VB.net Import .txt file to pre existing columns in Datagridview

first to me: I'm fairly new in vb.net and still a beginner and reading many many guides/articles to improve myself but sadly I can't get over this problem.

I have a Form with data gridview and set the Columns in my Text:

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    table.Columns.Add("ID", Type.GetType("System.String"))
    table.Columns.Add("First Name", Type.GetType("System.String"))
    table.Columns.Add("Last Name", Type.GetType("System.String"))
    table.Columns.Add("Age", Type.GetType("System.String"))

    DataGridView1.DataSource = table

End Sub

Now I want to import the text from a Text.File which I already created: (it was created with the exact method like this one but not imported it was exported) The text file looks like this:

1|a|a|a

2|b|b|b

3|c|c|c

To import the Textfile:

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim lines() As String
        Dim vals() As String

        lines = File.ReadAllLines("C:\Users\duidi\Desktop\Test\log3.txt")



        For i As Integer = 0 To lines.Length - 1 Step +1
            vals = lines(i).ToString().Split("|")
            Dim row(vals.Length - 1) As String
            For j As Integer = 0 To vals.Length - 1 Step +1
                row(j) = vals(j).Trim()

            Next j
            table.Rows.Add(row)
        Next i

    End Sub

To my Problems:

I want to change the width of the columns (maybe something else too like font, height) but I have absolutely no clue how to edit the width of the columns while they are in a datatable.

I could add the columns via Form.Designer and change the width there but than I have no clue how to get the connections between datatable and columns.

What is the actual purpose of this program:

I want to export the data from a dataviewgrid (maybe encrypt it (later point)) than import the data in the exact same datagridview edit it and export again. And so on.

I know there are many, many posts out there which describe the import/export to .txt file but I am still too new to adapt it on my own to my program, I need to see the solution on my own text. I could really need your help!

Sorry for my bad English I am not a native

Here is my full (functional) code

Imports System.IO

Public Class Form1
    Dim table As New DataTable("Table")
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        table.Columns.Add("ID", Type.GetType("System.String"))
        table.Columns.Add("First Name", Type.GetType("System.String"))
        table.Columns.Add("Last Name", Type.GetType("System.String"))
        table.Columns.Add("Age", Type.GetType("System.String"))

        DataGridView1.DataSource = table
    End Sub

    Private Sub btn_export_Click(sender As Object, e As EventArgs) Handles btn_export.Click
        Dim writer As TextWriter = New StreamWriter("C:\Users\duidi\Desktop\Test\log.txt")

        For i As Integer = 0 To DataGridView1.Rows.Count - 2 Step +1
            For j As Integer = 0 To DataGridView1.Columns.Count - 1 Step +1

                If j = DataGridView1.Columns.Count - 1 Then
                    writer.Write(DataGridView1.Rows(i).Cells(j).Value.ToString())

                Else
                    writer.Write(DataGridView1.Rows(i).Cells(j).Value.ToString() & "|")
                End If

            Next j

            writer.WriteLine("")

        Next i
        writer.Close()
        MessageBox.Show("export fertig")


    End Sub

    Private Sub btn_import_Click(sender As Object, e As EventArgs) Handles btn_import.Click
        Dim lines() As String
        Dim vals() As String
        table.Clear()


        lines = File.ReadAllLines("C:\Users\duidi\Desktop\Test\log.txt")



        For i As Integer = 0 To lines.Length - 1 Step +1
            vals = lines(i).ToString().Split("|")
            Dim row(vals.Length - 1) As String
            For j As Integer = 0 To vals.Length - 1 Step +1
                row(j) = vals(j).Trim()

            Next j
            table.Rows.Add(row)
        Next i

    End Sub
End Class

Access to columns and styles:

Dim columnIndex = 0
Dim column = DataGridView1.Columns(columnIndex)

column.Width = 100

column.HeaderCell.Style = New DataGridViewCellStyle With {
    .Font = New Font("Times New Roman", 20, FontStyle.Bold),
    .Alignment = DataGridViewContentAlignment.MiddleCenter
}

column.DefaultCellStyle = New DataGridViewCellStyle With {
    .Font = New Font("Arial", 8, FontStyle.Italic),
    .Alignment = DataGridViewContentAlignment.MiddleRight
}

Here is the style documentation

What are your import problems? It is not clear from the question.

What is table object?