1 字符串分割

string url = "http://asdfsfd asdf asdfsdf ";
string[] sss = GetString(url," ");
foreach(string str in sss)
{
Response.Write(str.ToString() +" ");
}

private string[] GetString(string str,string cutStr)
{
char[] cutChar = cutStr.ToCharArray();
string[] sArray = str.Split(cutChar);
return sArray;
}

2 字符串截取

public static string GetFirstString(string stringToSub, int length)
{
Regex regex = new Regex("[\u4e00-\u9fa5]+", RegexOptions.Compiled);
char[] stringChar = stringToSub.ToCharArray();
StringBuilder sb = new StringBuilder();
int nLength = 0;
bool isCut=false;
for(int i = 0; i < stringChar.Length; i++)
{
if (regex.IsMatch((stringChar[i]).ToString()))
{
sb.Append(stringChar[i]);
nLength += 2;
}
else
{
sb.Append(stringChar[i]);
nLength = nLength + 1;
}

if (nLength > length)
{
isCut=true;
break;
}
}
if(isCut)
return sb.ToString()+"...";
else
return sb.ToString();
}

3.取子串函数SubString
string tmp2 = tmp1.SubString(0,3);
相当于vb.net中的mid
tring str="abcdefg";
string str1=str.Substring(2,3);//str1="cde"

4.C#中有什么函数可以判断某一字符串中是否存在着某一字符？如："akkk*kkk"是否有“*”？

string s = "akkk*kkk";
int i = s.IndexOf("*");

if( i != -1) 包含
else 不包含

5.右对齐此实例中的字符，在左边用指定的 Unicode 字符填充以达到指定的总长度。
[C#] public string PadLeft(int, char);
str = "256";
str = str.PadLeft(5,"0"); //str = "00256"