Visual Basic/VB6 Command Reference

This page aims to be a comprehensive command reference to the MS Visual Basic 6 programming language. String Manipulation Asc Returns the number corresponding to the ASCII code for the first character of string Usage Asc(string) string = string containing character as first letter whose ASCII code is to be found. Example code = Asc("Apple") Here code will get value 65 Chr Returns a string character that corresponds to the ASCII code in the range 0-255. Reverse of the Asc function. Usage Chr(code) code = ASCII code. Example char = Chr(97) Here char gets value "a"https://docs.microsoft.com/fr-fr/office/vba/language/reference/user-interface-help/chr-function. Len Returns the amount of characters in a given string or 0 for Empty. Usage Len(expression) expression = a string or Empty Example mystring = InputBox("Enter a string to test") length = Len(mystring) MsgBox "Length of the string is " & length e.g. where mystring is "Hello", length will be 5. Left Returns a given number of characters from the left hand side of a string Usage Left(string,x) string = string to use x = number of characters Example mystring = InputBox("Enter a string") mystring = Left(mystring, 4) MsgBox "First four characters of your input are " + mystring e.g. where the input mystring is "Hello", the output mystring will be "Hell" Right Returns a given number of characters from the right hand side of a string Usage Right(string, x) string = string to use x = number of characters Example mystring = InputBox("Enter a string") mystring = Right(mystring, 4) MsgBox "Last four characters of your input are " + mystring e.g. where the input mystring is "Hello", the output mystring will be "ello" Mid (Function) Returns a given number of characters from the middle of a string Usage Mid(string, start, length) string = string to use start = character to start at (1 is the first character) length = number of characters Example mystring = InputBox("Enter a string") mystring = Mid(mystring, 2, 3) MsgBox "The second, third, and fourth characters of your input are " & mystring e.g. where the input mystring is "Hello", the output mystring will be "ell" Mid (Statement) Sets a given number of characters in the middle of a string equal to the same number of characters from the beginning of another string Usage Mid(mystring, start, length) mystring = the string to take characters from start = character to start at (1 is the first character) length = number of characters Example mystring = InputBox("Enter a string") Mid(mystring, 2, 3) = "abcd" MsgBox "Your string with abc as the second, third, and fourth characters of your input are " + mystring e.g. where the input mystring is "Hello", the output mystring will be "Habco" Trim Removes leading and trailing spaces from a string Usage Trim(string) string = string to use Example mystring = Trim(mystring) e.g. where the original value of mystring was " Hello ", the new value of mystring will be "Hello". LCase Converts a string to lowercase Usage LCase(string) string = string to use Example mystring = LCase(mystring) e.g. where the original value of mystring was "HELLO", the new value of mystring will be "hello". UCase Converts a string to uppercase Usage UCase(string) string = string to use OR character Example mystring = UCase(mystring) e.g. where the original value of mystring was "Hello", the new value of mystring will be "HELLO". String Creates a string with the specified length of the specified character Usage String(length, character) length = length of string character = character to fill string with Example mystring = String(5,"a") e.g. the new value of mystring will be "aaaaa". Space Creates a string with the specified length of space Usage Space(length) length = length of string Example mystring = Space(5) e.g. the new value of mystring will be "     ". StrConv Returns a converted string as specified. Usage StrConv(string, conversion,LCID) string = string to use conversion = case to convert the string to (lowercase: vbLowerCase, uppercase: vbUpperCase, proper case (first letter in caps): vbProperCase) LCID = optional. The LocaleID, if different than the system LocaleID. Example mystring = StrConv(mystring, vbProperCase) e.g. where the original value of mystring was "HELLO", the new value of mystring will be "Hello". Mathematical Functions Abs Returns the absolute value of a number Usage Abs(number) Example msgbox "The absolute value of -4 is " & abs(-4) Important note! The Abs function only accepts numbers. Non-numeric values generate an error. Cos Returns the cosine of a number Usage Cos(integer) Example msgbox "The cosine of 4 is " & cos(4) Important note! The input angle for all VB trigometric functions should be in radians. To convert degrees to radians, multiply degrees by pi / 180. Sin Returns the sine of a number Usage Sin(integer) Example msgbox "The sine of 4 is " & sin(4) Important note! The input angle for all VB trigometric functions should be in radians. To convert degrees to radians, multiply degrees by pi / 180. Tan Returns the tangent of an angle Usage Tan(integer) Example msgbox "The tangent of 4 is " & tan(4) Important note! The input angle for all VB trigometric functions should be in radians. To convert degrees to radians, multiply degrees by pi / 180. Val Returns the numeric value of a string Uses "." as decimal separator. ( It does not depend on the Regional Settings ) Usage Val(string) Example Val("5") The return value will be 5 Val("10.6") The return value will be 10.6 Val("Hello World") The return value will be 0 (zero) txtOutput.Text = Val(txtNumber1.Text) * Val(txtNumber2.Text) The text box txtOutput will contain the product of the numbers in the txtNumber1 and txtNumber2 text boxes. If either of the text boxes contains a value that cannot be evaluated to a number then the output will be 0 (zero). Rnd Returns a floating point number less than 1 but greater than or equal to 0. Usage Rnd[(number)] You can change the seed the random number generator uses by providing a value as a parameter e.g. Rnd(500) will use the number 500 as the seed in generating random numbers. If you provide a value less than zero then the same number will be returned by the Rnd() function A value of zero will return the most recently generated random number. <li>Providing no value will generate the next random number in the sequence. Providing a positive number will generate the next random number in the sequence using number as a seed. Example myvar = Rnd() * 10 myvar will become a random number between 0 and 10. myvar = (Rnd() * 15) + 25 myvar will become a random number between 25 and 40. myvar = (Rnd(12345) * 50) - 25 myvar will become a random number between -25 and 25 and 12345 will be used as the seed to generate this number. Int Returns the integer portion of a number. Usage Int(n) Where n is the number to return Example Int(10) Returns 10 Int(5.1) Returns 5 Int(5.86) Returns 5 MsgBox "The integer portion of " & myvar & " is " & Int(myvar) & "." NOTE: No rounding will be performed, the decimal portion of the number will simply be removed. If you want to round a number to the nearest whole integer then use CInt. One interesting point to remember about CInt is that if the decimal portion of the number is exactly .5 then it will be rounded UP if the number is odd and rounded DOWN if it is even. For example CInt(1.5) and CInt(2.5) will both return 2. Input and output MsgBox The MsgBox function displays a message in a dialog box, waits for the user to click a button, and returns an Integer value indicating which button the user clicked. Syntax MsgBox(prompt[, buttons] [, title] [, helpfile, context]) The MsgBox function syntax has these parts: PART DESCRIPTION prompt Required. String expression displayed as the message in the dialog box. The maximum length of prompt is approximately 1024 characters, depending on the width of the characters used. buttons Optional. Numeric expression that is the sum of values specifying the number and type of buttons to display, the icon style to use, the identity of the default button, and the modality of the message box. If omitted, the default value for buttons is 0 (which causes only an OK button to be displayed with no icon). title Optional. String expression displayed in the title bar of the dialog box. If you omit title, the application name is placed in the title bar. helpfile Optional. This argument is only applicable when a Help file has been set up to work with the application. context Optional. This argument is only applicable when a Help file has been set up to work with the application. Usage MsgBox(prompt[, buttons] [, title] [, helpfile, context]) or Response=MsgBox(prompt[, buttons] [, title] [, helpfile, context]) The integer value of the button selected will be placed into the Response variable. Button Combinations vbOKOnly vbOKCancel vbAbortRetryIgnore vbYesNoCancel vbYesNo vbRetryCancel Icon Display vbCritical vbQuestion vbExclamation vbInformation Default Button vbDefaultButton1 vbDefaultButton2 vbDefaultButton3 vbDefaultButton4 Examples MsgBox "An error has occurred!",vbExclamation,"Error" Note that since the message is fixed, quotation marks have been used. Response=MsgBox("Yes or no?",vbYesNo + vbQuestion,"Choose one") Note the parenthesis and how the vbYesNo and vbQuestion constants have been combined MsgBox "An error has occurred on line " & lineno, vbExclamation, "Error" InputBox Displays a simple input box for user to enter data Usage Variable=InputBox(Prompt,Title) Variable = variable to which the input value will be stored Prompt = text displayed to the user in the input box Title = title of the input box Examples myint=InputBox("Enter a number","Enter a number") Date and Time Date Returns or sets the current system date Example MsgBox "Today 's date is " & Date & "." Time Returns or sets the current system time Example MsgBox "The time now is " & Time & "." Sidenote: be wary of changing date and time in your program. Many other programs will depend upon the system's date and time being set correctly, so altering it could have a knock on effect. Use date and time changes sparingly, and notify the user if this is being done. Timer Returns the number of seconds since midnight Example NumHrs=Int(Timer / 3600) MsgBox "Currently in hour " & NumHrs WeekdayName Returns the name of a day of the week Usage WeekdayName(x,FirstDayOfWeek) x = integer between 1 and 7 FirstDayOfWeek (OPTIONAL) = the day counted as the first in the week. The default is Sunday. Example DayName=WeekdayName(i,vbMonday) Miscellaneous IsNull Returns true if an expression is null and false otherwise. Example: If IsNull(vntMyVariantVar) Then Debug.Print "vntMyVariantVar is null" Else Debug.Print "vntMyVariantVar is NOT null" End If File Handling Open Open "" & namefile& ".dat" For Binary As #ff Selection If... Then... Else... Performs selection based upon criteria. A cornerstone of any VB program. 'Usage' Single Line Selection If condition Then action Note that only one line can be used with this style of statement Multi Line Selection If condition Then [code to execute if condition is true] EndIf Using Else If condition Then [code to execute if condition is true] Else [code to execute if condition is false] EndIf Condition is a condition which must be met for the code within the statement to be executed. It can make use of the modifiers AND, NOT, OR and XOR (e.g. x=4 AND y > 6). See also the Examples section. Examples Simple one-line selection: If x < 10 then MsgBox "The number is below 10" Slightly more complex one-line selection, using the AND modifier to check two conditions at one time. If x > 10 AND x < 20 then MsgBox "The number is between 10 and 20" Simple multi-line selection. The code between the If... and EndIf statements will be executed only if the condition is met. If Date = 25/12/2006 Then MsgBox "The date is Christmas Day" Call ChristmasDay EndIf Using the Else statement. If the variable i is over 4, the program will exit the subroutine. Otherwise, it will go to the label SaveFile. If i > 4 Then Exit Sub Else Goto SaveFile EndIf Two If... Endif statements are used, one nested within the other. If i is 6 or 7, the code between the inside If...Endif statements is executed. Then if i=7 the first message box will be shown; otherwise (i.e. if i=6) the other will be displayed. For both cases, the final message box will be shown. When nesting selection statements, it's often a good idea to indent them as shown here. If i = 6 OR i = 7 Then If i = 7 Then MsgBox "Today is Sunday" Else MsgBox "Today is Saturday" EndIf MsgBox "Today is the Weekend" EndIf References Selected Functions Glossary