You can save or cancel the DataObject in Xamarin.Forms SfDataForm by storing the dataobject.
You can refer the following article.
C#
Raise the property change event to store the DataObject.
private void DataForm_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
    if(e.PropertyName == "DataObject")
    formModel = dataForm.DataObject as DataFormModel;
}C#
Cancel will reset the DataObject with stored dataobject.
private void OnCancel(object sender, EventArgs e)
{
    dataForm.DataObject = formModel;
    foreach (var property in dataForm.DataObject.GetType().GetProperties())
    {
        dataForm.UpdateEditor(property.Name);
    }
}C#
Saves the edited data by using Commit method.
private void OnSaved(object sender, EventArgs e)
{
    dataForm.Validate();
    dataForm.Commit();
    formModel = dataForm.DataObject as DataFormModel;
}