语法问题 [英] Syntax Question

问题描述

我正在努力工作的公司正在尝试使用Microsoft发布的应用程序

数据块，以便为我们的.NET应用程序提供透明的数据库和b $ b连接。我的任务是完全理解代码。

。然而，当我浏览源代码时，我遇到了一段对我来说没有意义的代码

。我希望这里的某个人能够启发我。

有问题的代码在SqlDbHelper.vb文件中，位于

DiscoverSpParameterSet函数下：


Dim cn As New SqlConnection（connectionString）

Dim cmd As SqlCommand = New SqlCommand（spName，cn）

Dim discoveredParameters（）As IDataParameter


尝试

cn.Open（）

cmd.CommandType = CommandType.StoredProcedure

SqlCommandBuilder.DeriveParameters（cmd）

如果不是includeReturnValueParameter那么

cmd.Parameters.RemoveAt（0）

结束如果


discoveredParameters = New SqlParameter（cmd.Parameters.Count - 1）

{}

cmd.Parameters.CopyTo（discoveredParameters，0）

最后

cmd.Dispose（）

cn.Dispose（）

结束尝试


我不理解的一行是：


discoveredParameters =新的SqlParameter（cmd.Parameters.Count - 1）{}


我可以看到正在创建一个SqlParameter对象的实例。

但是，没有任何重载的构造函数匹配参数

给出。虽然在声明的最后是一个开始和结束

大括号（{}）。如果删除它，我确实得到了我刚才提到的预期的

错误。然而，有了这些花括号，

一切都很好。这里有什么成就？提前致谢

您可以提供的任何见解。


Robert

解决方案

< blockquote>" Robert Brinson" < RB ****** @ cox-internet.com> schrieb

我不理解的是：

discoveredParameters = New SqlParameter（cmd.Parameters.Count - 1）
{}
参数。虽然在声明的最后是一个开头
和结束大括号（{}）。如果删除它，我确实得到了我刚才提到的
预期错误。但是，有了这些卷曲的支撑，一切都很好。这里有什么成就？提前感谢您提供的任何见解。

我（也）认为这是语言不一致：


' '创建< type>的新实例，传递< args>到了ocnstructor。

var = New< type>（< args>）

''创建一个< type>的*数组*，上限是< args>，没有物品放入



数组：

var = new< type>（< args>）{}


''创建一个< typeY的*数组*，上限是< args>，一个项目放在
$ b $中b数组：

var = new< type>（< args>）{< Item>}


-

Armin

http：//www.plig .net / nnq / nquote.html
http： //www.netmeister.org/news/learn2quote.html

嗨罗伯特，


我等了Armin，因为他上周长时间争论这个空字符串

。


但如果我是你，我确实把这条消息也放了它在t他/ b
public.dotnet.framework.adonet新闻组。


许多活跃在该新闻组中的人特别知道来自

参数，较少受VB.language影响的人使用。


然后从2个方向的答案我认为你有最好的回应。


Cor

*" Armin Zingler" < AZ ******* @ freenet.de> scripsit：

我可以看到正在创建一个SqlParameter对象的实例。但是，重载的构造函数都不匹配给定的
参数。虽然在声明的最后是一个开头
和结束大括号（{}）。如果删除它，我确实得到了我刚才提到的
预期错误。但是，有了这些卷曲的支撑，一切都很好。这里有什么成就？提前感谢您提供的任何见解。
我（也）认为这是语言不一致：

请指出什么' '不一致'行为......

''创建< type>的新实例，传递< args>对于构造函数。
var = New< type>（< args>）
''创建< type>的*数组*，上限是< args>，
数组中没有任何项目：
var = new< type>（< args>）{}
''''创建一个*数组* of< typeY，上限是< args> ;,一个项目放在
数组中：
var = new< type>（< args>）{< Item>}

-

Herfried K. Wagner [MVP]

< http://www.mvps.org / dotnet>

The company I am working for is trying to work with the Application
Data Blocks that Microsoft released to provide transparent database
connectivity for our .NET applications. I have been tasked with having
a thorough understanding of the code. However, while wading through
the source, I came across a section of code that does not make sense
to me. I was hoping that someone here would be able to enlighten me.
The code in question is in the SqlDbHelper.vb file and is under the
DiscoverSpParameterSet function:

Dim cn As New SqlConnection(connectionString)
Dim cmd As SqlCommand = New SqlCommand(spName, cn)
Dim discoveredParameters() As IDataParameter

Try
cn.Open()
cmd.CommandType = CommandType.StoredProcedure
SqlCommandBuilder.DeriveParameters(cmd)
If Not includeReturnValueParameter Then
cmd.Parameters.RemoveAt(0)
End If

discoveredParameters = New SqlParameter(cmd.Parameters.Count - 1)
{}
cmd.Parameters.CopyTo(discoveredParameters, 0)
Finally
cmd.Dispose()
cn.Dispose()
End Try

The line I am not understanding is:

discoveredParameters = New SqlParameter(cmd.Parameters.Count - 1) {}

I can see that an instance of a SqlParameter object is being created.
However, none of the overloaded constructors match the arguments
given. Though at the end of the statement are an opening and closing
curly brace ({}). If this is removed, I do indeed get the expected
error that I just mentioned. However, with these curly braces,
everything is fine. What is being accomplished here? Thanks in advance
for any insight you can provide.

Robert

解决方案

"Robert Brinson" <rb******@cox-internet.com> schrieb

The line I am not understanding is:

discoveredParameters = New SqlParameter(cmd.Parameters.Count - 1)
{}

I can see that an instance of a SqlParameter object is being
created. However, none of the overloaded constructors match the
arguments given. Though at the end of the statement are an opening
and closing curly brace ({}). If this is removed, I do indeed get the
expected error that I just mentioned. However, with these curly
braces, everything is fine. What is being accomplished here? Thanks
in advance for any insight you can provide.

I (also) think this is a language inconsistency:

''creates a new instance of <type>, passing <args> to the ocnstructor.
var = New <type>(<args>)

''creates an *array* of <type>, upper bound is <args>, no items are put in
the
array:
var = new <type>(<args>){}

''creates an *array* of <typeY, upper bound is <args>, one item is put in the
array:
var = new <type>(<args>){<Item>}

--
Armin

http://www.plig.net/nnq/nquote.html
http://www.netmeister.org/news/learn2quote.html

Hi Robert,

I waited on Armin, because he had a long arguing about this empty string
last week.

But if I was you I did put this message also it in the
public.dotnet.framework.adonet newsgroup.

A lot of those who are active in that newsgroup knows especialy much from
the parameters, which are less used by the more VB.language affected people.

Then with the answers from 2 directions I think you have the best response.

Cor

* "Armin Zingler" <az*******@freenet.de> scripsit:

I can see that an instance of a SqlParameter object is being
created. However, none of the overloaded constructors match the
arguments given. Though at the end of the statement are an opening
and closing curly brace ({}). If this is removed, I do indeed get the
expected error that I just mentioned. However, with these curly
braces, everything is fine. What is being accomplished here? Thanks
in advance for any insight you can provide.
I (also) think this is a language inconsistency:

Please point out what''s "inconsistent" behavior...
''creates a new instance of <type>, passing <args> to the ocnstructor.
var = New <type>(<args>)

''creates an *array* of <type>, upper bound is <args>, no items are put in
the
array:
var = new <type>(<args>){}

''creates an *array* of <typeY, upper bound is <args>, one item is put in the
array:
var = new <type>(<args>){<Item>}

--
Herfried K. Wagner [MVP]
<http://www.mvps.org/dotnet>

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