優化VB.NET應用程序的性能(1)
2024-07-10 13:05:36
供稿：網友
1) 整數除法運算符 / 和 /
/ 比 / 快10倍 （如果是整數除法并且不需要保留小數）
(2) 賦值運算符 a +=b 和 a = a+b
+= 快
(3) 串聯運算符 & 和 +
用 & 快
（來源：http://www.devcity.net/newsletter/archive/devcity/devcity20040315.htm#ni030)
.net pro: optimize the performance of vb.net applications
operators
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.
compound assignment operators for numbers:
^=
*=
/=
/=
+=
-=
compound operator for strings: &= example:
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.
