Impossibile eseguire il cast di oggetti di tipo 'Telerik.Web.UI.RadListViewDataItem' sul tipo 'Telerik.Web.UI.RadListViewEditableItem'.

[clo]

Hi,
pleas I need your help...
This is the error


...and this is all the code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.Adapters;
using Oracle.DataAccess.Client;
using Telerik.OpenAccess.Config.Sql;
using System.Data;
using Telerik.Web.UI;
using System.Configuration;
using System.IO;
using System.Collections;

namespace WebApplication1
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        private OracleConnection conn = new OracleConnection();
        string ConnString= "data source=OG_DB2;password=ghid101;user id=OG_GHIDONI";
        string sql = " select tasso_iva, data_inizio, data_fine from tassi_iva group by tasso_iva, data_inizio, data_fine";

        protected void Page_Load(object sender, EventArgs e)
        {
            string ConnString = "data source=OG_DB2;password=ghid101;user id=OG_GHIDONI";

            conn.ConnectionString = ConnString; //ccc associo la connection string con un connection object

            try
            {
                conn.Open();    //ccc apro la connessione

            }

            catch (Exception ex) // ccc catches any error
            {
                MessageBox.Show(ex.Message.ToString());
            }


        }

        protected void Page_Init(object sender, EventArgs e)
        {
            RadListView1.NeedDataSource += (s, args) =>
            {
                RadListView1.DataSource = GetDataSet(sql);
                // ccc il max per selezionare prima quello con la data d'inizio maggiore non gli piace! Trovare altra sol!!
            };

        }


        protected void RadListView1_ItemUpdating(object sender, RadListViewCommandEventArgs e)
        {
            RadListViewEditableItem editedItem = (RadListViewEditableItem)e.ListViewItem;
            Hashtable newValues = new Hashtable();
            editedItem.ExtractValues(newValues);

            DataTable IvaTable = RadListViewSource;

            //Locate the changed row in the DataSource
            DataRow[] changedRows = IvaTable.Select("tasso_iva = " + editedItem.GetDataKeyValue("tasso_iva"));

            if (changedRows.Length != 1)
            {
                e.Canceled = true;
                return;
            }

            //Update new values
            changedRows[0].BeginEdit();
            try
            {
                foreach (DictionaryEntry entry in newValues)
                {
                    changedRows[0][(string)entry.Key] = entry.Value;
                }
                changedRows[0].EndEdit();
                this.ViewState["lvds"] = IvaTable;
            }

            catch (Exception ex)
            {
                changedRows[0].CancelEdit();
                //output a warning message as necessary
                e.Canceled = true;
                 MessageBox.Show(ex.Message.ToString());
            }
            
        }

        protected void RadListView1_ItemInserting(object sender, RadListViewCommandEventArgs e)
        {
            RadListViewEditableItem insertedItem = (RadListViewEditableItem)e.ListViewItem;
            Hashtable newValues = new Hashtable();
            insertedItem.ExtractValues(newValues);
            DataTable IvaTable = RadListViewSource;

            DataRow newRow = IvaTable.NewRow();

            try
            {
                newRow["tasso_iva"] = IvaTable.Rows.Count + 1;
                foreach (DictionaryEntry entry in newValues)
                {
                    newRow[(string)entry.Key] = entry.Value;
                }
                IvaTable.Rows.Add(newRow);
                this.ViewState["lvds"] = IvaTable;
            }
            catch (Exception ex)
            {
                //output a warning message as necessary
                MessageBox.Show(ex.Message.ToString());
                e.Canceled = true;
            }
        }

        protected void RadListView1_ItemDeleting(object sender, RadListViewCommandEventArgs e)
        {
            try
            {
                DataTable IvaTable = this.RadListViewSource;

                DataColumn pk = IvaTable.Columns["tasso_iva"];
                DataColumn[] pkeys = new DataColumn[1];
                pkeys[0] = pk;
                IvaTable.PrimaryKey = pkeys;

                int id = int.Parse(e.CommandArgument.ToString());

                IvaTable.Rows.Find(id).Delete();
                IvaTable.AcceptChanges();
                this.ViewState["lvds"] = IvaTable;
            }
            catch (Exception ex)
            {
                //output a warning message as necessary
                MessageBox.Show(ex.Message.ToString());
                e.Canceled = true;
            }
        }

        private DataTable RadListViewSource
        {
            get
            {
                Object obj = ViewState["lvds"];
                if (obj != null)
                {
                    return (DataTable)obj;
                }
                else
                {
                    DataTable listViewDataSource;

                    listViewDataSource = new DataTable();

                    OracleDataAdapter adapter = new OracleDataAdapter(sql, ConnString);
                    adapter.Fill(listViewDataSource);

                    ViewState["lvds"] = listViewDataSource;
                    return listViewDataSource;
                }
            }
        }




        protected void RadListView1_NeedDataSource(object source, Telerik.Web.UI.RadListViewNeedDataSourceEventArgs e)
        {
            RadListView1.DataSource = GetDataSet(" select tasso_iva, max(data_inizio), data_fine from tassi_iva group by tasso_iva, data_inizio, data_fine");
            //+ "where data_inizio = to_date('01.01.01', 'DD.MM.YY')";
        }

        public DataSet GetDataSet(string query)
        {
            string ConnString = "data source=OG_DB2;password=ghid101;user id=OG_GHIDONI";
            //string qry = " select tasso_iva, max(data_inizio), data_fine from tassi_iva group by tasso_iva, data_inizio, data_fine";

            OracleDataAdapter adapter = new OracleDataAdapter(query, ConnString);

            DataSet ds = new DataSet();


            try
            {
                adapter.Fill(ds, "tassi_iva");
            }
            finally
            {
                conn.Close();
            }
            return ds;
        }

    }
}

Somebody can help me?
Thanks a lot

[clo]

I solved but now I have another one: (...