How to get data from a gridview at runtime on web form asp.net

Question

I have a gridview on an aspx page.

the gridview already has a datasource and is populated.

i am trying to get the data out of it like this when the user clicks a button:

DataTable dt = (DataTable)grdList.DataSource;

however it is showing this result as null!

i understand this to be an issue with postback/viewstate.

can someone please recommend to me a solution by which i can get data out of the gridview?>

Is the user clicking a button in the grid or on a form that the grid is part of? — gsirianni, Dec 08 '11 at 18:51
@gsirianni user is clicking on a button that is on the form, not the grid — Alex Gordon, Dec 08 '11 at 18:54
Is it a sqlDataSource or objectDataSource that binds to the data grid? If the table is quite large I may rerun the query through an object data source. If not, then saving the data table to the view state will suffice. — gsirianni, Dec 08 '11 at 19:00
This can be asked before. http://stackoverflow.com/questions/785799/how-can-i-export-a-gridview-datasource-to-a-datatable-or-dataset — Hanlet Escaño, Dec 08 '11 at 19:04

score 4 · Accepted Answer · answered Dec 08 '11 at 18:51

4

No you cannot get the data from asp.net gridview. Instead use this code.

Datatable dt = SomeMethodReturningDataTable();

Viewstate["Table"] = dt;

GridView.DataSource = ViewState["Table"];
Gridview.DataBind();

If you want to make chnages, pull out the table from viewstate and make changes and then push it again and bind it to grid.

answered Dec 08 '11 at 18:51

Why negative ? Any specific reason. – Dec 08 '11 at 18:53
when i try to do this:Viewstate["Table"] = (DataTable)grdList.DataSource; i am getting 'viewstate' does not exist in current context – Alex Gordon Dec 08 '11 at 18:53
This would work but page size will grow depending on table size. I wouldnt go with this approach unless sure there are always only few records returned. – Davide Piras Dec 08 '11 at 18:55
1

You never get Datatable from the datasource. As the asp.net datasource is volatile in nature. See my suggestion.... in my answer. – Dec 08 '11 at 18:56
@DavidePiras : You can have alternatives, 1. Sql Paging or 2.Compress the viewstate – Dec 08 '11 at 18:57
@See-Sharp how do you compress viewstate? – Alex Gordon Dec 08 '11 at 19:24

1 Answers1