c# - How Do I Sum Items in the List box? -

i have 2 listboxes, source , destination. destination listbox has items selected user.

how sum items in destination listbox?

the destination listbox has 2 data types string (description) , decimal (cost). want sum cost. here xaml code

<listbox height="237" horizontalalignment="left" margin="44,191,0,0" name="lstdestination" verticalalignment="top" width="264" grid.columnspan="2" itemssource="{binding source={staticresource myitemlist}}">     <listbox.itemtemplate>         <datatemplate>             <stackpanel orientation="vertical">                 <dockpanel >                    <textblock fontweight="bold" text="item:"  dockpanel.dock="left" margin="5,0,10,0"/>                    <textblock text="{binding path=resource}" foreground="green" fontweight="bold" />                    <textblock fontweight="bold" text="cost:"  dockpanel.dock="left" margin="5,0,10,0"/>                   <textblock text="{binding path=cost}" fontweight="bold" />                 </dockpanel>             </stackpanel>         </datatemplate>     </listbox.itemtemplate> </listbox> 

this code tried sum cost:

private decimal sumdlstbox() {     decimal totalcost;     foreach (var in lstdestination.selecteditems)     {         totalcost+=i.cost; //error thrown here                  }     return totalcost; } //data source list box source  var items = r in dc.iresources select r;         lstsource.itemssource = items; 

the user them selects items s/he needs, challenge total of selected items(which have been moved listbox destination)

to operate on bound data, should cast list of datatype you're working with. eg.

private decimal sumdlstbox() {     return lstdestination.selecteditems.cast<foo>().sum(f => f.cost); } 

where foo datatype of list bound control.