string 在VB.NET中修剪字符串的最后一个“，”分隔符
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Trim last "," delimiter of a string in VB.NET
提问by gerfe
This is my code:
这是我的代码：
With ad.Tables(2)
For i As Integer = 0 To .Rows.Count - 1
If .Rows(i)("name") & "" <> "" Then
temp &= .Rows(i)("name") & ", "
End If
Next
End With
temp = temp.Trim(",")
testing &= "&Name=" & temp & vbCrLf
With this is get a comma in the end of the string. But if I do
有了这个，在字符串的末尾得到一个逗号。但如果我这样做
temp = temp.Trim.Trim(",")
all commas are deleted.
删除所有逗号。
How do I keep all commas and only delete the last one?
如何保留所有逗号并只删除最后一个？
回答by Captain America
temp = temp.TrimEnd(CChar(","))
That will do it and I think it is the easiest way.
这样就可以了，我认为这是最简单的方法。
回答by Hans Olsson
temp = temp.Trim().Substring(0, temp.Length - 1)
or
或者
temp = temp.Trim().Remove(temp.Length - 1)
回答by Alex K.
You can avoid the Trim/extra character if you set a delimiter within the loop
如果在循环中设置分隔符，则可以避免使用 Trim/extra 字符
Dim delimiter as string = ""
For i As Integer = 0 To .Rows.Count - 1
If .Rows(i)("name") & "" <> "" Then
temp &= delimiter & .Rows(i)("name")
delimiter = ","
End If
Next
回答by SsJVasto
The Trim()function has a Char()(static array of characters) parameter on it, you don't need to pass a Charexplicitly.
该Trim()函数有一个Char()（静态字符数组）参数，您不需要Char显式传递 a 。
' VB.Net Version
", Hello ^_^ ^_^ ,,, , ,, ,, ,".Trim({" "c, ","c})
//C# version
", Hello ^_^ ^_^ ,,, , ,, ,, ,".Trim({' ', ','})
Would produce the output
会产生输出
"Hello ^_^ ^_^"
The multi-parameter .Trim()removes the specified characters from both the beginning and the end of the string. If you want to only trim out the beginning or the end, use .TrimStart()or .TrimEnd()respectively.
多参数.Trim()从字符串的开头和结尾删除指定的字符。如果您只想剪掉开头或结尾，请分别使用.TrimStart()或.TrimEnd()。
回答by One Day
This works:
这有效：
dim AlarmStr as string="aaa , bbb , ccc , "
AlarmStr = AlarmStr.Remove(AlarmStr.LastIndexOf(","))
回答by Robert Barrueco
Check to see if the loop is done before adding the last comma. #cleaner
在添加最后一个逗号之前检查循环是否完成。＃清洁工
While dr.Read
For c As Integer = 0 To dr.FieldCount - 1
s.Append(dr(c).ToString.Trim)
'This line checks if the loop is ending before adding a comma
If (c < dr.FieldCount - 1) Then s.Append(",")
Next
s.Append(vbCrLf)
End While
回答by Fabio
I wonder, that based on the OP's code sample, nobody suggested to use String.Joinor build an output with StringBuilder
我想知道，基于 OP 的代码示例，没有人建议使用String.Join或构建输出StringBuilder
Dim names As New List(Of String)
With ad.Tables(2)
For i As Integer = 0 To .Rows.Count - 1
' DataRow("columnName").ToString() returns value or empty string if value is DbNull
If .Rows(i)("name").ToString() <> "" Then
names.Add(.Rows(i)("name"))
End If
Next
End With
Dim temp As String = String.Join(", ", names)
testing &= "&Name=" & temp & vbCrLf
With LINQ and DataRowextension method .Field(Of T)code will look simpler
使用 LINQ 和DataRow扩展方法.Field(Of T)代码看起来更简单
Dim names = ad.Tables(2).
AsEnumerable().
Select(row => row.Field<String>("name")).
Where(name => String.IsNullOrEmpty(name) = False)
Dim temp As String = String.Join(", ", names)
testing &= "&Name=" & temp & vbCrLf
If you go further you can(should) use StringBuilderfor building a string and use Aggregatemethod to build string from the collection
如果您更进一步，您可以（应该）StringBuilder用于构建字符串并使用Aggregate方法从集合中构建字符串
回答by nghiavt
I know that a little bit odd, but I found this works for me:
我知道这有点奇怪，但我发现这对我有用：
Visual Basic:
视觉基础：
Every time: mystring = "today, I love go out , , , ," (less than five commas and spaces)
每次：mystring = "今天，我爱出去 , , , ," (少于五个逗号和空格)
mystring.Trim.TrimEnd(",").Trim.TrimEnd(",").Trim.TrimEnd(",").Trim.TrimEnd(",").Trim.TrimEnd(",")
回答by shradha
temp = temp.TrimEnd()
this trims the trailing spaces from a string.
这会修剪字符串的尾随空格。
