Question

Hello guys i have collection :

public class ActionData
{
    private int iD;

    public int ID 
    {
        get { return iD; }
        set { iD = value; }
    }
    private string roomType;

    public string RoomType 
    {
        get { return roomType; }
        set { roomType = value; }
    }
}

like this

private void btnGridToExcel_Click(object sender, RoutedEventArgs e)
{
    ExportExcel<ActionData, ActionDatas> exp = new ExportExcel<ActionData, ActionDatas>();
    exp.GenerateReport();
    ICollectionView view = CollectionViewSource.GetDefaultView(dataGrid1.ItemsSource);
    exp.dataToPrint = (ActionDatas)view.SourceCollection;
    exp.GenerateReport(); 
}

On this button click must export data to excel but i gives such error on exp.dataToPrint = (ActionDatas)view.SourceCollection;:

Unable to cast object of type ‘System.Collections.ObjectModel.ObservableCollection`1[H_Pro.Logicstic+ActionData]’ to type ‘ActionDatas’.

Here is a some part of method which gets values

 public class ActionDatas : List<ActionData> { }

        #region toxls
         public class ExportExcel<T, U>
        where T : class
        where U : List<T>
    {
        public List<T> dataToPrint;

does anyone have an idea why im getting such error?

Answer 1

The data from ActionDatas might be implicitly being assigned to SourceCollection (possibly in XAML) which is an ObservableCollection<> (not the same thing as a List<>). It being an ObservableCollection is a good thing, since collection changes will automatically notify the listening WPF UI.

You should be able to simply assign an ActionDatas, and transfer the elements:

exp.dataToPrint = new ActionDatas();

foreach(ActionData data in view.SourceCollection) {
    exp.dataToPrint.Add(data);
}

Or something along those lines.

Update: If your datagrid ItemsSource is already an ActionDatas object, then you should assign it directly to the dataToPrint member, no need to put it in a view and then transfer back into a new collection.