Storing and retrieving datatable from session
开发者_开发问答How to store a datatable in session and to retrieve the values from the session in c#.net?
Add a datatable into session:
DataTable Tissues = new DataTable();
Tissues = dal.returnTissues("TestID", "TestValue");// returnTissues("","") sample function for adding values
Session.Add("Tissues", Tissues);
Retrive that datatable from session:
DataTable Tissues = Session["Tissues"] as DataTable
or
DataTable Tissues = (DataTable)Session["Tissues"];
To store DataTable
in Session:
DataTable dtTest = new DataTable();
Session["dtTest"] = dtTest;
To retrieve DataTable
from Session:
DataTable dt = (DataTable) Session["dtTest"];
You can do it like that but storing a DataSet object in Session is not very efficient. If you have a web app with lots of users it will clog your server memory really fast.
If you really must do it like that I suggest removing it from the session as soon as you don't need the DataSet.
this is just as a side note, but generally what you want to do is keep size on the Session and ViewState small. I generally just store IDs and small amounts of packets in Session and ViewState.
for instance if you want to pass large chunks of data from one page to another, you can store an ID in the querystring and use that ID to either get data from a database or a file.
PS: but like I said, this might be totally unrelated to your query :)
A simple solution for a very common problem
// DECLARATION
HttpContext context = HttpContext.Current;
DataTable dt_ShoppingBasket = context.Session["Shopping_Basket"] as DataTable;
// TRY TO ADD rows with the info into the DataTable
try
{
// Add new Serial Code into DataTable dt_ShoppingBasket
dt_ShoppingBasket.Rows.Add(new_SerialCode.ToString());
// Assigns new DataTable to Session["Shopping_Basket"]
context.Session["Shopping_Basket"] = dt_ShoppingBasket;
}
catch (Exception)
{
// IF FAIL (EMPTY OR DOESN'T EXIST) -
// Create new Instance,
DataTable dt_ShoppingBasket= new DataTable();
// Add column and Row with the info
dt_ShoppingBasket.Columns.Add("Serial");
dt_ShoppingBasket.Rows.Add(new_SerialCode.ToString());
// Assigns new DataTable to Session["Shopping_Basket"]
context.Session["Shopping_Basket"] = dt_PanierCommande;
}
// PRINT TESTS
DataTable dt_To_Print = context.Session["Shopping_Basket"] as DataTable;
foreach (DataRow row in dt_To_Print.Rows)
{
foreach (var item in row.ItemArray)
{
Debug.WriteLine("DATATABLE IN SESSION: " + item);
}
}
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