I was trying to use a generic select * from table statment and have the results returned in an array. I finally came up with this solution, others have similar solutions, but they where not working for me. 
<?php
    //Snip use normal methods to get to this point
    $stmt->execute();
    $metaResults = $stmt->result_metadata();
    $fields = $metaResults->fetch_fields();
    $statementParams='';
     //build the bind_results statement dynamically so I can get the results in an array
     foreach($fields as $field){
         if(empty($statementParams)){
             $statementParams.="\$column['".$field->name."']";
         }else{
             $statementParams.=", \$column['".$field->name."']";
         }
    }
    $statment="\$stmt->bind_result($statementParams);";
    eval($statment);
    while($stmt->fetch()){
        //Now the data is contained in the assoc array $column. Useful if you need to do a foreach, or 
        //if your lazy and didn't want to write out each param to bind.
    }
    // Continue on as usual.
?>

The following function taken from PHP Cookbook 2, returns an associative array of a row in the resultset, place in while loop to iterate through whole result set.

<?php
public function fetchArray () {
   $data = mysqli_stmt_result_metadata($this->stmt);
        $fields = array();
        $out = array();

        $fields[0] = &$this->stmt;
        $count = 1;

        while($field = mysqli_fetch_field($data)) {
            $fields[$count] = &$out[$field->name];
            $count++;
        }
        
        call_user_func_array(mysqli_stmt_bind_result, $fields);
        mysqli_stmt_fetch($this->stmt);
        return (count($out) == 0) ? false : $out;

    }
?>

I tried the mentioned stmt_bind_assoc() function, but somehow, very strangely it doesn't allow the values to be written in an array! In the while loop, the row is fetched correctly, but if I write $array[] = $row;, the array will be filled up with the last element of the dataset... Unfortunately I couldn't find a solution.

This function uses the same idea as the last, but instead binds the fields to a given array. 
<?php
function stmt_bind_assoc (&$stmt, &$out) {
    $data = mysqli_stmt_result_metadata($stmt);
    $fields = array();
    $out = array();

    $fields[0] = $stmt;
    $count = 1;

    while($field = mysqli_fetch_field($data)) {
        $fields[$count] = &$out[$field->name];
        $count++;
    }    
    call_user_func_array(mysqli_stmt_bind_result, $fields);
}

// example

$stmt = $mysqli->prepare("SELECT name, userid FROM somewhere");
$stmt->execute();

$row = array();
stmt_bind_assoc($stmt, $row);

// loop through all result rows
while ($stmt->fetch()) {
    print_r($row);
}
?>

IMPORTANT note: Be careful when you use this function with big result sets or with BLOB/TEXT columns. When one or more columns are of type (MEDIUM|LONG)(BLOB|TEXT) and ::store_result() was not called mysqli_stmt_fetch() will try to allocate at least 16MB for every such column. It _doesn't_ matter that the longest value in the result set is for example 30 bytes, 16MB will be allocated. Therefore it is not the best idea ot use binding of parameters whenever fetching big data. Why? Because once the data is in the mysql result set stored in memory and then second time in the PHP variable.