1. 1 Microsoft® Visual Basic®.NET Language # 1

2. 2 Variable Declaring Variable Dim {VariableName} As {Type} Dim {VariableName} As {Type} = {value} Example: Dim var1 As String Dim Var2, Var3, Var4 As String Example: Dim var1 As String = "Hello World"

3. 3 Data Types Five Categories Numeric Boolean String Date Object Integrated in the common language runtime 2 Varieties of Data Types Value Types Reference Types

4. 4 Numeric Data Types Data TypeMemory Representation Stores Byte1 byte Positive integer value 0 to 255 Short (Int16)2 bytes Integer value -32768 to 32767 Integer (Int32)4 bytes Integer value -2,147,483,648 to 2,147,483,647 Long (Int64)8 bytes Vary large integer value. -2 63 to (2 63 -1) Single4 bytes Single-precision floating-point number. Double8 bytes Double-precision floating-point number. Decimal16 bytes Vary-Vary large integer and floating-point number

5. 5 Not Number Data Types. Boolean True / False String Store only text data. Character Store only one character. DateTime Store Date and Time Data. Example : Var1 = #01/01/2003# Var2 ="Sep 1,1977" Var3 = #01/01/2003 6:25:11 PM# Var4 = Now()

6. 6 Value Types (Numeric, Boolean, String, Date) Store Data in Stack Memory Function A Dim Var1 As String = "AAA" Call B End Function Function B Dim Var2 As String = "BBB" Call C End Function Function C Dim Var3 As String = "CCC" End Function Stack Memory (LastInFirstOut) Var1="AAA" Var2="BBB" Var3="CCC"

7. 7 Reference Types (Object) Store Variable in Stack Memory Store Data in Heap Memory Function A Dim Var1 As ObjA Var1 = New ObjA Var1.Data = "ZZZ" End Function Stack Memory Var1 ObjA Heap Memory Data = "ZZZ" GC

8. 8 Data Type Functions GetType( {Variable} ) IsNumeric( {Variable} ) IsDate( {Variable} ) IsReference( {Variable} ) Conversion Data Types CBoolCByteCChar CDateCDblCDec CIntCLngCShort CSngCStrCType

9. 9 Parse Method To convert a numeric string to a numeric or others, use the Parse method To Ignore Commas, Use the NumberStyles.AllowThousands Flag Dim MyString As String = “12345” Dim MyInt As Integer = Integer.Parse(MyString) MyInt += 1 Console.WriteLine(MyInt) ‘ The output to the console is “12346” Dim MyString As String = “123,456” Dim MyInt As Integer = Integer.Parse(MyString, _ Globalization.NumberStyles.AllowThousands) Console.WriteLine(MyInt) ‘ The output to the console is “123456”

10. 10 Constant Once a constant has been declared Cannot change value. Process faster than variable. Const { ConstantName } As Type = Value Example : Const pi As Double = 3.14159265358979

11. 11 Array Set of data which have the same type. Zero based. Declaring Array Dim MyString (5) As String MyString(3) = "Happy" Dim str as String str = MyString(3)‘str = "Happy" MyString(5) MyString(4) MyString(3)Happy MyString(2) MyString(1) MyString(0)

12. 12 String Trim method remove spaces Pad method Expand a specific number of characters Dim MyString As String = “ Big ” Dim TrimString As String = MyString.Trim() Console.WriteLine(TrimString) ‘The output to the console is “Big” Dim MyString As String = “Hello World!” Console.WriteLine(MyString.PadLeft(20, “-”)) ‘The output to the console is “--------Hello World!”

13. 13 Changing Case Methods that compare strings and characters are case- sensitive Convert the case of strings that are entered by users before comparing them To change the case of a string use: String.ToUpper String.ToLower Dim MyString As String = “hello world!” Console.WriteLine(MyString.ToUpper()) ‘The output to the console is “HELLO WORLD!” Dim MyString As String = “HELLO WORLD!” Console.WriteLine(MyString.ToLower()) ‘The output to the console is “hello world!”

14. 14 Split and Join Split method breaks up a string into an array of substrings String is broken at positions indicated by the specified separator characters parameter If the separator parameter is Nothing, the white-space characters are assumed to be the separator Join method concatenates a specified separator between string array A specified separator string is placed between each element of a string array Dim Line As String = “hello world” Dim Words() As String = Line.Split(“ ”) ‘Words(0) = “hello” and Words(1) = “World” Dim MyString() As String = {“apple”, “orange”, “grape”, “pear”} Dim JoinString as String = String.Join(“/”, MyString, 0, 3) ‘JoinString = “apple/orange/grape”

15. 15 Length and IndexOf Length Method Gets the number of characters in this instance IndexOf Method Reports the index of the first occurrence of a string or one or more characters, within this instance. Dim MyString As String = “Hello World!” Console.WriteLine(MyString.Length()) ‘The output to the console is “12” Dim MyString As String = “Hello World!” Console.WriteLine(MyString.IndexOf(“or”) ‘The output to the console is “7”

16. 16 Operators Arithmetic Operators + - * / += -= *= /= A = 2 + 3 B += 5 C = B / 2 String Operators + & Message = "Hello " + Name Boolean Operators = = <> And Or Not AndAlso OrElse If A=5 AndAlso B>6 Then