public partial class MainPage : ContentPage
{
    public MainPage()
    {
        InitializeComponent();        

        SfDataGrid sfDataGrid = new SfDataGrid
        {
            SortingMode = DataGridSortingMode.Single,
            AutoGenerateColumnsMode = AutoGenerateColumnsMode.None,
        };

        MyViewModel.Cols.ForEach(col => sfDataGrid.Columns.Add(new DataGridTextColumn
        {
            HeaderText = col,
            MappingName = $"{nameof(MyViewModel.Dico)}[{col}]",
            LoadUIView = false,
            Width = 100
        }));

        sfDataGrid.ItemsSource = Enumerable.Range(0, 100)
                                 .Select(i => new MyViewModel(i))
                                 .ToList();

        Content = sfDataGrid;
    }
}

public class MyViewModel
{
    public MyViewModel(int i)
    {
        Cols.ForEach(col => Dico[col] = $"Val_{col}_{i}");
    }
    public static List<string> Cols { get; } = new List<string>() { "Col1", "Col2", "Col3", };
    public Dictionary<string, string> Dico { get; set; } = new Dictionary<string, string>();
}