calculate location on additional Textbox on each button click

Question

Im working on adding a group of textbox each time a button is clicked, but the position of the next group of textbox should refer on the previously created textbox.

here is the screencap.

this is the first image before clicking the 'more' button

next is after clicking the more button once.

but after clicking again the more button. the space between each textbox is too far from the other.

I know something is wrong in my location code. can someone help me check this.

Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles addbox.Click

    Dim Count = gbox2.Controls.OfType(Of TextBox)().ToList().Count

    For i As Integer = 1 To 6
        Dim txtbox As New TextBox()
        Select Case i
            Case 1
                txtbox.Location = New System.Drawing.Point(17, 30 * Count)
                txtbox.Size = New System.Drawing.Size(43, 26)
                txtbox.Name = "itemno2" & (Count + 1)
                gbox2.Controls.Add(txtbox)

            Case 2
                txtbox.Location = New System.Drawing.Point(81, 30 * Count)
                txtbox.Size = New System.Drawing.Size(43, 26)
                txtbox.Name = "unit2" & (Count + 1)
                gbox2.Controls.Add(txtbox)

            Case 3
                txtbox.Location = New System.Drawing.Point(142, 30 * Count)
                txtbox.Size = New System.Drawing.Size(254, 26)
                txtbox.Name = "itemdesc2" & (Count + 1)
                gbox2.Controls.Add(txtbox)

            Case 4
                txtbox.Location = New System.Drawing.Point(417, 30 * Count)
                txtbox.Size = New System.Drawing.Size(56, 26)
                txtbox.Name = "requan2" & (Count + 1)
                gbox2.Controls.Add(txtbox)

            Case 5
                txtbox.Location = New System.Drawing.Point(21, 30 * Count)
                txtbox.Size = New System.Drawing.Size(56, 26)
                txtbox.Name = "issuequan2" & (Count + 1)
                gbox3.Controls.Add(txtbox)

            Case 6
                txtbox.Location = New System.Drawing.Point(94, 30 * Count)
                txtbox.Size = New System.Drawing.Size(144, 26)
                txtbox.Name = "remarks2" & (Count + 1)
                gbox3.Controls.Add(txtbox)

        End Select

    Next
    'addbox.Visible = False
    save.Visible = False
End Sub

any help will be much appreciated. thanks in advance.

Answer 1

Use right tool for the job - DataGridView Control

Instead of calculating positions and adding textboxes you can just add a row in DataGridView.
You can use two DataGridView controls for "Requisition" and for "Issuance" groups.

In the designer create two DataGridView and add columns you need. Then in button click eventhandler you will add new row for both

Private Sub Button1_Click_1(sender As Object, e As EventArgs) Handles addbox.Click
    RequisitionDataGridView.Rows.Add(new object[] {value1, value2, value2 })
    IssuanceDataGridView.Rows.Add(new object[] {value6, value7})
End Sub

If you go further you can use DataSource property.
Create a class which represent one row of your data

Public Class Requisition
    Public Property ItemNo As Integer
    Public Property Unit As String
    Public ItemDescription As String
    Public Quantity As Decimal
End Class

Then create a BindingList(Of Requsition) and add it as data source in the DataGridiView

Public Class YourForm Inherits Form
    Private _requsitionData As New BindingList(Of Requsition)
    Private _issuanceData As New BindingList(Of Issuance) 

    Public Sub New()
        InitializeComponents()

        RequisitionDataGridView.DataSource = _requsitionData
        IssuanceDataGridView.DataSource = _issuanceData
    End Sub

    Private Sub Button1_Click_1(sender As Object, e As EventArgs) Handles addbox.Click
        _requsitionData.Add(new Requisition())
        _issuanceData.Add(new Issuance())
    End Sub       

End Class

Answer 2

Dim currentTop As Integer = 5
Dim defaultHeight As Integer = 26

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim Count = gbox2.Controls.OfType(Of TextBox)().ToList().Count

    currentTop += defaultHeight + 5

    For i As Integer = 1 To 6
        Dim txtbox As New TextBox()
        Select Case i
            Case 1
                txtbox.Location = New System.Drawing.Point(17, currentTop)
                txtbox.Size = New System.Drawing.Size(43, 26)
                txtbox.Name = "itemno2" & (Count + 1)
                gbox2.Controls.Add(txtbox)

            Case 2
                txtbox.Location = New System.Drawing.Point(81, currentTop)
                txtbox.Size = New System.Drawing.Size(43, 26)
                txtbox.Name = "unit2" & (Count + 1)
                gbox2.Controls.Add(txtbox)

            Case 3
                txtbox.Location = New System.Drawing.Point(142, currentTop)
                txtbox.Size = New System.Drawing.Size(254, 26)
                txtbox.Name = "itemdesc2" & (Count + 1)
                gbox2.Controls.Add(txtbox)

            Case 4
                txtbox.Location = New System.Drawing.Point(417, currentTop)
                txtbox.Size = New System.Drawing.Size(56, 26)
                txtbox.Name = "requan2" & (Count + 1)
                gbox2.Controls.Add(txtbox)

            Case 5
                txtbox.Location = New System.Drawing.Point(21, currentTop)
                txtbox.Size = New System.Drawing.Size(56, 26)
                txtbox.Name = "issuequan2" & (Count + 1)
                gbox3.Controls.Add(txtbox)

            Case 6
                txtbox.Location = New System.Drawing.Point(94, currentTop)
                txtbox.Size = New System.Drawing.Size(144, 26)
                txtbox.Name = "remarks2" & (Count + 1)
                gbox3.Controls.Add(txtbox)

        End Select

    Next
End Sub