Vb.Net将StrDub转换为C#.net

我有这行代码:

strKey &= Strings.StrDup(intKeySize - intLength, chrKeyFill) 

C#中这段代码的等价物是什么? 我似乎无法找到它。

 strKey += new String(chrKeyFill, intKeySize - intLength); 

要么

 strKey = strKey.PadRight(intKeySize, chrKeyFill) 
 strKey += strKey.PadRight(strKey.Length + (intKeySize - intLength), chrKeyFill)