c# - Cast expression tree to void -


given expression tree inner, want wrap inside no-op expression of type void. expression inner should still evaluated, return type should thrown away. how do it?

if curious why want it, 1 possible application such casting expression.switch, requires expression.switchcase expressions return same type.

my current workaround cast type object wrapping inner this: expression.block(inner, expression.constant(null)). such solution seems weird, bulks code, , possibly complicates generated msil code too.

one option use the overload of expression.switch() lets specify return type. if specify void, expressions of type accepted cases. in overload, need specify defaultbody , comparison parameters, can make them null.

another option indeed use expression.block(), again the overload lets specify type. in case, like:

expression.block(typeof(void), inner)

i don't expect have significant effect on generated il.


Comments

Post a Comment

Popular posts from this blog

get url and add instance to a model with prefilled foreign key :django admin -

Image
i have page in each contest shown in row. each row contains contest id , link other model names have foreign key contest. news model: class news(models.model): title = models.charfield(max_length=50, null=true) description = models.textfield() time = models.timefield( default= datetime.datetime.now().time()) contest = models.foreignkey(contest) i want use admin adding , changing these models. want when user clicks on 'news' has foreign key contest id=1, shows list of news value foreign key. use {% instance in instances %} <tr class="{% cycle 'row1' 'row2' %}"> <td>{{ instance.title }}</td> <td>{{ instance.starttime }}</td> <td>{{ instance.timespan }}</td> <td>{{ instance.date }}</td> <td><a href="/adm...
Read more

android - Keyboard hides my half of edit-text and button below it even in scroll view -

i having trouble keyboard covers edit-text , half of button in scroll view. here's layout , please tell me how should resolve problem. many questions on topic none of them s working me. <?xml version="1.0" encoding="utf-8"?> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:background="@drawable/bg" android:layout_height="match_parent"> <scrollview android:layout_width="match_parent" android:fillviewport="true" android:layout_height="match_parent"> <relativelayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <linearlayout android:layout_width="match_parent" android:layout_height="w...
Read more

css - Make div keyboard-scrollable in jQuery Mobile? -

from can tell, although jquery-mobile-powered pages can contain divs overflow set scroll or auto, , these divs can scrolled one-screen bar or mouse wheel, cannot scrolled using arrow keys, page-up/page-down, or home/end. instead, official "page" div (with data-role="page") absorbs input. perhaps other divs can't acquire focus, i'm not sure. is there way around this? edit: jsfiddle of simple example: https://jsfiddle.net/qogz0shx/ <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script> <script src="https://ajax.googleapis.com/ajax/libs/jquerymobile/1.4.5/jquery.mobile.min.js"> </script> <link rel="stylesheet" href="https://code.jquery.com/mobile/1.4.5/jquery.mobile-1.4.5.css"/> <style> #outer { overflow:scroll; height: 50vh; width: 50vw; } #inner { height: 500vh; width: 500vw; } ...
Read more