Mega Code Archive

If - starts a conditional expression to determine what to do next

1 if Condition then Statement; 2 if Condition then Statement else Statement; Description The If keyword is used to control the flow of code depending on the logical result of the given condition. There are two forms of the If statement - one with an else clause, the other not. If works as follows : If the condition is true, then the first statement is executed. If false, then this statement is bypassed. If there is an else statement, it is executed instead. In all cases, the Statement clause must be a contained in a begin/end block if it is longer than one statement in length. Notes It is an easy mistake to make, but Delphi insists on no ';' after the then statement if an else statement follows. Related commands Boolean Allows just True and False values Else Starts false section of if, case and try statements End Keyword that terminates statement blocks Then Part of an if statement - starts the true clause Example code : Illustrate the different flavours of the if statement begin // Illustrate a simple if statement that executes true If True then ShowMessage('True!'); // Illustrate the same, but with multiple actions If 1 = 1 then begin ShowMessage('We now have'); ShowMessage('multiple lines'); end; // Illustrate a simple if statement that fails If 1 = 2 then ShowMessage('1 = 2'); // Illustrate an if then else statement // Note the lack of a ';' after the 'then' clause If False then ShowMessage('True') else ShowMessage('False'); // Nested if statements - Delphi sensibly manages associations If true then If false then ShowMessage('Inner then satisfied') else ShowMessage('Inner else satisfied') else ShowMessage('Outer else satisfied') end; Show full unit code True! We now have multiple lines False Inner else satisfied