last updated 11/21/2010

REALBasic How To's

 

val( ) --How to convert a Text/String to a Number/Integer (use the val( ) method to convert the value from a String in order to do a mathematical operation)

Dim numberString as String

numberString = "5"

Textfield1.text = val(textfield2.text) + val(numberString)

str( ) --How to convert an Integer/Double (Number) to a String/Text (use the str( ) method to convert a mathematical number to a String in order to display it in a text field such as a StaticText.text or Textfield.text)

Dim num1 as Integer

Textfield1.text = str(val(textfield2.text) + val(numberString))

or

num1 = val(textfield2.text) + val(numberString)

textfield1.text = str(num1)

How to use a radioButon

The value of RadioButton.value is set to True or False depending on whether the RadioButton is checked and False if it is not checked.

For example

if RadioButton1.value = true then

Msgbox "You have picked RadioButton1"

elseif RadioButton1.value = false then

Msgbox "RadioButton1 was not picked"

end if

Common Syntax Errors to Look out for

• val(Textfield1.text)= val(Textfield2.text) + val(Textfield3.text) Wrong- val in NOT allowed on the left side of the assignment operator (=). To correct this statement you need to ensure that the right side of the assignment statement matches the variable name's Data Type on the left. For example: Textfield1.text = str(val(textfield2.text) + val(textfield3.text)) would work.
• StaticText1.text = val(Textfield1.text) + val(Textfield2.text) Wrong -This statement is incorrect because the right side of the assignment statement( val(Textfield1.text) + val(Textfield2.text) does not evaluate to the same Data Type as the variable on the left (StaticText1.text). In this case right side is an Integer, and the left hand side is a String. The rules do not allow an Integer to be assigned to a String value. Again you would have to convert the right side to a string as demonstrated in the above example, so that both sides are compatible.
• The following code will give you a syntax error. Don't forget to Dim myNum as an Integer.
  • Dim r as New Random
  • myNum=r.inRange(1,10)
  • StaticText1.text = str(myNum)
• Msgbox "The Random Number is = " myNum - This will generate a syntax error for two reasons. 1st the code is missing a "+" the concatenator operator between "The Random Number is = " + myNum and seconnd myNum has to be converted to a str. The msgbox can be rewritten in two ways - Msgbox "The Random Number is = " + str(myNum) or Msgbox "The Random Number is = " + StaticText1.text

For an assignment the name goes on the left side of the = and the value goes on the right side.

Excerpt from REALbasic By Matt Neuburg (for educational purposes only)

lvalue = rvalue

for example:

Dim StudentName as String

StudentName = "Jennifer"