asp.net - Why is the DataItem property null for this DataGridItem here? -

problem

i have buttoncolumn edit row defined this:

<asp:buttoncolumn datatextfield="job_code" buttontype="linkbutton" headertext="job code"     commandname="edit"></asp:buttoncolumn> 

and in onitemcommand handler datagrid have code:

if e.commandname = "edit"     dim o listdatamodel = ctype(e.item.dataitem, listdatamodel)     if o nothing         exit sub     end if      ... end if 

but e.item.dataitem null here.

i've looked through related questions , verified following:

1. the itemtype of e.item set listitemtype.item , therefore should allowed house dataitem. jives msdn documentation.
2. i leveraged data binding -see code section below.
3. i have set datakeyfield attribute on asp:datagrid this: datakeyfield="job_code".

data binding code (happens in search method)

using reader sqldatareader = cmd.executereader()     dim list list(of listdatamodel) = new list(of listdatamodel)      while reader.read()         list.add(new listdatamodel                  {                      ...                  })     end while      dgsearchresults.datasource = list     dgsearchresults.databind() end using 

now, search method onserverclick event handler input button. flow user search results , click on 1 of command button edit row, therefore search method not run when onitemcommand handler fired.

alright, resolution ended bit convoluted. first ended having store search result set in session, built dictionary that:

dim cache dictionary(of string, listdatamodel) = new dictionary(of string, listdatamodel) 

and added dictionary when building listdatamodel objects. then, in onitemcommand handler ended having use reflection this:

dim cache dictionary(of string, listdatamodel) = ctype(session("searchresults"), dictionary(of string, listdatamodel)) if cache nothing     exit sub end if  dim prop propertyinfo = e.commandsource.gettype().getproperty("text") if prop nothing     exit sub end if  dim o listdatamodel = cache(prop.getvalue(e.commandsource, nothing).tostring()) if o nothing     exit sub end if 

as can see first pulled "searchresults" out of session, tried @ text property of datagridlinkbutton. had use reflection because datagridlinkbutton class isn't visible. finally, if found property, pulled off value.

though works, , hope solution by-product of else weird in application i'm maintaining, it's not wanted in end. pretty poor interface datagrid -but asp.net 2.0 , it's old stuff!