asp.net - How to resolve the error "String was not recognized as a valid Date Time in Vb.net " -

my code behind follows want enter date per displayed on textbox4 front end

 protected sub btnsave_click1(byval sender object, byval e eventargs) handles button2.click      dim dt2 oledbparameter     dt2 = cmd.createparameter     dt2.oledbtype = oledbtype.date     dim dt string = textbox4.innertext     dt2.value = datetime.parseexact(dt,"m/dd/yyyy", nothing)     dt2.parametername = "@startdate"     cmd.parameters.add(dt2)  end sub 

my front end code in aspx follows

 <div class="container" id="textbox4" runat="server" width="181px"  bordercolor="black" borderstyle="solid">         <div class="row">           <div class='col-sm-6'>             <div class="form-group">               <div class='input-group date' id='datetimepicker1'>                 <input type='text' class="form-control" />                 <span class="input-group-addon">                             <span class="glyphicon glyphicon-calendar"></span>                 </span>               </div>             </div>           </div>           <script type="text/javascript">               $(function () {                   $('#datetimepicker1').datetimepicker();               });           </script>         </div>       </div> 

protected sub btnsave_click1(byval sender object, byval e eventargs) handles button2.click  dim dt2 oledbparameter dt2 = cmd.createparameter dt2.oledbtype = oledbtype.date dt2.value = = textbox4.text dt2.parametername = "@startdate" cmd.parameters.add(dt2) 

end sub

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edited , works feedback , help.