.NET Pro: Optimize the Performance of VB.NET Applications
by Mike McIntyre
Division: \ V.S. /
Divide integral values with the \ (back slash) operator when you do not need decimal points or fractional values. The \ operator is the integral division operator and it is up to 10 times faster than the / (forward slash) operator.
Compound Assignment Operators: a += b V.S a = a + b
Compound assignment statements first perform an operation on an argument before assigning it to another argument. Example:
a += b
In the example above, b is added to the value of a, and that new value is then assigned to a. Compound assignment operators are more concise than their constituent operators (separate + and =). Compare the statement above to the one below. The statement above is a shorthand equivalent of the statement below.
a = a + b
Compound assignment operators are faster. If you are operating on an expression instead of a single variable, for example an array element, you can achieve a significant improvement with compound assignment operators.
Dim a As String = "First " a &= "Name"
Result: First Name
Concatenation: & V.S. +
Use the & concatenation operator instead of the + operator to increase the speed of concatenations. Performance of the & and + operators are only equivalent if both operands are type String. If not, the + operator is late bound and must perform type checking and conversions.