c# - Changing FontSize dynamically in windows phone 8.1 application -

i need change application font size dynamically resource dictionary using slider control

for setting common font size created this

 <x:double x:key="versefontsize">30</x:double> 

and called style in textblock this

<style x:key="title_subtext" targettype="textblock">         <setter property="verticalalignment" value="center"/>         <setter property="horizontalalignment" value="center"/>         <setter property="foreground" value="{staticresource foregroundcolorbrush}"/>         <setter property="fontweight" value="normal"/>         <setter property="fontsize" value="{staticresource versefontsize}"/>         <setter property="margin" value="0,5"/>     </style> 

now want increase or decrease font size using slider control.

i spend whole day making 1 solution , tried many, nothing works

please me guys solve issue.

dynamicresource serves exact purpose in wpf. it's not available on windows phone.

a simple solution bind viewmodel in typical way. want viewmodel available across pages, suggest putting in application resources. sample class:

public class dynamicresources : viewmodelbase {     private double versefontsize;     public double versefontsize     {         { return versefontsize; }         set         {             versefontsize = value;             raisepropertychanged();         }     } } 

the example above uses mvvmlight's viewmodelbase. add main resourcedictionary in app.xaml:

<local:dynamicresources x:key="dynamic" versefontsize="30"/> 

bind in following way:

fontsize="{binding versefontsize, source={staticresource dynamic}}" 

the problem bindings in setters aren't available on windows phone well. can try 1 of workarounds described here: silverlight: how use binding in setter style (or equivalent work around)

and modify value codebehind this:

private void buttonbase_onclick(object sender, routedeventargs e) {     dynamicresources resources = (dynamicresources)app.current.resources["dynamic"];     resources.versefontsize = resources.versefontsize + 1; } 

as resource application-wide, pages updated.