Ciao per impostare il valore di una colonna ,
ti conviene creare una Sub per formattare la tua datagrid che puoi richiamare sulla Load del form o quando vuoi .

Ti allego un esempio :
codice:
    
    Private Sub Formatta_GrdJobs_Anagrafica(ByVal V_Origine As Long)
        Dim StyleGrid As New DataGridTableStyle 
        GrdJob.TableStyles.Remove(StyleGrid)
        StyleGrid.MappingName = "Utenti.v_job_in_lavorazione"
        GrdJob.CaptionText = "ELENCO FILE IN LAVORAZIONE"

        Dim Col_File As New DataGridTextBoxColumn
        Col_File.MappingName = "Nome_File"
        Col_File.HeaderText = "File"
        Col_File.Width = 170
        Col_File.ReadOnly = True

        Dim Col_Utente As New DataGridTextBoxColumn
        Col_Utente.MappingName = "Utente"
        Col_Utente.HeaderText = "Utente"
        Col_Utente.Alignment = HorizontalAlignment.Center
        Col_Utente.ReadOnly = True
        Col_Utente.Width = 50

        Dim Col_Rk_Tot As New DataGridTextBoxColumn
        Col_Rk_Tot.MappingName = "totale_rk"
        Col_Rk_Tot.HeaderText = "Totale"
        Col_Rk_Tot.Alignment = HorizontalAlignment.Center
        Col_Rk_Tot.ReadOnly = True
        Col_Rk_Tot.Width = 50

        Dim Col_Rk_Lav As New DataGridTextBoxColumn
        Col_Rk_Lav.MappingName = "ultimo_rk"
        Col_Rk_Lav.HeaderText = "Lavorate"
        Col_Rk_Lav.Alignment = HorizontalAlignment.Center
        Col_Rk_Lav.ReadOnly = True
        Col_Rk_Lav.Width = 70

        Dim Col_Si_Match As New DataGridTextBoxColumn
        Col_Si_Match.MappingName = "si_match"
        Col_Si_Match.HeaderText = "S"
        Col_Si_Match.Alignment = HorizontalAlignment.Center
        Col_Si_Match.ReadOnly = True
        Col_Si_Match.Width = 50

        Dim Col_No_Match As New DataGridTextBoxColumn
        Col_No_Match.MappingName = "no_match"
        Col_No_Match.HeaderText = "N"
        Col_No_Match.Alignment = HorizontalAlignment.Center
        Col_No_Match.ReadOnly = True
        Col_No_Match.Width = 50

        Dim Col_Dubbi As New DataGridTextBoxColumn
        Col_Dubbi.MappingName = "dubbi"
        Col_Dubbi.HeaderText = "F"
        Col_Dubbi.Alignment = HorizontalAlignment.Center
        Col_Dubbi.ReadOnly = True
        Col_Dubbi.Width = 50

        Dim Col_Errati As New DataGridTextBoxColumn
        Col_Errati.MappingName = "match_errati"
        Col_Errati.HeaderText = "T"
        Col_Errati.Alignment = HorizontalAlignment.Center
        Col_Errati.ReadOnly = True
        Col_Errati.Width = 50

        Dim Col_Tempo As New DataGridTextBoxColumn
        Col_Tempo.MappingName = "Tempo"
        Col_Tempo.HeaderText = "Tempo"
        Col_Tempo.Alignment = HorizontalAlignment.Center
        Col_Tempo.ReadOnly = True
        Col_Tempo.Width = 80

        Dim Col_Perc_Si As New DataGridTextBoxColumn
        Col_Perc_Si.MappingName = "perc_si"
        Col_Perc_Si.HeaderText = "% S"
        Col_Perc_Si.Alignment = HorizontalAlignment.Center
        Col_Perc_Si.Format = "##0.00"
        Col_Perc_Si.ReadOnly = True
        Col_Perc_Si.Width = 40

        Dim Col_Match_Ora As New DataGridTextBoxColumn
        Col_Match_Ora.MappingName = "match_orari"
        Col_Match_Ora.HeaderText = "Match/Ora"
        Col_Match_Ora.Alignment = HorizontalAlignment.Center
        Col_Match_Ora.Format = "##0"
        Col_Match_Ora.ReadOnly = True
        Col_Match_Ora.Width = 70

        StyleGrid.GridColumnStyles.Add(Col_File)
        StyleGrid.GridColumnStyles.Add(Col_Utente)
        StyleGrid.GridColumnStyles.Add(Col_Perc_Si)
        StyleGrid.GridColumnStyles.Add(Col_Match_Ora)
        StyleGrid.GridColumnStyles.Add(Col_Rk_Tot)
        StyleGrid.GridColumnStyles.Add(Col_Rk_Lav)
        StyleGrid.GridColumnStyles.Add(Col_Si_Match)
        StyleGrid.GridColumnStyles.Add(Col_No_Match)
        StyleGrid.GridColumnStyles.Add(Col_Dubbi)
        StyleGrid.GridColumnStyles.Add(Col_Errati)
        StyleGrid.GridColumnStyles.Add(Col_Tempo)
        StyleGrid.BackColor = Color.WhiteSmoke
        StyleGrid.AlternatingBackColor = Color.LightGray
        StyleGrid.GridLineStyle = DataGridLineStyle.Solid
        GrdJob.TableStyles.Add(StyleGrid)
    End Sub
Ciao Rex