Question

Is there any difference between & and + operators while concatenating string? if yes, then what is difference? And if No, then why below code generating exception?

例:

    Dim s, s1, t As String
    Dim i As Integer

    s1 = "Hello"
    i = 1

    s = s1 & i
    t = s1 + i  //Exception here

    If s = t Then
        MessageBox.Show("Equal...")
    End If

Answer 1

以及 + 是二类操作者,但当你在使用+时指出一种分类时,即设法将“Hello”投入分类,添加。如果你将“Hello”改为“123”,你将获得结果124。

Answer 2

& is only used for string concatenation.
+ is overloaded to do both string concatenation and arithmetic addition.

<代码>+<>>/代码”的双重目的造成了混乱,与你的问题完全一样。特别是当<代码>Option Strict>时,因为汇编者将在你的笔迹和笔录中添加含蓄的文字,试图使你的代码具有意义。

我的建议

You should definitely turn Option Strict On, then the compiler will force you to add explicit casts where it thinks they are necessary.
You should avoid using + for concatenation because of the ambiguity with arithmetic addition.

这些建议也载于Microsoft Press book 。 BB和C#实用准则和最佳做法(第1.16、21.2节)

Answer 3

你也许会转而选择Strict(这是一件好事),汇编者告诉你,你可以做些补充。为此:

<代码>t = s1 & i.ToString(

Answer 4

如你的问题所证实,它们是不同的:& is ONLY string concatenation,+,上载的既有正常的添加,也有分类。

例如:

由于<代码>+的歌剧之一,是VB企图将脚ing改成愤怒,而你的扼杀不是数字;
。仅与胎体合作,使 in化转化为扼杀。

Answer 5

您可以撰写和复制;增加插播和编造:

processDetails=objProcess.ProcessId & ":" & objProcess.name
message = msgbox(processDetails,16,"Details")

产出如下:

5577:wscript.exe

Answer 6

Try this. It almost seemed to simple to be right. Simply convert the Integer to a string. Then you can use the method below or concatenate.

Dim I, J, K, L As Integer
Dim K1, L1 As String

K1 = K
L1 = L
Cells(2, 1) = K1 & " - uploaded"
Cells(3, 1) = L1 & " - expanded"

MsgBox "records uploaded " & K & " records expanded " & L

Answer 7

从以前的扼杀组合(分机)来看,你应当真正考虑使用“强令”。格式而不是分类。

    Dim s1 As String
    Dim i As Integer
    s1 = "Hello"
    i = 1
    String.Format("{0} {1}", s1, i)

它使事情更容易阅读和维护,我认为你的法典更加专业。见:code better - use string。格式。虽然并非每个人都同意。最好使用强硬。格式与说明分类?

Answer 8

我的两点:

如果你策划了大量的扼杀,那么你就应当使用“StingBuilder”。海事组织更清洁,大大faster。

友情链接