base keyword C#

C# > Keywords > Base

Base is used to access members of the base class from within a derived class

Example

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;

namespace WindowsFormsApplication1

{
    public partial class Form2 : Form
    {
        public class Animal
        {
            protected string type = "";
            public virtual string GetAnimalInfo()
            {
               return(type); 
            }
        }
        class Dog : Animal
        {
            private string name = "";
            public Dog(string name)
            {
                base.type = "dog";
                this.name = name;
            }
            public string GetAnimalInfo()
            {
                // Calling the base class GetInfo method:
                string type = base.GetAnimalInfo();
                return (name + " is a " + type);
            }
        }
        public Form2()
        {
            InitializeComponent();
        }
        private void Form2_Load(object sender, EventArgs e)
        {
            Dog dog = new Dog("Tashi");
            string AnimalInfo = dog.GetAnimalInfo(); // "Tashi is a dog"
         }
    }
}

this C#

C > Keywords > This

Refers to the current instance of the class.

Example

1.This is used to qualify the FirstName and LastName

class Person

{

            private string FirstName;

            private string LastName;

            
            public Person(string FirstName, string LastName)

           {

                this.FirstName = FirstName;

                this.LastName = LastName;

            }

}

2. Call one constructor from another

Insert values and create a temporary table from a dynamic query SQL Server

SQL Server > Scripts > Insert dynamic temp table

Global temporary tables are visible to any user and any connection after they are created, and are deleted when all users that are referencing the table disconnect from the instance of SQL Server

DECLARE @sql varchar(max)

IF object_id('tempdb.dbo.##MyTemp') Is Not Null
       DROP TABLE ##MyTemp
SET @sql =
'SELECT * INTO ##MyTemp FROM (select name from sys.all_objects ) as tbl'
Exec (@sql)
go
SELECT * FROM ##MyTemp

Modulo operator SQL Server

SQL Server > Operators > Modulo

Modulo operator (%)
Returns the remainder of one number divided by another


Example:

SELECT 39 % 7 AS Remainder

Result:
4

DATALENGTH SQL Server

SQL Server > Built-In Functions > DATALENGTH

Returns the number of bytes used to represent any expression

Example:

IF EXISTS(SELECT name FROM sys.tables

      WHERE name = 'test')
   DROP TABLE test;
GO

CREATE TABLE test
(
 c1 varchar(5),
 c2 char(5),
 c3 nvarchar(5)
);
GO

INSERT INTO test VALUES ('1', '1','1'), ('22', '22', '22'),('333', '333', '333');

GO
SELECT 
    DATALENGTH(c1) AS 'Varchar Column',
    DATALENGTH(c2) AS 'Char Column',
    DATALENGTH(c3) AS 'NVarChar Column'
FROM
    test;
GO

Result:

Varchar Column      Char Column  NVarChar Column

1                   5             2
2                   5             4
3                   5             6

Replicate SQL Server

SQL Server > Built-In Functions > REPLICATE

Repeats a string with specified number of times.

Example:

SELECT REPLICATE ('a',5)

Result:

aaaaa

STUFF function SQL Server

SQL Server > Built-in Functions > STUFF

STUFF inserts a string into another string

STUFF ( expression , start , length , replaceWith )

Example:

 

SELECT STUFF('abcdef', 1, 2, 'hg');

Result:
hgcdef