c# - How to Bind a nullable bool in VM to RadRadioButton -

i struggling how go this? in vm have nullable bool property want bind yes/no(true/false) radradiobutton. can point me in right direction?

vm

public bool? issds { get; set; } 

view

<telerik:label content="self directed support" /> <stackpanel orientation="horizontal">      <telerik:radradiobutton x:name="selfdirectedsupportyes" content="yes" />      <telerik:radradiobutton x:name="selfdirectedsupportno" content="no" /> </stackpanel> 

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edit

i thought working mistaken. yes binding. below what's on view, createauthview:

<stackpanel orientation="horizontal" margin="3" grid.column="1" grid.row="2">    <telerik:radradiobutton x:name="authorization_selfdirectedsupportyes" groupname="sds" content="yes" />     <telerik:radradiobutton x:name="authorization_selfdirectedsupportno" groupname="sds" content="no" /> </stackpanel> 

and here corresponding portion on viewmodel, createauthviewmodel:

public authorization authorization {         {        return this.authorization;     }     set     {        if (authorization != value)        {           this.authorization = value;           notifyofpropertychange(() => authorization);                            }     } } 

and property on model, authorization:

public bool? selfdirectedsupportyes {       {       return this.selfdirectedindicator;    }    set    {       this.selfdirectedindicator = value;       this.onpropertychanged();    } } 

ischecked of type nullable<bool>, can bind directly "yes" radio button. , if set same groupname both radio buttons, don't need bind "no" radio button @ (since checking "no" uncheck "yes")

<telerik:label content="self directed support" /> <stackpanel orientation="horizontal">      <telerik:radradiobutton x:name="selfdirectedsupportyes" groupname="selfdirectedsupportoption" content="yes" ischecked="{binding issds}" />      <telerik:radradiobutton x:name="selfdirectedsupportno" groupname="selfdirectedsupportoption" content="no" /> </stackpanel>