c# - TextBox with an Error bob -

i want have textbox displays error bob next it. wrote below code:

<textbox text="my textbox" horizontalalignment="center" verticalalignment="center" height="75" width="75">     <textbox.template>         <controltemplate>             <dockpanel>                 <image..."error bob image added here"/>                 <border borderbrush="red" borderthickness="1.2"/>             </dockpanel>         </controltemplate>     </textbox.template> </textbox> 

i able see same in designer. when run solution, see textbox red border. image (i.e., error bob) not visible. can suggest why happens?

try set property lastchildfill="true" of dockpanel:

<textbox text="my textbox" horizontalalignment="center" verticalalignment="center" height="75" width="75">     <textbox.template>        <controltemplate>           <dockpanel lastchildfill="true">                     <textbox borderthickness="0"/>                     <textblock text="error bob image added here" width="100"/>                     <!--<image..."error bob image added here"/>-->                    <border borderbrush="red" borderthickness="1.2"/>                 </dockpanel>        </controltemplate>    </textbox.template> </textbox> 

you can use textblock width instead of image show text "error bob".

update: double checked , works. please, see following image:

in addition, can use stackpanel, if okay:

<textbox text="my textbox" horizontalalignment="center" verticalalignment="center" height="75" width="275">   <textbox.template>      <controltemplate>        <stackpanel orientation="horizontal">           <textbox borderthickness="0"/>           <textblock text="error bob image added here" width="100"/>                                   <border borderbrush="red" borderthickness="1.2"/>        </stackpanel>      </controltemplate>   </textbox.template> </textbox>