wpf - How do I data bind to a union case value within XAML? -

how data bind union case value within xaml?

currently data-bound value pointing string20 object instead of actual string value union case (i.e. string20) wraps around.

example:

<listview itemssource="{binding modules}" displaymemberpath="author.first" /> 

author definition:

type name = {      first:string20     last:string20     suffix:string20 option  }  type module = {      author:name     duration:duration  } 

xaml:

<window x:class="client.mainwindow"         ...         xmlns:managemodules="clr-namespace:managemodules;assembly=managemodules">      <window.datacontext>         <managemodules:creationviewmodel />     </window.datacontext>      <grid>         <listview itemssource="{binding modules}" displaymemberpath="author.first"                    textelement.foreground="lightblue" background="black" />     </grid> </window> 

viewmodel:

namespace managemodules     ...     type creationviewmodel() =         inherit viewmodelbase()         let name =      { first=string20("scott"); last=string20("nimrod"); suffix=none }         let duration =  { hours=1; minutes=30; seconds=0 }         let moduleitem = { author=name; duration=duration }          let mutable (_modules:module observablecollection) = observablecollection()          _modules.add(moduleitem)          member this.modules             get()      = _modules             , set(value)  = _modules <- value          member this.add moduleitem =              _modules.add(moduleitem) 

business domain:

module managemodule.entities  type duration = {      hours:int     minutes:int     seconds:int  }  type string20 = string20 of string  type name = {      first:string20     last:string20     suffix:string20 option  }  type module = {      author:name     duration:duration  }  , section =      | introduction of module     | conclusion of module     | content of module list 

my recommendation modify string20 includes additional member plain string value - , can bind ordinary string member.

to add member type, can write:

type string20 =    | string20 of string   member this.value =      let (string20(str)) =     str 

then should able write:

<listview itemssource="{binding modules}" displaymemberpath="author.first.value" /> 

there more sophisticated ways solve - guess wpf has mechanism specifying transformations happen in bindings behind scenes - adding value member simple start.