VB 转 C#
dim temStr
tempStr = "abcdefghijk "

StrConv(Left(StrConv(temStr, vbFromUnicode), 4), vbUnicode)
'他将返回 "abcdefgh "
tempStr = "中华人民共和国 "
StrConv(Left(StrConv(temStr, vbFromUnicode), 4), vbUnicode)
'他将返回 "中华人民 "

先求助把它转换成C#

[解决办法]
string tempStr;
byte[] vBytes;
tempStr = "abcdefghijk ";

vBytes = Encoding.Default.GetBytes(tempStr);
MessageBox.Show(Encoding.Default.GetString(vBytes, 0, 4 * 2));

tempStr = "中华人民共和国 ";
vBytes = Encoding.Default.GetBytes(tempStr);
MessageBox.Show(Encoding.Default.GetString(vBytes, 0, 4 * 2));