c# - Save data records and use it again without querying again into database -

i have 2 control, search button , export button. user 'search' data , data inserted datatable , bound gridview or repeater, , when user click export, datatable passed class generate excel file using data inside datatable.

in current code, search button , export button both query fetch data database. need search button query, , store data datatable or something, , when export button clicked use earlier data generate excel file.

here current code: report.aspx

    <asp:gridview id="gridview1" runat="server">         <columns>         </columns>     </asp:gridview> </body> 

report.aspx.cs

protected void page_load(object sender, eventargs e)         {             /* page load */         }  protected void btn_search_click(object sender, eventargs e)         {             datatable dt = getdata();             gridview1.datasource = dt;             gridview1.databind();         }  protected datatable getdata()     {         datatable datatable = new datatable();         /* query operation */             adapter.fill(datatable);         return datatable;     }  protected void btn_export_click(object sender, eventargs e)     {         var excelclass = new excelclass();         excelclass.exceldata = getdata();     } 

i attempt create datatable property in 'report.aspx.cs' , fill data when search clicked. when export , datatable empty again.

datatable datatable = new datatable(); protected void page_load(object sender, eventargs e)         {             /* page load */         }  protected void btn_search_click(object sender, eventargs e)         {             getdata();             gridview1.datasource = datatable ;             gridview1.databind();         }  protected void getdata()     {         /* query operation */             adapter.fill(datatable);     }  protected void btn_export_click(object sender, eventargs e)     {         var excelclass = new excelclass();         excelclass.exceldata = datatable;     } 

but, need fetch data once, when search clicked, , use data again when export it, wont query database twice.

there 3 ways can achieve mentioned below.

1. using session

you can use session affect performance of application/page if, example, datatable contains 10,000 records.

add datatable session:

datatable datatable= new datatable();  datatable= getdata();  session.add("datatable", datatable); 

retrive datatable session:

datatable datatable = session["datatable"] datatable 

or

datatable datatable= (datatable)session["datatable"]; 

2. export gridview1.datasource datatable

datatable datatable= gridview1.datasource datatable; 

3. iterate each row gridview datatable

//create new datatable. datatable datatable = new datatable();  //add columns datatable. foreach (tablecell cell in gridview1.headerrow.cells) {     datatable.columns.add(cell.text); }  //loop through gridview , copy rows. foreach (gridviewrow row in gridview1.rows) {     datatable.rows.add();     (int = 0; < row.cells.count; i++)     {         datatable.rows[row.rowindex][i] = row.cells[i].text;     } }