在我的管理仪表板中，我创建了一个自定义模块，用于使用自定义查询进行报告筛选。我需要添加另一个功能，将这些结果导出到CSV。我尝试创建一个非常简单的csv导出示例。

ob_end_clean();
$output .= \'column 1\'. \',\';
$output .= \'column 2\'. \',\';

$output .="\\n";
$output .=\'"data 1",\';
$output .=\'"data 2",\';
$output .="\\n";

$file = "custom_table";
$filename = $file."_".date("Y-m-d_H-i",time());

header("Content-type: application/vnd.ms-excel");
header("Content-disposition: csv" . date("Y-m-d") . ".csv");
header( "Content-disposition: filename=".$filename.".csv");

echo $output;

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Warning: Cannot modify header information - headers already sent by (output started at C:\\xampp\\htdocs\\rtlcbsasia\\wp-admin\\includes\\template.php:1947) in C:\\xampp\\htdocs\\rtlcbsasia\\wp-content\\plugins\\wpdm-reports\\wpdm-reports.php on line 39

Warning: Cannot modify header information - headers already sent by (output started at C:\\xampp\\htdocs\\rtlcbsasia\\wp-admin\\includes\\template.php:1947) in C:\\xampp\\htdocs\\rtlcbsasia\\wp-content\\plugins\\wpdm-reports\\wpdm-reports.php on line 40
column 1,column 2, "data 1","data 2",