wpf - How to switch between 2 data sources for ListBox.ItemsSource -

-

what best/elegant way bind itemscontrol.itemssource 2 different sources best on given property?

the binding should done 1 of 2 collection, selection collection itemscontrol bound should based on property.

i have view bound viewmodel. collections want bind located in different hierarchy path under viewmodel.

i've solution based on multibinding think there should more elegant solution.

<collectionviewsource x:key="cvs">       <collectionviewsource.source  >           <multibinding converter="{staticresource mymultibindingconverter}">               <binding  path="xxxx.yyyy.observablecollection1"  />               <binding path="xxxx.observablecollection2" />                               </multibinding>       </collectionviewsource.source>                             </collectionviewsource>  <listbox  x:name="mylistbox"                                              itemssource="{binding source={staticresource cvs}}" />

the converter:

public class mymultibindingconverter : imultivalueconverter {     public object convert(object[] values, type targettype, object parameter,         system.globalization.cultureinfo culture)     {          foreach (var item in values)         {             if(mydependecyproperty == getfirstcollection)             {               //make sure item of first collection type based on item property               return item;              }             else             {               //make sure item of second collection type               return item;             }          }         return null;     }      public object[] convertback(object value, type[] targettypes, object parameter,         system.globalization.cultureinfo culture)     {         throw new notimplementedexception();     } }

a datatrigger more appropriate here since want change itemssource binding based on value

<style x:key="mylistboxstyle" targettype="listbox">     <setter property="itemssource" value="{binding xxx.observablecollection2}" />     <style.triggers>         <datatrigger binding="{binding somevalue}" value="secondcollection">             <setter property="itemssource" value="{binding xxx.yyy.observablecollection2}" />         </datatrigger>     </style.triggers> </style>

unlike converter, datatrigger correctly re-evaluated whenever triggered value changes


Comments

Post a Comment

Popular posts from this blog

java - Jmockit String final length method mocking Issue -

-
using jmockit 1.2 jar, trying mock string's length method getting unexpected invocation exception: failed: test java.lang.illegalstateexception: missing invocation mocked type @ point; please make sure such invocations appear after declaration of suitable mock field or parameter @ stringdemo.testa$1.<init>(testa.java:17) @ stringdemo.testa.test(testa.java:13) i using testng: @test public void test() throws exception { new expectations() { @mocked("length") string astring; { astring.length(); result = 2; } }; system.out.println(a.showa("test")); } } actual class a: public class { public static int showa(string str){ int a= str.length(); return a; } } this wrong way of recording expected results. shouldn't mock , record string's length() method, record showa() instead. here solution @suppresswarnings("unused...
Read more

What is the difference between data design and data model(ERD) -

-
i have google question , find answer in day. know, data design many many table have list column,and mark pk , fk. why er-diagram have find this? data design process of designing database. main output of data design detailed logical data model of database. some people data design includes of needed logical , physical design choices , physical storage parameters needed generate design in data definition language. technically, database analysis, database analysts (dbas) trained do. while person can both data design , database analysis, these 2 different tasks. data design models data. database analysis takes model , applies 1 or more database engines (relational, hierarchical, nosql). a logical data model 1 of main outputs of data design. data model represented entity relationship diagram, or er diagram.
Read more

ios - Can NSManagedObject conform to NSCoding -

-
i need transfer single object across device. right converting nsmanagedobject dictionary , archiving , sending nsdata. upon receiving unarchiving it. transfer nsmanagedobject archiving , unarchiving instead of creating intermediate data object. @interface test : nsmanagedobject<nscoding> @property (nonatomic, retain) nsstring * title; @end @implementation test @dynamic title; - (id)initwithcoder:(nscoder *)coder { self = [super init]; if (self) { self.title = [coder decodeobjectforkey:@"title"]; //<crash } return self; } - (void)encodewithcoder:(nscoder *)coder { [coder encodeobject:self.title forkey:@"title"]; } @end nsdata *archivedobjects = [nskeyedarchiver archiveddatawithrootobject:testobj]; nsdata *objectsdata = archivedobjects; if ([objectsdata length] > 0) { nsarray *objects = [nskeyedunarchiver unarchiveobjectwithdata:objectsdata]; } the problem above code is. crashes @ self.title in initwithcoder sa...
Read more