DataGridView1.RowHeaders.Width=200

Public Class Form1
 
    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) _
      Handles MyBase.Load
        Dim dt As New DataTable
 
        With dt
            .Columns.Add("Vorname")
            .Columns.Add("Nachname")
            .Rows.Add("Peter", "Zar")
            .Rows.Add("Paul", "Breitner")
            .Rows.Add("Karl", "Müller")
        End With
 
        DataGridView1.DataSource = dt
 
 
    End Sub
 
    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) _
      Handles Button1.Click
        DataGridView1.RowHeadersWidth = 200
    End Sub
End Class

EALA FREYA FRESENA