vb.net - Reusable function to adjust the width of combobox items to longest item in the list -

my intent able use function adjust width of drop down items included in drop down shown (length wise). i'm trying create function i'll able use multiple comboboxes. being called load cbo function, after data has been loaded not adjusting .dropdownwidth.

private sub adjustcombobox(byval comboboxname combobox)     dim maxwidth = 0     dim temp = 0      each item object in comboboxname.items         temp = textrenderer.measuretext(item.tostring(), comboboxname.font).width         if temp > maxwidth             maxwidth = temp         end if     next      comboboxname.dropdownwidth = maxwidth end sub 

edit:

comboboxload function

        dim da new sqldataadapter(sql, objconnection)         dim ds new dataset          da.fill(ds, "prov")          if ds.tables("prov").rows.count > 0             c                 .datasource = ds.tables("prov")                 .valuemember = "no"                 .displaymember = "name"                 .selectedindex = -1             end         end if 

first, use actual datasource, not items. allows short solution:

private function getmaxdatasize(dt datatable, mem string) int32      dim longestitem = dt.asenumerable.select(function(q) q.field(of string)(mem)).                 orderby(function(z) z.length).                 last()      ' assumes cbo's use same font     dim longestsize = textrenderer.measuretext(longestitem, cboe.font)     return longestsize.width +                 systeminformation.verticalscrollbarwidth + 5  end function 

note method accounts verticalscrollbarwidth , slight fudge factor account internal gutters, padding, margins etc. if different combos use different fonts, pass each method well. usage:

' "text" displaymember name / column name cboe.dropdownwidth = getmaxdatasize(dtlorem, "text") 

using "lorem ipsum dolor" fragments, 1 long one, result: