Trim last "," delimiter of a string in VB.NET - vb.net

Question

This is my code:
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
temp = temp.Trim.Trim(",")
all commas are deleted.
How do I keep all commas and only delete the last one?

Answer 1

temp = temp.TrimEnd(CChar(","))
That will do it and I think it is the easiest way.

Answer 2

temp = temp.Trim().Substring(0, temp.Length - 1)
or
temp = temp.Trim().Remove(temp.Length - 1)

Answer 3

You can avoid the Trim/extra character if you set a delimiter within the loop
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

Answer 4

The Trim() function has a Char() (static array of characters) parameter on it, you don't need to pass a Char explicitly.
' VB.Net Version
", Hello ^_^ ^_^ ,,, , ,, ,, ,".Trim({" "c, ","c})
//C# version
", Hello ^_^ ^_^ ,,, , ,, ,, ,".Trim({' ', ','})
Would produce the output
"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.

Answer 5

This works:
dim AlarmStr as string="aaa , bbb , ccc , "
AlarmStr = AlarmStr.Remove(AlarmStr.LastIndexOf(","))

Answer 6

Check to see if the loop is done before adding the last comma. #cleaner
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

Answer 7

I wonder, that based on the OP's code sample, nobody suggested to use String.Join or build an output with 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 DataRow extension method .Field(Of T) code will look simpler
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 StringBuilder for building a string and use Aggregate method to build string from the collection

Answer 8

I know that a little bit odd, but I found this works for me:
Visual Basic:
Every time: mystring = "today, I love go out , , , ," (less than five commas and spaces)
mystring.Trim.TrimEnd(",").Trim.TrimEnd(",").Trim.TrimEnd(",").Trim.TrimEnd(",").Trim.TrimEnd(",")

Answer 9

temp = temp.TrimEnd()
this trims the trailing spaces from a string.