Useful VB Commands

[Release] All Vb Codes/Functions

Note I Did not Make this Code List All Credits Go To: Saqib Sajjad

Operators

Here are the VB operators used to perform mathematical operations on one or more variables. Aside from the normal multiply/add/subtract and divide, you will find the AND, OR, Not Equal, MOD and Integer Division operators very useful.

Code:

/ - Normal division 
\ - Integer division (truncates the answer) 
^ - Exponentiation operator 
* - Multiply 
+ - Plus 
- - Minus 
= - Equal 
> - Greater Than 
< - Less Than 
<> - Not Equal 
>= - Greater than or equal 
<= - Less than or equal 

AND - Defines a Boolean value that is the AND of two values 
result = expression1 AND expression2 
OR - Defines a Boolean value that is the OR of two values 
result = expression1 OR expression2 
XOR - Defines a Boolean value that is the exclusive OR of two values 
result = expression1 XOR expression2 
NOT - Defines an opposite Boolean value 
A = NOT B 
EQV - Performs a logical equivalence on two expressions (result is true if both expressions are true) 
result = expression1 EQV expression2 
IMP - Performs a logical implication on two expressions 
result = expression1 IMP expression2 
IS - Determines if 2 variables reference the same object 
result = object1 IS object2 
LIKE - Determines if one string matches a pattern 
result = string LIKE pattern 
MOD - Returns the integer remainder of a division 
i = 27 MOD 5

Math

VB also provides built-in functions which can act on variables. Most are self-explanatory. In my experience, the VAL, RND, and ROUND functions are among the most valuable, so be sure to pay close attention to them!

Code:

Round - Rounds a number to a selectable number of decimal places 
result = round ( tempvariable,2 ) 
Val - Returns the numerical content of a string 
result = Val ("123.4") 
Int - Returns an integer by truncating (different than Fix) 
i = int ( tempvariable ) 
Fix - Returns an integer by truncating (different than Int) 
i = fix ( tempvariable ) 
Hex - Returns the hexadecimal value of any number 
temp$ = hex ( tempvariable ) 
Oct - Returns the octal value of any number 
temp$ = oct ( tempvariable ) 
Tan - Returns the tangent of an angle 
tempvariable1 = tan ( tempvariable2 ) 
Rnd - Returns a random number between 0 and 1 
tempvariable1 = rnd 
Randomize - Initializes the Rnd function so it gives different answers each time 
randomize 
Sgn - Returns the sign of a number 
i = sgn ( tempvariable ) 
Sin - Returns the sine of an angle 
tempvariable1 = sin ( tempvariable2 ) 
Cos - Returns the cosine of an angle 
tempvariable2 = cos ( tempvariable ) 
Abs - Converts a number to a positive value 
i = abs ( tempvariable ) 
Sqr - Returns the square root of a number 
tempvariable1 = sqr ( tempvariable2 ) 
Log - Returns the base 10 logarithm of a number 
tempvariable1 = log ( tempvariable2 ) 
Atn - Returns the arctangent of an angle 
tempvariable1 = atn ( tempvariable ) 
Partition - Sort of an oddball function but segregates values according to ranges 
  
Type Conversions - A variety of conversion functions 
CBool, CByte, CCur, CDate, CDbl, CDec, CInt, CLng, CSng, CStr, CVar

Strings

In my experience these functions are used more than just about any of the other VB built-in functions. The FORMAT, MID, and INSTR functions are incredibly powerful and I use them extensively. If you don't understand what they are, they are worth the time to figure out! The LEN and CHR functions are also valuable as are the variations on the trim and case functions.

Code:

Left - Returns the left n characters of a string 
temp$ = left$ ( teststring$, 4 ) 
Right - Returns the right n characters of a string 
temp$ = right$ ( teststring$, 4 ) 
Trim - Removes leading and trailing spaces of a string 
temp$ = trim$ ( teststring$ ) 
LTrim - Removes only the leading spaces of a string 
temp$ = ltrim$ ( teststring$ ) 
RTrim - Removes only the trailing spaces of a string 
temp$ = rtrim$ ( teststring$ ) 
UCase - Makes all characters upper case 
temp$ = ucase$ ( teststring$ ) 
LCase - Makes all characters lower case 
temp$ = lcase$ ( teststring$ ) 
Mid - Returns n characters from a string, starting a any position 
temp$ = mid$ ( teststring$, 1, 4 ) 
Len - Returns the length of a string (how many characters it has) 
temp$ = len ( teststring$ ) 
LSet - Positions a string inside another, flush to the left 
temp$ = lrset ( teststring$ ) 
RSet - Positions a string inside another, flush to the right 
temp$ = rset$ ( teststring$ ) 
Format - Returns a string formatted according to a user-defined format 
temp$ = format$ ( teststring$, "####.0" ) 
String - 
temp$ = left$ ( teststring$, 4 ) 
Chr - Returns the string representation of a number 
temp$ = str$ ( 32 ) 
Asc - Returns the ASCII code of a single character 
temp$ = asc ( "A" ) 
Space - Returns n spaces 
temp$ = space$ ( 15 ) 
Instr - Determines if one string is found within a second string 
i = Instr (starthere, string1, string2) 
InStrRev - Determine if one string is found in a second, starting at the end 
i = InStrRev (string1, string2, start) 
StrComp - Compares two strings 
result = StrComp (string1, string2) 
StrConv - Converts the case of a string's characters 
StrConv (string, vbuppercase) 
StrReverse - Reverses character order in a string 
StrReverse (string1) 
Replace - Replaces each occurrence of a string 
Replace (bigstring, searchstring, replacementstring) 
FormatCurrency - Returns a string using a currency format 
FormatCurrency(var1, 2) 
FormatDateTime - Returns a date or time expression 
FormatDateTime("3/2/99",vbShortTime) 
FormatNumber - Returns a number formatted according to a variety of options 
FormatNumber(var1, 2) 
FormatPerCent - Returns a number formated as a percent 
FormatPerCent(var1, 2)

\

Arrays

Every programmer eventually uses arrays. Mostly they're pretty easy to understand. Take note, however, that you can resize an array with REDIM without losing the data. For details, see the PRESERVE keyword in the HELP entry on REDIM. If you use the LBound/UBound in your code instead of hard-coding the dimension of the array, you can later change the size of the array without touching your code!

Code:

Option Base - Determines whether the lowest range of an array is 0 or 1 
option base 1 
Erase - Erases all values of an array 
erase (arrayname) 
Dim - Creates an array 
dim arrayname(25) 
Redim - Resets the bounds of an array (has option to save values) 
redim arrayname(28) 
UBound - Returns the upper dimension of an array 
i = ubound (arrayname) 
LBound - Returns the lower dimension of an array 
i = lbound (arrayname) 
Filter - Returns a subset of an array based on a filter 
Filter (inputarray, searchstring) 
Array - Yes, there is a function called array. It returns an array that has been filled with data from a list. It allows you to put the actual data values in the code to avoid having the user input it or to avoid having to read it from a file 
ArrayName = Array (10, 20, 30) 
Join - Concatenates strings within an array

File Handling (Generic)

While VB is working on a better approach (FileSystemObject), the built-in file handling statements are still the only way to access data other than through the VB database capabilities. Your skills in this area can make or break your ability to work with various formats. The OPEN/CLOSE statements are critical to success, but the LOF, EOF, and LEN functions are used even more often! It's also a given that you'll use the DIR function regularly.

Code:

Dir - Returns a filename that matches a pattern 
temp$ = Dir ("*.*") 
CurDir - Returns the current directory 
temp$ = CurDir 
MkDir - Creates a directory 
mkdir ( "newdirectoryname" ) 
ChDir - Changes the current directory to a new location 
chdir ( "newdirectoryname" ) 
ChDrive - Changes the current drive 
ChDirve "A" 
RmDir - Removes the indicated directory 
rmdir ( "directoryname" ) 
Freefile - Returns an unused file handle 
i = freefile 
Open - Opens a file for access, locking it from other applications 
open "filename" for input as #1 
Close - Closes a file so that other applications may access it 
close #1 
LOF - Returns the length of a file in bytes 
i = lof ( #1 ) 
EOF - Returns a boolean value to indicate if the end of a file has been reached 
statusvariable = eof ( #1 ) 
Name As - Renames a file 
name "filename1" as "filename2" 
Kill - Deletes a file 
kill "filename" 
Fileattr - Returns attribute information about a file 
i = int ( tempvariable ) 
GetAttr - Returns attributes of a file or directory 
i = GetAttr("c:\windows\temp") 
SetAttr - Sets the attributes of a file 
SetAttr pathname, vbHidden 
Reset - Closes all disk files opened by the OPEN statement 
Reset 
FileDateTime - Returns data file was created or last edited 
FileDateTime ( filename ) 
FileLen - Returns length of file in bytes 
FileLen ( filename ) 
FileCopy - Copies a file to a new name 
FileCopy sourcefile, destinationfile 
Lock - Controls access to a part or all of a file opened by OPEN 
Lock #1 
UnLock - Restores access to a part or all of a file opended by OPEN 
UnLock #1 
Width # - Set the output line width used by the OPEN statement 
Width #2, 80

File Handling - ASCII-specific

While VB is working on a better approach (FileSystemObject), the built-in file handling statements are still the only way to access data outside of a data base. Your skills in this area can make or break your ability to work with various formats. The OPEN/CLOSE statements are critical to success, but the LOF, EOF, and LEN functions are necessary to build useful code.

Code:

Line Input - Reads an entire line of ASCII text 
line input #1, tempvariable$ 
Write - Puts data in a file, with separators for the data 
write #1, tempvariable$ 
Print - Puts data in a file with no separators 
print #1, tempvariable$ 
Spc - Used in a print statement to move a number of spaces 
Print #2, var1; spc(15); var2 
Tab - Used in a print statement to move to TAB locations 
Print #2, var1; Tab(20); var2

File Handling - Binary-specific

VB also support features which allow you to access a file on a byte-by-byte basis. The good thing about it is that you have more control, the bad thing is that you may have to write more code. Generally, a programmer will use the option (ASCII or Binary access) according to the least code he has to write. For binary access the Get/Put are equivalent to the Line Input and Print functions used in ASCII text file access. The big difference between the two is that binary access will read (Get) an exact number of bytes of data, and the reading can start at any byte within the file.

Code:

Get - Reads data from a file 
get #1, anyvariable 
Put - Puts data into a file 
put #1, anyvariable 
Seek - Moves the current pointer to a defined location in a file 
seek #1, 26 
Input 
input #1, anyvariable 
Loc - Returns current position with an open file 
i = Loc(#2)

Declarations

I probably get more questions about the functions in this section than about any other group. In general, the concepts are pretty simple, but the details of getting it exactly right can cause even experienced programmers trouble. Focus on understanding Dim/ReDim/Public/Private/Sub/Function/Type and Set. However, they're all useful at times, so bear down and commit these to memory. I'll try to add more text and tips on these than I have on the others.

Code:

Dim - Used to define a variable as a certain type 
i = dim i as integer, r as single 
You can use the Option Explicit to make sure that VB forces you to declare every variable you use. DIM is that simplest way to declare a variable 
ReDim - Used to change the dimensions of a dynamic array 
redim arrayname(37) 
Don't be afraid of this one. You can use ReDim to create an array whose size grows by 1 every time you want to add a number to it. Then, the UBound tells you how many numbers you've added. 
Static - Establishes a procedure variable which keeps its value between calls 
static i as integer 
For example, if you want to keep track of how many times you've been in a procedure, set a counter as STATIC and increment it by one for each visit to the procedure. It will never go away until the program is terminated. 
Public - Creates a variable which can be accessed outside its own procedure 
public i as integer 
Even if you're the only programmer writing code in your application, use of Private vs Public will help catch errors if you inadvertently try to access an out-of-scope variable 
Private - Creates a variable that can be read only in its own procedure or module, according to where the declaration took place. 
private i as integer 
Use this as often as possible to avoid unnecessary exposure of your variables to coding mistakes. 
Sub - Defines a procedure which can execute a block of code 
Sub NewProcedure (var1 as integer, var2 as string) 
Be sure to check out HELP for how to handle Sub arguments. There are more questions and mistakes made concerning the use of arguments than just about anything else I've seen. 
Function - Declares a procedure which can return a value 
Function NewFunction (var1 as integer, var2 as string) as SINGLE 
This is actually the most versatile of the Sub/Function procedure types. It can do anything a Sub can do as well as returning a value for use in an expression. 
Call - Transfers control to a Sub or Function (is optional) 
Call Procedure 1 
Since the use of CALL is optional, forget you ever saw it 
CallByName - Executes a method of an object or set/returns a property 
CallByName(form1,procedurename,vbMethod) 
The really cool thing about this is that you don't have to hardcode a procedure call. Just use a string variable with the name of the procedure to call. 
Option Explicit - Instructs VB to force an explicit declaration of all variables 
Option Explicit 
You're borderline stupid if you don't use it to catch typing errors. Set up the VB IDE to automatically include this in all projects. 
Option Compare - Instructs VB on how to make string comparisons 
Option Compare Binary 
This can add case-insensitivity for those times when you don't want to hard-code it 
Option Private - Prevents a module's content from being referenced outside a project. 
Option Private Module 
Generally doesn't apply to most VB applications. If you find a good use for it let me know. 
Property Get - Declares how to get the value of a property 
Property Get Name() 
You won't use this much until you get into creating classes of your own 
Property Let - Declares how to assign a value to a property 
Property Let Name() 
You won't use this much until you get into creating classes of your own 
Property Set - Declares how to set a variable reference to an object 
  
You won't use this much until you get into creating classes of your own 
Set - Assigns an object reference to a variable 
Set X = form1.txtInputFromUser 
Very useful for making code more readable or simply to cut down on how much typing you have to do! 
Let - Precedes assignment of a value to a variable 
Let i = 3 
It's optional, no one uses, so forget you ever saw it 
Type...End Type - Creates a user defined part type which consists of standard VB data types 
type anytypename 
one as string 
two as integer 
three as boolean 
End Type 
This is a really excellent way to keep several kinds of data under one variable name. Plus, you can PUT or GET a user-defined type with a single line of code. 
Const - Creates a variable whose value is fixed 
const anyname 
Basically, use this to give easy to remember names to values. For example, suppose you use the value 37.2 a lot in your code, then if you put CONST MyAge = 37.2 in your code you'll be able to insert the MyAge where the 37.2 should have gone. Easier to type and easier to read. Also, you can chane the value of the constant by changing only the declaration line of code, rather than searching out every place the value was used! 
Declare - Used to define a procedure that exists in another file 
declare functionname (arg1 as integer, arg2 as string) as integer 
  
ArrayName = Array (10, 20, 30) 
Implements - Specifies a class to be implemented in a module 
  
Friend - Allows procedure to be callable from modules outside the class 
  
GetObject - Return a reference to an ActiveX component 
  
CreateObject - Creates and returns a reference to an ActiveX object 
  
GetAutoServerSettings - Returns information about the state of an ActiveX component's registration. 
  
Enum - Declares a type for an enumeration 
  
Event - Declares a user-defined event 
  
TypeName - Returns the type of data in a variable 
  
VarType - Returns the type of data in a variable 
  
DefType - Sets the default data type of variables 
DefInt A-Z 
IS - A variety of data type or status checking options 
IsArray, IsBindable, IsBroken, IsDate, IsDirty, IsEmpty, IsError, IsMissing, IsNull, IsNumber, IsObject, IsReady, IsRootFolder

Miscellaneous

In this list you'll find some of the features of VB about which I get a lot of email questions! The MsgBox is easily the most used of the bunch. It handles all of the "Y/N" queries to your user so get to know it well. Also, the DoEvents, Shell, and Command functions are indispensable in certain occasions so make sure you know when they should be used.

Code:

MsgBox - A built-in dialog box that gives a message and allows a user input 
i = msgbox "Read this!", vbokonly, "Test Message" 
DoEvents - Allows VB to complete pending tasks 
doevents 
Shell - Executes a 2nd program from within the current program 
shell "notepad.exe" 
Note - VB does not wait for the Shell'd program to quit before executing the next line of code! 
Command - Gives any text that followed a VB .EXE execution command 
temp$ = command 
Environ - Returns the system environmental space content 
temp$ = environ 
Beep - Makes the computer beep once. 
beep 
InputBox - A built-in dialog box that allows entry of a text string 
inputbox "Input a value!", 5 
AddressOf - Provides an entry point for an external program to use a procedure 
AddressOf ( procedurename ) 
AppActivate - Activates an applications window 
AppActivate ( windowtitle ) 
RaiseEvent - Fires an event declared at module level 
RaiseEvent ProcedureName 
Load - Load an object 
load form1 
Unload - Unload an object 
Unload form1 
LoadPicture - Load a picture into a control property 
form1.picture = loadpicture (filename) 
SavePicture - Save a picture to a file 
SavePicture(form1.picture,filename) 
LoadResData - Load the data from a resource file 
LoadResData(index,format) 
LoadResString - Load a string from a resource file 
LoadResString(index,format) 
SendKeys - Send keys to another app as though they were from the keyboard 
Sendkeys {DOWN} 
QBColor - Returns a value corresponding to the original QB values 0-15 
form1.backcolor = QBcolor (12) 
RGB - Returns a color value by inputting the red, green, and blue parts 
form1.backcolor = RGB (12,128,256) 
Me - Refers to the current object, usually the active form 
print Me.caption

Useful VB Commands

Post a Reply

Tags for this Thread