How to get rid of the first concatenation symbol - vb.net

Question

I'm looping a table database to catch the first name of some rows
The code is like:
Try
While (readerFirstName.Read())
SearchedName = readerFirstName("parteA")
CombinatedNames = CombinatedNames & " & " & SearchedName
End While
Catch ex As Exception
MsgBox(ex.ToString())
End Try
And the desired result si something like
Mike & Eric & Tom
but I get
& Mike & Eric & Tom
I think I can get rid of the first " &" after the string formation using String.TrimStart
but there's a better way to cut the first "& "?

Answer 1

Try replacing your loop:
While (readerFirstName.Read())
SearchedName = readerFirstName("parteA")
CombinatedNames = CombinatedNames & " & " & SearchedName
End While
With this one:
Dim names As New List(Of String)()
While (readerFirstName.Read())
names.Add(readerFirstName("parteA"))
End While
CombinatedNames = String.Join(" & ", names)
The main idea here is to use the String.Join method to concatenate the single names in one single operation. That method acts on collections, so you will first have to read the single items into a collection names.
This method will take care to add the separator string " & " between items, never before the first or after the last, so you will not end up with a leading or trailing separator (unless you have an empty item in your list).
P.S.: If you happen to know beforehand how many names will be read from readerFirstNames, you could optimise memory usage of my suggested code by passing the name count to the List(Of T) constructor (as the capacity parameter).

Answer 2

You can check the contains in combine string before adding text in it
While (readerFirstName.Read())
SearchedName = readerFirstName("parteA")
If Not isNullOrEmpty(CombinatedNames) Then
CombinatedNames = CombinatedNames & " & " & SearchedName
Else
CombinatedNames = SearchedName
End If
End While

Answer 3

The other answers are the usual way to do it, but here are few lazier alternatives:
this will remove the first 3 characters:
CombinatedNames = Mid( CombinatedNames , 4 )
this will trim and & from the beginning of the string:
CombinatedNames = CombinatedNames.TrimStart(" "c, "&"c)

Answer 4

or you can just read the first record and then concatenate the rest:
CombinatedNames = If(readerFirstName.Read, readerFirstName!parteA.ToString, "")
While readerFirstName.Read
CombinatedNames &= " & " & readerFirstName!parteA.ToString
End While