I have a Grid, some Fields in the Grid have custom validation which are set in the FieldLayout. For the beginning i will edit a cell, and set a new value for example -4   In the EditModeEnding EventHandler i check the value, but i couldn´t set the HasDataError  because it is a readonly property. 

What is the best way to validate a specific Field and color the background with a color ?
In the Feature Browser there is an example Data Error Styling, that is the behaviour which i will implement. But in the example the DataSource implements some interfaces and in my case, i have no DataSource which implements this interface.

XAML.

<my:Field Name="Name"  Label="Name">
</my:Field>

 <my:Field Name="value"  Label="value">
     </my:Field>

 <igDP:FieldLayoutSettings SupportDataErrorInfo="RecordsAndCells"
            DataErrorDisplayMode="ErrorIconAndHighlight" />

Codebehind:

void xamDataPresenter1_EditModeEnding(object sender, EditModeEndingEventArgs e)
        {
            if (e.Cell.Field.Label.Equals("man"))
            {
                int value;

                if (!Int32.TryParse(e.Editor.Text, out value))
                {
                    e.AcceptChanges = false;

                    string val = e.Cell.Value.ToString();

                    MessageBox.Show("Data Validation Failed. Must enter an Integer: " + val);

                    e.Cancel = true;
                }
                else
                {
                    if(value < 0)
                    {
                       // e.Cell.HasDataError    TODO !!! How to set this cell ??
                   
                        e.Cancel = true;

                       // TODO: assign this cell with a different style   -> RED Background 
e.Cell.DataPresenter.FieldSettings.CellValuePresenterStyle = GetLabelStyle(System.Windows.Media.Brushes.Red, true);             

} 

                    else
                    {          //assign different style   -> GREENBackground  

                     }

                }
            }
        }

The next step, how  to set the cell the Backgrounds programmatically (GREEN, RED)

In the examples i have seen a DataSource Class which implements the IDataErrorInfo. In my project we have Bound all Fields manually in the grid. i have no IDataErrorInfo implemented, because i haven´t got a BusinessClass. how to use this functionality without IDataErrorInfo in my project?