Working with files in C#

C# > IO

IO allow reading and writing to files and data streams, and types that provide basic file and directory support.

Directory class

Path methods

• GetTempPath
• GetRandomFilename
• GetFileName

IO

• Read-write binary
• MemoryStream
• Ports
• FileInfo Class
• File Class
• DirectoryInfo

Examples:

• Search for files

String Type C#

C# > Types > String

String type represents a sequence of Unicode characters and is a reference type.

Methods

• StartWith

Example:

string a = "Hello";
string b = " world";
// Append ! to contents of b
b += "!";
MessageBox.Show (a + b);

What is C#

C# is modern, multi-paradigm,  strongly-typed, object oriented  and high level programming language.
C# is an elegant language that enables you to build a variety of secure and robust applications that run on the .NET Framework. With C# you can create Windows client or Web applications, XML Web services, distributed components, client-server applications, database applications, etc.

The language of C# is very easy for anyone familiar with C, C++ or Java.

• Types
• Keywords
• Reflection
• Delegates
• Generics
• LINQ
• Modifiers
• Files & IO
• InteropServices
• Indexers
• Operators
• Printing
• Serialization
• Statements
• System
• Controls
• Cursors
• Text
• Form
• Design patterns

System

• .Net
• Diagnostics
• System.Data
• Security
• XML

Reflection C#

C# > Reflection 

Reflection offers the possibility   to describe assemblies, modules and types. It enables you to access the attributes. 
A compiled C# program is a relational database called metadata.

• Find classes implementing interface

Example:

using System;

using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace csharp

{
    public partial class Form1 : Form
    {
        public static int mNumber = 10;
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            Type objType = typeof(Form1);
            FieldInfo field = objType.GetField("mNumber");
            object objValue = field.GetValue(null);
            MessageBox.Show(objValue.ToString());
        }
    }
}

Linked Server (SQL Server)

SQL Server > Linked Server

A linked server allows the SQL Server Database Engine to execute commands against OLE DB data sources.
Linked servers are configured to enable the Database Engine to execute a Transact-SQL statement to another instance of SQL Server or another database such as Oracle.
OLE DB data sources can be configured as linked servers like Microsoft Access and Excel.

Advantages:

• access data from outside of SQL Server.
• execute distributed commands( queries updates, transaction) to  heterogeneous data sources

Examples:

Add Microsoft Access as linked server

Microsoft SQL Server

Microsoft SQL Server is a relational database management system developed by Microsoft.
SQL Server supports ANSI SQL, the standard SQL language like all major RBDMS.
SQL Server contains own SQL implementation named T-SQL.
SQL Server Management Studio (SSMS) is SQL Server interface tool.

• Built-in Functions
• Operators
• System stored procedures
• SQL Statements
• Temporary tables
• Data Types
• Catalog Views
• Transact-SQL
• Deadlocks
• XML Data

SQL Server script return the last stored procedures modified in the last n days

SQL Server > sys.objects > Last modified stored procedures

Example

declare @nmb_days int = 10
SELECT * FROM sys.objects 
WHERE TYPE = 'P' 
AND DATEDIFF(D,modify_date, GETDATE()) < @nmb_days