运营商和放大器;＆安培;不能应用 [英] Operator && cannot be applied

问题描述

我测试的例子片段，我发现作为<一个答案href="http://stackoverflow.com/questions/3920551/permission-deny-mask-in-sharepoint/4320497#4320497">another问

I am testing an example snippet that I found as an answer on another Question

但是编译器吐出这种运营商和放大器;＆功放;不能应用于类型为长和布尔操作数。 它为什么要这样做呢？当我读了code，它说：如果面具和权限大于0成功返回布尔

However the compiler is spitting out this "Operator && cannot be applied to operands of type long and bool". Why does it do this? As I read the code, it says "If mask and permission are greater than 0 return success bool"

我是读这错了吗？

（同样，没有人叫出来一个坏榜样，所以我希望它的工作。这并不是说我是一个复制粘贴codeR）

(Also, no one called it out as a bad example so I expected it to work. Not that I am a copy-paste coder)

bool CheckMask( long Mask, long TestPermission ) {
    return Mask && TestPermission > 0;
}

long mask = 4611686844973976575;

const long MASK_ViewListItems = 0x0000000000000001;
bool HasPermission_ViewListItems = CheckMask(mask, MASK_ViewListItems);
// HasPermission_ViewListItems is true

const long MASK_UseClientIntegration = 0x0000001000000000;
bool HasPermission_UseClientIntegration = CheckMask(mask, MASK_UseClientIntegration);
// HasPermission_UseClientIntegration is false

有非常多的关于StackOverflow的类似的问题，我已经点击过大部分，有一个大的名单给我的权利，我打字。无已应用到我的情况，至少我能看到的答案，我的问题之间的关系。

There are an awful lot of similar questions on StackOverflow and I've clicked through most of them, there's a big list to my right as I type. None have applied to my situation, at least I was able to see the relation between the answers and my problem.

推荐答案

您正在使用的 ＆功放;＆安培; （有条件的，仅适用于布尔操作数），而不是<一 HREF =htt​​p://msdn.microsoft.com/en-us/library/sbf85k1c.aspx相对=nofollow> ＆安培; （按位与，有效期布尔操作数或整数操作数） - 我怀疑你希望是后者，你也应该使用因precedence规则支架。我想改变参数的名称遵循.NET命名约定，太 - 并使其静态的，因为它不依赖于任何状态：

You're using && (conditional AND, only valid for bool operands) instead of & (bitwise AND, valid for bool operands or integer operands) - I suspect you want the latter, and you should also use brackets due to precedence rules. I'd change the parameter names to follow .NET naming conventions, too - and make it static as it doesn't rely on any state:

static bool CheckMask(long mask, long testPermission)
{
    return (mask & testPermission) > 0;
}

您可能还需要更改为使用的枚举，而不是长：

You might also want to change to using an enum instead of long:

[Flags]
public enum Permissions
{
    ViewListItems = 1 << 0,
    ...
    UseClientIntegration = 1 << 9
}

static bool CheckMask(Permissions mask, Permissions testPermission)
{
    return (mask & testPermission) != 0;
}

这篇关于运营商和放大器;＆安培;不能应用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！