if(myFile.PostedFile!=null) then//据我所知,VB.NET对象为空的话叫Nothing不叫nulltry: if not myFile.PostedFile is Nothing then
改了這一句,if not myFile.PostedFile is Nothing then,可是當我點擊按鈕時,出現如下的錯誤:StartIndex cannot be less than zero. Parameter name: startIndex 這一行出錯:dim newnm as string =nam.Substring(i) 怎樣解決?
怎樣解決?