string vs. w/char*

[Tyro[a.c.edwards]]

The bellow code attempts to use LoadStringA() to initialize _buf. 
However, regardless of what form _buf takes, the body of the if 
statement is always executed. I've attempted to use every type of string 
available in D to include char* _buf[MAX_RESSTRING+1] and setting 
_buf[MAX_RESSTRING] = '\0'; What am I doing incorrectly?
Any assistance is greatly appreciated.

class ResString
{
  enum { MAX_RESSTRING = 255 }
        
  alias getBuffer this;
  @property string getBuffer() { return _buf; }
  this(HINSTANCE hInst, int resId)
  {
    _buf.length = MAX_RESSTRING;
        
    SetLastError(0);
                
    if(!LoadStringA(hInst, resId, cast(char*)toStringz(_buf), 
_buf.length + 1))
    {
      throw new WinException("Load String failed");
    }
  }

private:
  string _buf;
}