asp.net - set text to textbox based on selected value from dropdownlist in gridview asp net -

i have 1 dropdown , 1 textbox in gridview. gridview contains subject name , in database there fees particular subject. want show fees textbox on every value selected dropdown.

i have done same functionality gives exact output want not after selection of subject, gives value on button click.

may have done wrong not found exact solution please help.

aspx code :

<asp:gridview id="gridview1" runat="server" showfooter="true" autogeneratecolumns="false" onrowdatabound="gridview1_rowdatabound" cssclass="eu_datatable">     <columns>         <asp:templatefield headertext="program name">             <itemtemplate>                 <asp:dropdownlist id="ddl_proglist" runat="server" appenddatabounditems="true" onselectedindexchanged="ddl_proglist_selectedindexchanged" controlstyle-width="160px">                     <asp:listitem value="-1">select</asp:listitem>                 </asp:dropdownlist>             </itemtemplate>         </asp:templatefield>         <asp:templatefield headertext="fees">             <itemtemplate>                 <asp:textbox id="txt_fees" runat="server" controlstyle-width="75px"></asp:textbox>             </itemtemplate>             <footerstyle horizontalalign="right" />             <footertemplate>                 <asp:button id="buttonadd" runat="server" text="add new row" onclick="buttonadd_click" />             </footertemplate>         </asp:templatefield>     </columns> </asp:gridview> 

code behind :

protected void gridview1_rowdatabound(object sender, gridviewroweventargs e) {     if (e.row.rowtype == datacontrolrowtype.datarow)     {         control ctrl = e.row.findcontrol("ddl_proglist");         if (ctrl != null)         {             dropdownlist dd = ctrl dropdownlist;              //sqlconnection conn = new sqlconnection(connstr);              clsprog_tb objprg = new clsprog_tb();             objprg.center_code = ddl_centercode.selecteditem.tostring();             dataset ds = clsuserlogiclayer.loadprograms(objprg);             dd.datatextfield = "prg_name";             dd.datavaluefield = "prg_name";             dd.datasource = ds.tables[0];             dd.databind();         }     } } protected void ddl_proglist_selectedindexchanged(object sender, eventargs e) {     dropdownlist ddl = sender dropdownlist;      foreach (gridviewrow row in gridview1.rows)     {          control ctrl = row.findcontrol("ddl_proglist") dropdownlist;         if (ctrl != null)         {             dropdownlist ddl1 = (dropdownlist)ctrl;              if (ddl.clientid == ddl1.clientid)             {                 textbox txt2 = row.findcontrol("txt_fees") textbox;                 clsprog_tb objprg = new clsprog_tb();                 objprg.center_code = ddl_centercode.selecteditem.tostring();                 objprg.prg_name = ddl1.selecteditem.tostring();                 dataset ds = clsuserlogiclayer.getprogfees(objprg);                 if (ds.tables[0].rows.count != 0)                 {                     txt2.text = ds.tables[0].rows[0][0].tostring();                  }             }         }     } } 

you can try update row , bind gridview again. need set gridview.seteditrow() before starting editing. way update datatable , bind again.

   protected void ddl_proglist_selectedindexchanged(object sender, eventargs e) {     dropdownlist ddl = sender dropdownlist;      foreach (gridviewrow row in gridview1.rows)     { gridview.seteditrow(row.rowindex);            control ctrl = row.findcontrol("ddl_proglist") dropdownlist;         if (ctrl != null)         {             dropdownlist ddl1 = (dropdownlist)ctrl;              if (ddl.clientid == ddl1.clientid)             {                 textbox txt2 = row.findcontrol("txt_fees") textbox;                 clsprog_tb objprg = new clsprog_tb();                 objprg.center_code = ddl_centercode.selecteditem.tostring();                 objprg.prg_name = ddl1.selecteditem.tostring();                 dataset ds = clsuserlogiclayer.getprogfees(objprg);                 if (ds.tables[0].rows.count != 0)                 {                     txt2.text = ds.tables[0].rows[0][0].tostring();                  }             }         }          gridview1.updaterow(row.rowindex, false);     } gridview1.databind(); }