将ASP.NET listview绑定到DataTable变量

Question

我将listview绑定到datatable变量。我的想法是在从ListView删除，插入，更新请求时修改DataTable，并仅在用户需要时将其保存到数据库。但是，在回发后，我的DataTable变为null。有什么办法可以解决吗？这是在没有连接数据库的情况下绑定ListView的正确方法吗？

    protected void Page_Load(object sender, EventArgs e)
    {
       if(!Page.IsPostBack){
          DataTable DTReceipts = new DataTable("DTReceipts"); 
          DTReceipts.Columns.AddRange(new DataColumn[] { 
          new DataColumn("ExpenseReceiptID", Type.GetType("System.Int32")),
          new DataColumn("TransactionSeqNumber", Type.GetType("System.Int32")),
          new DataColumn("TransactionSeqSub", Type.GetType("System.String")),
          new DataColumn("TransactionDate", Type.GetType("System.DateTime")),
          new DataColumn("ReceiptNumber", Type.GetType("System.String")),
          new DataColumn("Vendor_EntityID", Type.GetType("System.Int32")),
          new DataColumn("Description", Type.GetType("System.String")),
          new DataColumn("SubProjectID", Type.GetType("System.Int32")),
          new DataColumn("AllocationID", Type.GetType("System.Int32")),
          new DataColumn("AllocationScope", Type.GetType("System.String")),
          new DataColumn("DeductFromVendor_EntityID", Type.GetType("System.Int32")),
          new DataColumn("DeductionAmount", Type.GetType("System.Double")),
          new DataColumn("EmployeeID", Type.GetType("System.Int32"))
         });
         for (int i = 1; i <= 20; i++)
         {
          DataRow drr = DTReceipts.NewRow();
          drr["ExpenseReceiptID"] = DBNull.Value;
          drr["TransactionSeqNumber"] = i.ToString();
          drr["TransactionSeqSub"] = "";
          drr["TransactionDate"] = DBNull.Value;
          drr["ReceiptNumber"] = DBNull.Value;
          drr["Vendor_EntityID"] = DBNull.Value;
          drr["Description"] = DBNull.Value;
          drr["SubProjectID"] = DBNull.Value;
          drr["AllocationID"] = DBNull.Value;
          drr["AllocationScope"] = DBNull.Value;
          drr["DeductFromVendor_EntityID"] = DBNull.Value;
          drr["DeductionAmount"] = DBNull.Value;
          drr["EmployeeID"] = DBNull.Value;
          DTReceipts.Rows.Add(drr);
         }
         ExpenseReceiptsList.DataSource = DTReceipts;
         ExpenseReceiptsList.DataBind(); 
     }
   }