检查是否没有 [英] Check if is nothing

问题描述

您好，


我有以下内容：

如果MyTag什么都没有那么

...

结束如果


我收到错误。


MyTag的类型为HtmlTextWriterTag


私人MyTag作为HtmlTextWriterTag


我如何检查是否给了MyTag一个值？


谢谢，
Miguel

Hello,

I have the following:
If MyTag Is Nothing Then
...
End If

I am getting an error.

MyTag is of type HtmlTextWriterTag

Private MyTag As HtmlTextWriterTag

How can I check if a value was given to MyTag or not?

Thanks,
Miguel

推荐答案

如果IsNothing（MyTag）那么

。 。 。

结束如果


" shapper" < md ***** @ gmail.com写信息

新闻：11 ********************** @ u30g2000hsc。 googlegr oups.com ...

If IsNothing(MyTag) Then
. . .
End If

"shapper" <md*****@gmail.comwrote in message
news:11**********************@u30g2000hsc.googlegr oups.com...

您好，


我有以下内容：

如果MyTag什么都没有那么

...

结束如果


我收到错误。


MyTag的类型为HtmlTextWriterTag


私有MyTag为HtmlTextWriterTag


如何检查MyTag是否有值是不是？


谢谢，

Miguel

Hello,

I have the following:
If MyTag Is Nothing Then
...
End If

I am getting an error.

MyTag is of type HtmlTextWriterTag

Private MyTag As HtmlTextWriterTag

How can I check if a value was given to MyTag or not?

Thanks,
Miguel

使用x =无对于值类型和x Is Nothing对于引用类型。

如果将x设置为默认值，则返回true。 （另外一个

复杂功能是你可以同时使用两个字符串，但这是另一天

的故事。）

-

David Anton
www.tangiblesoftwaresolutions.com

即时C＃：VB到C＃转换器

即时VB：C＃到VB转换器

C ++到C＃转换器：将C ++转换为C＃

即时C ++：将C＃或VB转换为C ++ / CLI

" shapper"写道：

Use "x = Nothing" for value types and "x Is Nothing" for reference types.
This will return true if x is set to it''s default value. (a further
complication is that you can use both for strings, but that''s a story for
another day).
--
David Anton
www.tangiblesoftwaresolutions.com
Instant C#: VB to C# converter
Instant VB: C# to VB converter
C++ to C# Converter: converts C++ to C#
Instant C++: converts C# or VB to C++/CLI
"shapper" wrote:

您好，


我有以下内容：

如果MyTag什么都没有那么

...

结束如果


我收到错误。


MyTag的类型为HtmlTextWriterTag


Private MyTag As HtmlTextWriterTag


我如何检查是否给了MyTag一个值？


谢谢，

Miguel

Hello,

I have the following:
If MyTag Is Nothing Then
...
End If

I am getting an error.

MyTag is of type HtmlTextWriterTag

Private MyTag As HtmlTextWriterTag

How can I check if a value was given to MyTag or not?

Thanks,
Miguel

那只是另一个形式为MyTag Is Nothing，不值得为价值工作

类型。

-

David Anton www.tangiblesoftwaresolutions.com

即时C＃：VB到C＃转换器

即时VB：C＃到VB转换器

C ++到C＃转换器：将C ++转换为C＃

即时C ++：将C＃或VB转换为C ++ / CLI

" Scott M."写道：

That''s just another form of "MyTag Is Nothing", which won''t work for value
types.
--
David Anton
www.tangiblesoftwaresolutions.com
Instant C#: VB to C# converter
Instant VB: C# to VB converter
C++ to C# Converter: converts C++ to C#
Instant C++: converts C# or VB to C++/CLI
"Scott M." wrote:

如果IsNothing（MyTag）那么

。 。 。

结束如果


" shapper" < md ***** @ gmail.com写信息

新闻：11 ********************** @ u30g2000hsc。 googlegr oups.com ...

If IsNothing(MyTag) Then
. . .
End If

"shapper" <md*****@gmail.comwrote in message
news:11**********************@u30g2000hsc.googlegr oups.com...

您好，


我有以下内容：

如果MyTag什么都没有那么

...

结束如果


我收到错误。


MyTag的类型为HtmlTextWriterTag


私有MyTag为HtmlTextWriterTag


如何检查MyTag是否有值是不是？


谢谢，

Miguel

Hello,

I have the following:
If MyTag Is Nothing Then
...
End If

I am getting an error.

MyTag is of type HtmlTextWriterTag

Private MyTag As HtmlTextWriterTag

How can I check if a value was given to MyTag or not?

Thanks,
Miguel

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