Dynamic MVC Grid when we do not know the fields

Could you please be more specific?
If you're referring to how to add columns to a DataGridView where you don't know what the columns would be, it would look something like this;

private void Form1_Load(object sender, EventArgs e)
{
    try
    {
        DataGridViewColumn column;
        DataGridViewCell cell = new DataGridViewTextBoxCell();
        for (int i = 0; i < 5; i++)
        {
            column = new DataGridViewColumn();
            column.Name = "column" + (i+1).ToString();
            column.HeaderText = "Column " + (i+1).ToString();
            column.ValueType = typeof(string);
            
            column.CellTemplate = cell;

            dataGridView1.Columns.Add(column);
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

NOTE: If you're going to be adding columns dynamically, make sure the column doesn't already exist before trying to add it.