How to set DataGridView Rows FontStyle with condition at loading time?

How to change the Font Style of all Rows of a DataGridView based on a conditions?

My condition is if Cell Value Equal 0 then FontStyle = Strikeout otherwise Regular

Private Function DetailGridViewSetStyle()
    Dim dgv As DataGridView = DetailDataGridView
    Dim dgvInd As Integer = dgv.CurrentRow.Index
   
    For cc As Integer = 0 To dgv.ColumnCount - 1
        If dgv.Item(4, dgvInd).Value = 0 Then
            dgv.DefaultCellStyle.Font = New Font("ARIAL", 8, FontStyle.Strikeout)
        ElseIf dgv.Item(4, dgvInd).Value = 1 Then
            dgv.DefaultCellStyle.Font = New Font("ARIAL", 8, FontStyle.Regular)
        End If
    Next
End Function

• Only use "Function" if you need to return something, that's not your case, use Sub instead.
• dgv.DefaultCellStyle.Font will set font style for all your datagrid, you need to set font style from a specify row, then use row.DefaultCellStyle.Font

If I understood your question, here's the code that you need:

Private Sub DetailGridViewSetStyle()
        Dim dgv As DataGridView = DetailDataGridView

        For Each row As DataGridViewRow In dgv.Rows
            Dim Value As Boolean = CBool(row.Cells(4).Value)

            If Value = False Then
                row.DefaultCellStyle.Font = New Font("ARIAL", 8, FontStyle.Strikeout)
            Else
                row.DefaultCellStyle.Font = New Font("ARIAL", 8, FontStyle.Regular)
            End If

        Next
    End Sub