Unable to update the EntitySet 'TableName' because it has a DefiningQuery and no element exists in the element to support the current operation.

Table don't have a primary key.. add primary and update edmx..

unable to check out the current file. the file may be read only or locked

 Goto tools > Options > Source Control > Current source control  plug- in select None and try to add service Or project run in admin mode and add.. it will work

Foreach entity framework query

 employee.ForEach(em=>
                    {
                        em.sal= (em.sal !=null ?em.sal:0);
                    });

How to Count Total Number of HIT in Asp.net MVC?

 Applicatin_start()

 Application.Lock();  

Application["Totaluser"] = (int)Application["Totaluser"] + 1;        

Application.UnLock(); 

How to add zeros after decimal point

 var a= 10.1;

var result  = a.ToString("f2");

result = 10.10;

Cannot drop database "abc" because it is currently in use.

We will face the problem:

USE TEstDb; DROP DATABASE TEstDb;

Solution:

 Use Master

DROP DATABASE TEstDb

Reading Excel From C# using OLEDB Connection

 First, You need to add below name spaces to read Excel file in OLEDB

using System.Data.OleDb;

using System.Configuration;

using System.Data.SqlClient;

And we need establish a connection to the Database and OLEDB. Add below connection code in web.config file

<connectionStrings>

   <add name="AD_Phase2" connectionString="Data Source=localhost;Database=DatabaseName;User Id=sa;Password=Password" providerName="System.Data.SqlClient"/>

    <add name="ExcelConnection" connectionString="Provider=Microsoft.ACE.OLEDB.12.0;Extended Properties='Excel 12.0;HDR=NO'\"/>

    <add name="Excel03ConString" connectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source={0};Extended Properties='Excel 8.0;HDR=NO'"/>

    <add name="Excel07ConString" connectionString="Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties='Excel 12.0;HDR=NO'"/>

  </connectionStrings>

Below is the code for read the Excel data and fill into datatable

//Read the Excel file and fill in datatable .

        public DataTable GetDataTable(string strSheetName)

        {

            try

            {

                string strComand;

                if (strSheetName.IndexOf("|") > 0)

                {

                    /* if Range is provided.*/

                    string SheetName = strSheetName.Substring(0, strSheetName.IndexOf("|"));

                    string Range = strSheetName.Substring(strSheetName.IndexOf("|") + 1);

                    strComand = "select * from [" + SheetName + "$" + Range + "]";

                }

                else

                {

                    //= Images_Path + "" + SaveStudentDetails.FileName;

                    strComand = "select * from [Sheet1$]";

                }

                //HttpPostedFile StudentPhotoFile = SaveStudentDetails.PostedFile;

                string excelConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + FinalPath + ";Extended Properties='Excel 8.0;HDR=NO;'";

                OleDbConnection connection = new OleDbConnection(excelConnectionString);

                OleDbDataAdapter daAdapter = new OleDbDataAdapter(strComand, connection);

                DataTable dt = new DataTable("Datatable");

                DataColumn dc = new DataColumn();

                DataRow dr = dt.NewRow();

                dt.Rows.Add(dr);

                daAdapter.Fill(dt);

                return dt;

            }

            catch (Exception ex)

            {

                throw new Exception("Select location" + ex.Message);

            }

        }

Solid Principles in C#

The SOLID Design Principles and Design Patterns play an important role in achieving all of the above key points.

The SOLID Design Principles are the design principles that help us to solve most of the software design problems. These design principles provide us with multiple ways to move the tightly coupled code between the software components which makes the software designs more understandable, flexible, and maintainable. 

S stands for the Single Responsibility Principle which is also known as SRP.

O stands for the Open-Closed Principle which is also known as OSP.

L stands for the Liskov Substitution Principle which is also known as LSP.

I stand for the Interface Segregation Principle which is also known as ISP.

D stands for Dependency Inversion Principle which is also known as DIP.

Why we need Partial Views in ASP.NET MVC Application?

When we need a common part of the user interface at multiple pages in a web application then we develop a partial view, hence the partial view is a regular view that can be used multiple times in an application and has the file extension .cshtml.

Sometimes we also use a partial view to divide a web page into small parts such as header, footer, and menu on Layout. Other examples are comments in blogging site, shipping and billing address in the invoice in e-commerce site, etc. 

If you are coming from asp.net web-forms background, then you can realize that partial views in MVC are similar to user controls in asp.net web forms. 

use of "New" keyword

Using a new keyword for re-implementing the methods in the child class is optional and if used will give information to hiding.