CString::GetLength
int GetLength( ) const;
 Return Value
A count of the bytes in the string.
 Remarks
Call this member function to get a count of the bytes in this CString object. The count does not include a null terminator.
For multibyte character sets (MBCS), GetLength counts each 8-bit character; that is, a lead and trail byte in one multibyte character are counted as two bytes.
 Example
The following example demonstrates the use of CString::GetLength.
// example for CString::GetLength
CString s( "abcdef" );
ASSERT( s.GetLength() == 6 ); 

  在多字节（ANSI）环境里面
  int iCount = 0;
  CString strMyString;  
  strMyString = _T("中文字符");
  iCount = strMyString.GetLength(); //iCount = 8
  strMyString = _T("English char");
  iCount = strMyString.GetLength();//iCount = 12
  strMyString = _T("混合char");
  iCount = strMyString.GetLength();//iCount = 8  
 在这里，GetLength把中文字符当成两个字符来对待。这并不是很符合我们的逻辑。
 、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、
 在Unicode环境里面
  int iCount = 0;
  CString strMyString;  
  strMyString = _T("中文字符");
  iCount = strMyString.GetLength(); //iCount = 4
  strMyString = _T("English char");
  iCount = strMyString.GetLength();//iCount = 12
  strMyString = _T("混合char");
  iCount = strMyString.GetLength();//iCount = 6 在这里，GetLength按我们正常的逻辑把中文字符也看成是一个字符来对待。具有国际通用性
 在VS2008测试通过