難以使用MembershipProvider.GetUserNameByEmail - 會不會編譯？

Question

我正在此錯誤：

一個對象引用是所必需的非靜態字段，方法或屬性「System.Web.Security.MembershipProvider.GetUserNameByEmail（字符串）

當試圖使用代碼：

string userName = MembershipProvider.GetUserNameByEmail(email); 

從我的控制器：

[HttpPost] 
public ActionResult ChangeEmail(ChangeEmailViewModel model) 
{ 
    if (ModelState.IsValid) 
    { 
     string email = model.Email; 
     string userName = MembershipProvider.GetUserNameByEmail(email); 
     if (userName != null) 
     { 
      // change email 
     } 
     else 
     { 
      // don't allow email change as that email is already in use 
     } 
    } 
} 

我不明白爲什麼我收到錯誤的我找到了這個代碼的例子，看不出有什麼不同？

Answer 1

嘗試Membership.GetUserNameByEmail(email)。