Thanks!!

You could either iterate through the Fields in the layout and set the Width or set it directly in the FieldSettings:

//First way

foreach (Field f in xdg1.DefaultFieldLayout.Fields)

{

f.Width = FieldLength.InitialAuto;

}

//Second way

xdg1.FieldSettings.Width = FieldLength.InitialAuto;

Let me know if you have any questions with this matter.

Thanks, but how can i set this, when the Grid is generate automatically (AutoGenerateFields)

In the XAML code are no Fields defined.