C # specify the length of a Chinese/English string

// Whether the character is a Chinese character
Public bool IsChinese (char c)
{
Return (int) c >=0x4e00 & (int) c <= 0x9FA5;
}
// Get the byte length
Private int getLengthb (string str)
{
Return System. Text. Encoding. Default. GetByteCount (str );
}

// C # specifies the length of the string, startidx from 0 by gisoracle@126.com
Public string getStrLenB (string str, int startidx, int len)
{
Int Lengthb = getLengthb (str );
If (startidx + 1> Lengthb)
{
Return "";
}
Int j = 0;
Int l = 0;
Int strw = 0; // character width
Bool B = false;
String rstr = "";
For (int I = 0; I <str. Length; I ++)
{
Char c = str [I];
If (j> = startidx)
{
Rstr = rstr + c;
B = true;
}
If (IsChinese (c ))
{
Strw = 2;
}
Else
{
Strw = 1;
}
J = j + strw;
If (B)
{
L = l + strw;
If (l + 1)> = len) break;

}

}
Return rstr;

 

}

Private void button4_Click (object sender, EventArgs e) // test by yl gisoracle@126.com
{
MessageBox. Show (getStrLenB ("gisoracle welcomes you gisoracle", 0, 10); // gisoracle
MessageBox. Show (getStrLenB ("gisoracle welcome gisoracle", 1, 10); // isoracle Huan
MessageBox. Show (getStrLenB ("gisoracle welcomes you gisoracle", 2, 10); // isoracle Huan
}