C#减少垃圾回收压力的字符串操作详解

string filter=“”;//不建议 string filter=string.Empty; //建议

//不推荐的写法if(s1.ToUpper()==s2.ToUpper()) …;//推荐的写法if(String.Compare( s1, s2, true ) == 0) …;

//不建议： 
string s = null; 
for (int i = 0; i < 10000; i++) 
{ 
s += i; 
} 
//建议： 
StringBuilder sb = new StringBuilder(); 
for (int i = 0; i < 10000; i++) 
{ 
sb.Append(i); 
} 
string t = sb.ToString();

StringBuilder sb = new StringBuilder(); 
for (int i = 0; i < 10; i++) 
{ 
 sb.Append(i); 
} 
string s = sb.ToString(); 
//建议修改为 
StringBuilder sb = new StringBuilder(256); 
for (int i = 0; i < 10; i++) 
{ 
 sb.Append(i); 
} 
string s = sb.ToString(); 

StringBuiler sb = new StringBuilder(256); 
 ...... 
sb.Remove(0, sb.Length); //不建议 
sb.Length = 0; //建议 

static void test() 
{ 
 StringBuilder sb = new StringBuilder(256); 
 for (int i = 0; i < 100; i++) 
 { 
  sb.Append(i); 
 } 
 string t = sb.ToString(); 
 ……//其他不使用变量sb的代码段 
 sb.Length = 0; //去掉该句手工清空sb代码，会更早释放内存 
}