How to check if new line is empty in richtextbox - vb.net

Question

I am checking if a line in richtextbox is empty. If not, it will go at the next line.
The code I am using is:
Dim text as string="hello"
Dim lines = RichTextBox1.Lines
Dim upperBound = lines.GetUpperBound(0)
If lines(upperBound).Trim() = String.Empty Then
lines(upperBound) = text
RichTextBox1.Lines = lines
Else
RichTextBox1.AppendText(Environment.NewLine & text)
End If
Which is working perfectly. But just now I discovered that if Richtextbox1 is completely empty, this code will not add text to it. Is there any way to fix this little bug? Thanks

Answer 1

See if this does what you want:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text As String = "hello"
If RichTextBox1.Text.Trim = "" Then
RichTextBox1.AppendText(titolo)
ElseIf RichTextBox1.Lines(RichTextBox1.Lines.GetUpperBound(0)).Length = 0 Then
RichTextBox1.AppendText(titolo)
ElseIf RichTextBox1.Lines(RichTextBox1.Lines.GetUpperBound(0)).Trim = "" Then
Dim lines = RichTextBox1.Lines
lines(lines.GetUpperBound(0)) = titolo
RichTextBox1.Lines = lines
Else
RichTextBox1.AppendText(Environment.NewLine & text)
End If
End Sub

Answer 2

You can try this very efficient system.
This is called LinQ for array, You can query an array for a empty line,
if the count is greater than 0 then exit(or give an error)
Dim text As String = "hello"
Dim lines = RichTextBox1.Lines
Dim qry = From n In lines
Where n = ""
Select n
If qry.Count > 0 Then
'you can give some error here
End If

Answer 3

Try:
Dim text as string="hello"
Dim lines = RichTextBox1.Lines
Dim empty = {""}
If lines.Length = 0 Then lines = empty
Dim upperBound = lines.GetUpperBound(0)
If lines(upperBound).Trim() = String.Empty Then
lines(upperBound) = titolo
RichTextBox1.Lines = lines
Else
RichTextBox1.AppendText(Environment.NewLine & text)
End If