd January - 8:23 am Rohit Sir posted my first task on skype . My first task was first to learn more about Nopcommerce , Its Architecture , Plugin development , Module Development , Theme development and widget development .

First i need to download the source code for Nopcommerce form Nopcommerce office webiste then using that source code to compile it , set up its database then run a demo site in nopcommerce .

After setup the demo site for nopcommerce it started exploring its source code architecture and learn more about it from its developer's documentation

I have previously done a ecommerce website in Nopcommerce but at that time i used Nopcommerce 1.9 version that was asp.net version of nopcommerce Now i am going to use Nopcommerce 3.2 and this version is really cool . It is MVC version of nopcommerce using Linq queries instead of using sql and using Razor view engines and more flexibility . Actually I liked this version .

Important Links that i have studied and explored today -

Link for Nopcommerce Developer's Documentation
Nopcommerce Developer Documentation

Nopcommerce uses code first approach for each and every development component in nopcommerce so i decided to first give a look at code first approach to revise my concepts about codefirst approach

Code First Approach Documentation MVC

After Reading about code first approach of Nopcommerce I reached a Nerd Dinner app that is MVC app that uses code first approch for MVC application development
Nerd Dinner MVC App with Code First Approach

So that was it for the day i learned number of things today

Today I have explored following Modules -

1. Nopcommerce Installation v3.20 (mvc)
2. Explored Nopcommerce Developers Documentation
3. Exploring Nopcommerce Architecture
4. Explored Nopcommerce Theme CUstomization and Creating Own Theme
5. Exploring Plugin Development Documentation
     -- Created simple hello world Plugin

Next I will explore create plugins with database access and various nopcommerce inbuilt modules

Datagridview Cellvaluechanged Event VB.net

DatagridView is a windows forms grid Control . It was first introduced in 

.Net framework 1.0 and It comes with advanced and improved features in .Net Framework 2.0  It allows you to show the data in the tabular form. It contains data organized in rows and columns. It can be used to retrieve data in Tabular from from Database . It can be bound to Sql Database or Microsoft-Access Database.

     

Datagridview Cellvaluechanged Event in VB.net is used to make the change to occur or to call an event when value within particular cell is changed. In this app I have put event on each . when value of cell is changed its corresponding value in Maskedtextbox will change


Download Datagridview cellvaluechanged App


Design For Datagridview Cellvaluechanged Event VB.net

-- Add DatagridView To Form

1. Click on Tools

2. Then Scroll down and Find Datagridview .





3. Now Double click on it to put it on windows form.



-- Add Columns To Datagridview

1. Single Click on Datagridview

2. Click on small arrow on Top-right of Datagridview

3. A pop-up Menu appears. Click on "Add Column"




4. Now in Add Column Dialog Box Change HeaderText to "Name" and Click on Add . This Adds column Name to Datagridview

5. Now in second column give HeaderText to "Salary"

6. Now in Third column give HeaderText to "Bonus"

7. Now in Fourth column give HeaderText to "Total Salary"

8. Now Add Four Labels to Form and change its text property to :-

( I ) Name
( II ) Salary
( III )Bonus
( IV )Total Salary

9. Take four Masked Textbox from Toolbox and drag them to Windows form





10. Take a Button and Change its Text Property to "Get Data".




How To Operate


1 click on Get Data Button

2. It will load Default data in datagridview

3. If you change data in any Datagridview column Then the corresponding value in MaskedTextbox also change

Code For Datagridview 

Cellvaluechanged Event vb.net App

Public Class Form5 Public isdirty As Boolean Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click DataGridView1.Rows(0).Cells(0).Value = "Jorge" DataGridView1.Rows(0).Cells(1).Value = 12000 DataGridView1.Rows(0).Cells(2).Value = 2900 DataGridView1.Rows(0).Cells(3).Value = DataGridView1.Rows(0).Cells(1).Value + DataGridView1.Rows(0).Cells(2).Value End Sub Private Sub MaskedTextBox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles MaskedTextBox1.TextChanged DataGridView1.Rows(0).Cells(0).Value = MaskedTextBox1.Text End Sub Private Sub MaskedTextBox2_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles MaskedTextBox2.TextChanged DataGridView1.Rows(0).Cells(1).Value = MaskedTextBox2.Text DataGridView1.Rows(0).Cells(3).Value = Val(DataGridView1.Rows(0).Cells(1).Value) + Val(DataGridView1.Rows(0).Cells(2).Value) End Sub Private Sub MaskedTextBox3_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MaskedTextBox3.TextChanged DataGridView1.Rows(0).Cells(2).Value = MaskedTextBox3.Text DataGridView1.Rows(0).Cells(3).Value = Val(DataGridView1.Rows(0).Cells(1).Value) + Val(DataGridView1.Rows(0).Cells(2).Value) End Sub Private Sub MaskedTextBox4_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MaskedTextBox4.TextChanged DataGridView1.Rows(0).Cells(3).Value = MaskedTextBox4.Text DataGridView1.Rows(0).Cells(3).Value = Val(DataGridView1.Rows(0).Cells(1).Value) + Val(DataGridView1.Rows(0).Cells(2).Value) End Sub Private Sub EndEdit(ByVal sender As System.Object, ByVal e As EventArgs) Handles DataGridView1.CurrentCellDirtyStateChanged If DataGridView1.IsCurrentCellDirty Then DataGridView1.CommitEdit(DataGridViewDataErrorContexts.Commit) End If End Sub Private Sub DataGridView1_TextChanged(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellValueChanged If e.RowIndex = -1 Then isdirty = True End If If e.ColumnIndex = 0 Then MaskedTextBox1.Text = DataGridView1.Rows(0).Cells(0).Value End If If e.ColumnIndex = 1 Then MaskedTextBox2.Text = DataGridView1.Rows(0).Cells(1).Value DataGridView1.Rows(0).Cells(3).Value = Val(DataGridView1.Rows(0).Cells(1).Value) + Val(DataGridView1.Rows(0).Cells(2).Value) End If If e.ColumnIndex = 2 Then MaskedTextBox3.Text = DataGridView1.Rows(0).Cells(2).Value DataGridView1.Rows(0).Cells(3).Value = Val(DataGridView1.Rows(0).Cells(1).Value) + Val(DataGridView1.Rows(0).Cells(2).Value) End If If e.ColumnIndex = 3 Then MaskedTextBox4.Text = DataGridView1.Rows(0).Cells(3).Value Dim c As Integer = DataGridView1.Rows(0).Cells(3).Value Dim str As String = CInt(c) If Len(str) = 1 Then MaskedTextBox4.Mask = "0" ElseIf Len(str) = 2 Then MaskedTextBox4.Mask = "00" ElseIf Len(str) = 3 Then MaskedTextBox4.Mask = "0,00" ElseIf Len(str) = 4 Then MaskedTextBox4.Mask = "0,000" ElseIf Len(str) = 5 Then MaskedTextBox4.Mask = "00,000" ElseIf Len(str) = 6 Then MaskedTextBox4.Mask = "0,00,000" ElseIf Len(str) = 7 Then MaskedTextBox4.Mask = "00,00,000" End If End If End Sub Private Sub Form5_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load MaskedTextBox4.Mask = "0000000" '' End Sub End Class

OUTPUT :-




After Changing value of Cell of Datagridview :-