如何使用Xamarin（iOS）打开特定的PDF页面？

Question

我使用以下代码打开PDF文档。我想知道如何在特定页面上打开PDF，因为每次我运行代码时，文档都会从头开始打开。

<?php
// if session has not started:
session_start();

// load some basic configuration, including relative paths
// and variables needed ...
include_once( "../includes/configuration.php" );

// data connection
include_once( $Roster_RootPath . "includes/connect.php");

// values from Ajax code:
$region       = $_POST["region"];
$local_branch = $_POST["local_branch"];

// open the roster_branches table and get list
if( $region > 0 ) // check only needed for find_by_branch.php
{
   $branch_statement = "select * from roster_branches where region=" .  $region . " order by local";
}
else
{
   $branch_statement = "select * from roster_branches order by local";
}

// first, get the data from the table:
$branch_result = mysqli_query( $connect, $branch_statement );
if( !$branch_result )
{
   $out = "";
   $out .= "<div class='alert alert-danger'>";
   $out .= "<p><b>Error in SQL statement ...</b><br />";
   $errornum = mysqli_errno( $connect );
   $out .= "MySQL Error Number: " . $errornum . "<br />";
   $out .= "MySQL Error: " . mysqli_error( $connect ) . "<br />";
   $out .= "SQL Statement: " . $branch_statement . "</p>";
   $out .= "</div>";
   echo $out;
   die;   
}
else
{
   $out = "";
   // create select:
   $out = "<select class='form-control' id='local_branch' name='local_branch'>\n";

   // need the blank option:
   $out .= "   <option value=0 selected></option>\n";

   while( $branch_row = mysqli_fetch_array( $branch_result ) )
   {
      $id = $branch_row["rb_id"];
      $local = $branch_row["local"];
      $selected = "";
      if( $local_branch == $id )
      {
         $selected = " selected";
      }
      $out .= "<option value=" . $id . $selected . ">" . $local . "</option> \n";
   }

   $out .= "</select>\n";
   echo $out;      
} // we have something

?>