I am creating my data grid clomns dynamically. Each have different data type and precision value.

My Parameter class

 public class Parameter
        {

            public string ParameterName { get; set; }
            public double Value { get; set; }
            public Type Type { get; set; }
            public string Precision { get; set; }
        }

Colum initialization

 void xamDataGrid_FieldLayoutInitialized(object sender, Infragistics.Windows.DataPresenter.Events.FieldLayoutInitializedEventArgs e)
        {

            SpreadsheetViewModel.MyViewModel columns = this.ViewModel.Data.First();






            for (int i = 0; i < columns.Parameters.Count; i++)
            {
                var field = new UnboundField
                {
                    Name = columns.Parameters[i].ParameterName,
                    BindingMode = BindingMode.TwoWay,
                    DataType = columns.Parameters[i].Type,
                    Format = columns.Parameters[i].Precision,
                    BindingPath = new PropertyPath("Parameters[" + i + "].Value"),
                    AllowEdit = false,




                };

                field.Settings.EditAsType = typeof(String);
                e.FieldLayout.Fields.Add(field);


            }



        }

If I manually set DataType = typeof(double ) it has no problem, but when I send same thing though parameter  it gives an error

What might be the reason ?