如何在C＃中检查未定义的值/对象 [英] How to check for Undefined Values/Objects in C#

问题描述

我需要检查C＃中未定义的值和对象，我应该使用哪个函数
。 （== null）对未定义的对象不起作用。


感谢

解决方案

" =？ UTF-8乙TS4gVXBwYWw = ="？？？？; < MU **** @ discussions.microsoft.com>写在

新闻：54 ********************************** @ microsof t .com：

我需要检查C＃中的未定义值和对象，我应该使用哪个函数。 （== null）不适用于未定义的对象。

Null未定义。我只发现了很少的例子，由于转换

或覆盖，因此无法在C＃中工作。

-

Chad Z .Hower（又名Kudzu） - http://www.hower.org/Kudzu/

编程是一种反击的艺术形式


使用IntraWeb支持ASP.NET
http://www.atozed.com/IntraWeb/

这是我的代码snipet不起作用

if（sObject [0] == null）{sLen =" 0";} else {sLen =

sObject.Length.ToString（）;}


其中sObject [0]的值为< undefined value>


怎么回事？我做了这个工作。


谢谢，


M. Uppal


" Chad Z Hower aka Kudzu"写道：

" =？Utf-8？B？TS4gVXBwYWw =？=" < MU **** @ discussions.microsoft.com>在
新闻中写道：54 ********************************** @ microsof t.com：< blockquote class =post_quotes>我需要检查C＃中的未定义值和对象，我应该使用哪个函数。 （== null）对未定义的对象不起作用。

Null未定义。我只发现了很少的例子，因为转换
或覆盖而无法在C＃中工作。

-
Chad Z. Hower（又名Kudzu） - < a rel =nofollowhref =http://www.hower.org/Kudzu/target =_ blank> http://www.hower.org/Kudzu/
编程是一种艺术形式，反击

Empower ASP.NET with IntraWeb
http://www.atozed.com/IntraWeb/

" =？Utf-8？B ？TS4gVXBwYWw = =" < MU **** @ discussions.microsoft.com>写在

新闻：EB ********************************** @ microsof t .com：

这是我的代码snipet不起作用
if（sObject [0] == null）{sLen =" 0" ;;} else {sLen =
sObject.Length.ToString（）;}

它的sObject [0]可能不是null，而是sObject本身。试试这个：


if（sObject == null）{sLen =" 0" ;; } ...


-

-mdb

Hi, I need to check for undefined values and objects in C#, which function
should i use. (== null) does not work for undefined objects.

thanks

解决方案

"=?Utf-8?B?TS4gVXBwYWw=?=" <MU****@discussions.microsoft.com> wrote in
news:54**********************************@microsof t.com:

Hi, I need to check for undefined values and objects in C#, which
function should i use. (== null) does not work for undefined objects.

Null is undefined. I''ve only found a very few instances that ti doesnt work in C# due to conversions
or overrides.
--
Chad Z. Hower (a.k.a. Kudzu) - http://www.hower.org/Kudzu/
"Programming is an art form that fights back"

Empower ASP.NET with IntraWeb
http://www.atozed.com/IntraWeb/

Here is my snipet of code that doesnot work
if (sObject[0] == null) {sLen = "0";} else {sLen =
sObject.Length.ToString();}

where sObject[0] has value of <undefined value>

how else should i make this work.

thanks,

M. Uppal

"Chad Z. Hower aka Kudzu" wrote:

"=?Utf-8?B?TS4gVXBwYWw=?=" <MU****@discussions.microsoft.com> wrote in
news:54**********************************@microsof t.com:

Hi, I need to check for undefined values and objects in C#, which
function should i use. (== null) does not work for undefined objects.

Null is undefined. I''ve only found a very few instances that ti doesnt work in C# due to conversions
or overrides.
--
Chad Z. Hower (a.k.a. Kudzu) - http://www.hower.org/Kudzu/
"Programming is an art form that fights back"

Empower ASP.NET with IntraWeb
http://www.atozed.com/IntraWeb/

"=?Utf-8?B?TS4gVXBwYWw=?=" <MU****@discussions.microsoft.com> wrote in
news:EB**********************************@microsof t.com:

Here is my snipet of code that doesnot work
if (sObject[0] == null) {sLen = "0";} else {sLen =
sObject.Length.ToString();}

Its probably not sObject[0] that is null, but sObject itself. Try this:

if (sObject == null) { sLen = "0"; } .....

--
-mdb

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