Visual Basic Statements

VB.NET > Statements

AddHandler	Call	Class	Const
Continue	Declare	Delegate	Dim
Do...Loop	Else	End	End
Enum	Erase	Error	Event
Exit

RaiseEvent	ReDim	REM	RemoveHandler
Resume	Return	Select...Case	Set
Stop	Structure	Sub	SyncLock
Then	Throw	Try...Catch...Finally	Using
While...End While	With...End With	Yield

Generics and Arrays Example in C#

C# > Generics > Generics and Arrays

Example: Use a single generic method that takes an IList<T> input parameter and iterate through both a list of integers and an array of string.

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

namespace WindowsFormsApplication2

{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)

        {
            string[] str = { "0", "1", "2", "3", "4" };
            List<int> intL = new List<int>();
            for (int x = 0; x < 5; x++)
            {
                intL.Add(x);
            }
            ProcessList<string>(str);
            ProcessList<int>(intL);
        }
        static void ProcessList<T>(IList coll)
        {
            foreach (T item in coll)
            {
                MessageBox.Show(item.ToString());
            }
        }
    }
}

Form VB.NET

VB.NET > Form

Form

Is a representation of any window displayed in an application.

Type

• standard
• tool
• borderless
• floating

Example

Create dialog box in runtime

Dim form1 As New Form()

Dim btnYes As New Button()

Dim btnNo As New Button()
btnYes.Text = "Yes"
btnYes.Location = New Point(5, 5)
btnNo.Text = "No"
btnNo.Location = New Point(btnYes.Left, btnYes.Top + 30)

form1.Controls.Add(btnYes)

form1.Controls.Add(btnNo)

form1.Text = "Confirm Dialog Box"

form1.FormBorderStyle = FormBorderStyle.FixedDialog
form1.MaximizeBox = False
form1.MinimizeBox = False
form1.AcceptButton = btnYes
form1.CancelButton = btnNo
form1.StartPosition = FormStartPosition.CenterScreen

form1.ShowDialog()

Object-Oriented Programming VB.NET

VB.NET > Object-Oriented Programming VB.NET

Visual Basic .NET has been entirely rewritten to be fully object-oriented and everything in Visual Basic .NET can be treated as an object.

OOP language:

• Abstraction
• Encapsulation
• Polymorphism
• Inheritance

Examplea

• Abstract class employee 
• Class with events

System Namespace VB.NET

VB.NET > System namespace

System namespace in VB.NET contains fundamental classes and base classes.

String

•  Concat

Create CDATA section XML C#

C# > XML > XmlDocument > CreateCDataSection

CreateCDataSection creates an XmlCDataSection.
CDATA is a section used to quote or escape blocks of text to keep that text from being interpreted as markup language.

Example:

XmlDocument doc = new XmlDocument();
doc.LoadXml("<product ID='1'></ product>");

//Create a CData section

XmlCDataSection CData;
CData = doc.CreateCDataSection("Size is 10/55");

//Add the new node to the document
XmlElement root = doc.DocumentElement;
root.AppendChild(CData);
doc.Save("C:\\Products.xml");

Result:

<product ID="1">

  <![CDATA[Size is 10/55]]>
</product>

Short type C# Example

C# > Types > short

The short keyword is an integral type.
Range: -32768 to 32767
Size: Signed 16-bit integer

Example:

short k = 32767; // ok
k = 32768; // Error Constant value '32768' cannot be converted to a 'short'

Struct in C# Example

C# > Types > Struct

A struct type is a value type and is typically used for representing lightweight objects (color, zip, point).

• cannot inherit from another struct or class
• can be instantiated without using a new operator.
• can implement an interface
• can contain fields, constructors, methods, operators and events, but
• if many members are required  you should make your type a class instead

Note:  Struct might be more efficient than a class in some scenarios. Using array of thousand of objects will be allocate more memory for referencing each object, so in this case, a struct would is more efficient and less expensive.






Example

        public struct strColor
        {
            public int r, g, b;
            public strColor(int p1, int p2, int p3)
            {
                r = p1;
                g = p2;
                b = p3;
            }
        }

       // Initialize using default and parameterized constructor

       strColor color1 = new strColor();
       strColor color2 = new strColor(10, 20, 30);

      // Declare object. It creates object without using the new  operator

       strColor color;

      //Initialize

       color.r = 10;
       color.g = 20;
       color.b = 30;

SQL Server sp_server_info example

SQL Server > System Stored Procedures   > sp_server_info

Sp_server_info returns a list of attribute names and values for SQL Server.

Example:

exec sp_server_info

Result:

attribute_id  attribute_name       attribute_value

1      DBMS_NAME     Microsoft SQL Server

2      DBMS_VER      Microsoft SQL Server 2012 - 11.0.2100.60 - 11.0.2100.60
10     OWNER_TERM    owner
11     TABLE_TERM    table
12     MAX_OWNER_NAME_LENGTH      128
13     TABLE_LENGTH  128
14     MAX_QUAL_LENGTH      128
15     COLUMN_LENGTH 128
16     IDENTIFIER_CASE      MIXED
17     TX_ISOLATION  2
18     COLLATION_SEQ charset=iso_1 sort_order=nocase_iso charset_num=1 sort_order_num=52
19     SAVEPOINT_SUPPORT    Y
20     MULTI_RESULT_SETS    Y
22     ACCESSIBLE_TABLES    Y
100    USERID_LENGTH 128
101    QUALIFIER_TERM       database
102    NAMED_TRANSACTIONS   Y
103    SPROC_AS_LANGUAGE    Y
104    ACCESSIBLE_SPROC     Y
105    MAX_INDEX_COLS       16
106    RENAME_TABLE  Y
107    RENAME_COLUMN Y
108    DROP_COLUMN   Y
109    INCREASE_COLUMN_LENGTH     Y
110    DDL_IN_TRANSACTION   Y
111    DESCENDING_INDEXES   Y
112    SP_RENAME     Y
113    REMOTE_SPROC  Y
500    SYS_SPROC_VERSION    11.00.2100

sp_tables SQL Server Example

SQL Server > System Stored Procedures   > sp_tables

Returns a list of tables and views that can be queried in the current environment.

Example:

EXEC sp_tables;

 

LINQ Query Expressions C# example

C# > LINQ Query Expressions

Language-Integrated Query (LINQ) is the name for a set of technologies of .NET Framework. This component adds data query  capabilities directly into the C# language.
LINQ expressions are like SQL statements  and can be used to extract and process data from arrays, classes, XML and databases.

Data Source - Query Expression - Execute

Methods

• Single
• FirstOrDefault
• Take
• Join
• Where
• Average

Examples

Example 1.  Fundamental query concepts

            // data source

            int[] int_array = new int[] { 5, 4, 2, 8, 10 };

            // query expression

            IEnumerable<int> intQuery =
                from int_v in int_array
                where int_v >= 5
                select int_v;

            // Execute the query
            foreach (int i in intQuery)
            {
                MessageBox.Show(i.ToString());
            } 
    
Example 2. Order by query

            IEnumerable<int> intQuery =
                from int_v in int_array
                where int_v >= 5
                orderby int_v ascending
                select int_v;

Example 3. Implement RANK function

Example 4. IsNumeric

Example 5. Order By Key Dictionary