Php 警告：substr\u count（）：中的子字符串为空

我有个问题想不出来

如果一个WP页面/帖子模板上有两个重力表单，则会显示错误

警告：substr_count（）：第176行/home/joenygren/public_html/wp content/plugins/commission-rates-calculator 0423/commission_rates_calculator.php中的空子字符串

有什么想法吗

    <?php
    /**
    * Plugin Name: Commission Rates Calculator
    * Plugin URI: http://ellaking.net
    * Description: Commission Rates Calculator
    * Version: 1.0.1
    * Author: ellaking
    * Author URI: http://ellaking.net
    **/

class Commission_Rates_Calculator{

    private $fdate;

    function commission_rates_calculator(){
        add_action( 'crc_init', array( &$this, 'crc_enqueue_scripts') );
        add_filter('widget_text', 'do_shortcode');

        //add_filter('gform_field_value_fdate', array( &$this, 'populate_fdate') );
        //add_filter('gform_pre_submission', array( &$this, 'add_fdate') );
        add_filter("gform_pre_render", array( &$this, "populate_dropdown"));

//Note: when changing drop down values, we also need to use the gform_admin_pre_render so that the right values are displayed when editing the entry.
//add_filter("gform_admin_pre_render", array( &$this, "populate_dropdown"));

//Note: this will allow for the labels to be used during the submission process in case values are enabled
add_filter('gform_pre_submission_filter', array( &$this, 'populate_dropdown'));



        if(is_admin()){
            add_action( 'admin_menu', array( &$this, 'crc_settings_page') );
        }

        add_shortcode('commission_rates_calculator', array( &$this, 'crc_show_calculator') );
    }

    function crc_settings_page() {
        add_options_page('Commission Rates Calculator', 'Commission Rates Calculator', 'manage_options', 'crc_settings', array( &$this, 'crc_settings'));
    }

    function crc_settings(){
        if ( isset( $_POST['save_crc'] ) ) { 
            $new_crc_rate = $old_crc_rate = get_option('crc_rate'); 
            $new_crc_rate = $_POST['crc_rate'];
            $new_crc_anticipated_time = $old_crc_anticipated_time = get_option('crc_anticipated_time'); 
            $new_crc_anticipated_time = $_POST['crc_anticipated_time'];


            if ( $old_crc_rate != $new_crc_rate ) {
                update_option( 'crc_rate', $new_crc_rate );
            }
            if ( $old_crc_anticipated_time != $new_crc_anticipated_time ) {
                update_option( 'crc_anticipated_time', $new_crc_anticipated_time );
            }  
        }

        $crc_rate = get_option('crc_rate');
        $crc_anticipated_time = get_option('crc_anticipated_time');
        if(empty($crc_rate)){
            $crc_rate = 0.00075;
        }
        if(empty($crc_anticipated_time)){
            $crc_anticipated_time = 10;
        }

        ?>

<script type="text/javascript">
jQuery(document).ready(function() {
    jQuery("#crc_form").submit(function(){
        var csc_rate = jQuery("#crc_rate_text").val();
        var crc_anticipated_time = jQuery("#crc_anticipated_time_text").val();
        if(isNaN(csc_rate)){ 
          alert("Please enter a decimal such as 0.00075");
          jQuery("#crc_rate_text").val('');
          jQuery("#crc_rate_text").focus();
          return false;
        }
        if(isNaN(crc_anticipated_time)){ 
          alert("Please enter a anticipated time such as 10");
          jQuery("#crc_anticipated_time_text").val('');
          jQuery("#crc_anticipated_time_text").focus();
          return false;
        }
    });
});

</script>
<div class="wrap">
    <h2>Commission Rates Calculator Settings</h2>
    <table class="form-table">
        <tbody>
            <form method="post" id="crc_form" >
                <tr valign="top">
                    <th scope="row">Commission Rate</th>
                    <td>
                        <label for="crc_rate">Please enter a decimal such as 0.00075:</label><br /><br />
                        <input type="text" name="crc_rate" id="crc_rate_text" value="<?php echo $crc_rate;?>" />
                    </td>
                </tr>
                <tr valign="top">
                    <th scope="row">Anticipated Time</th>
                    <td>
                        <p>
                            <label for="crc_anticipated_time">Please enter a anticipated time such as 10:</label><br /><br />
                            <input type="text" name="crc_anticipated_time" id="crc_anticipated_time_text" value="<?php echo $crc_anticipated_time;?>" />&nbsp;&nbsp;days
                        </p>                       
                    </td>
                </tr>
                <tr valign="top">
                    <td>
                        <p>
                            <input type="hidden" name="save_crc" value="1" />
                            <input type="submit" name="Submit" class="button-primary autowidth" value="Save" />
                        </p>                       
                    </td>
                </tr>

            </form>
        </tbody>
    </table>
</div>
        <?php

    }

    function crc_enqueue_scripts(){
        $crc_rate = get_option('crc_rate'); 
        $crc_anticipated_time = get_option('crc_anticipated_time');
        if(empty($crc_rate)){
            $crc_rate = 0.00075;
        }
        if(empty($crc_anticipated_time)){
            $crc_anticipated_time = 10;
        }
        wp_enqueue_style( 'crc-style', plugin_dir_url( __FILE__ ) . 'css/crc_style.css' );
        wp_enqueue_style( 'crc-jquery-ui-css', plugin_dir_url( __FILE__ ) . 'css/ui-lightness/jquery-ui-datepicker.css' );
        wp_enqueue_script( 'crc-jquery-ui', plugin_dir_url( __FILE__ ) . 'js/jquery-ui-datepicker.min.js', array( 'jquery' ) );
        wp_enqueue_script( 'crc-script', plugin_dir_url( __FILE__ ) . 'crc_script.js', array( 'jquery' ) );

        wp_localize_script('crc-script', 'crc_script_options', array('crc_rate' => $crc_rate, 'crc_anticipated_time' => $crc_anticipated_time));
    }

    function crc_show_calculator(){
        do_action( 'crc_init' );

        $mytime = time().rand();

        $script = '<script type="text/javascript">';
        $script .= file_get_contents(plugin_dir_path( __FILE__ ).'crc_script.js');
        $script .= '</script>';


        $html = file_get_contents(plugin_dir_path( __FILE__ ).'template.php');
        $html=str_replace('[plugin_dir_url]',plugin_dir_url( __FILE__ ),$html);

        $output = $script.$html;
        $output = str_replace('crc_advance_date','crc_advance_date_'.$mytime,$output);
        $output = str_replace('crc_closed_date','crc_closed_date_'.$mytime,$output);
        $output = str_replace('crc_amount','crc_amount_'.$mytime,$output);
        $output = str_replace('crc_pay','crc_pay_'.$mytime,$output);
        $output = str_replace('crc_get_pay','crc_get_pay_'.$mytime,$output);
        $output = str_replace('crc_datediff','crc_datediff_'.$mytime,$output);

        return $output;
    }

    function populate_dropdown($form){



        $have_crc = false;
        if($form['fields']){
            foreach($form['fields'] as $field){
                if(substr_count('[commission_rates_calculator]',$field['content']) > 0){
                    $have_crc = true;
                    break;
                }
            }
            if($have_crc){
                $output = '<script type="text/javascript">';
                foreach($form['fields'] as $field){
                    if($field['label'] == 'crc_advance_date'){
                        $output .= 'var crc__advance_date_gform_id = "input_'.$form['id'].'_'.$field['id'].'";'."\n";
                    }
                    if($field['label'] == 'crc_closed_date'){
                        $output .= 'var crc__closed_date_gform_id = "input_'.$form['id'].'_'.$field['id'].'";'."\n";
                    }
                    if($field['label'] == 'crc_amount'){
                        $output .= 'var crc__amount_gform_id = "input_'.$form['id'].'_'.$field['id'].'";'."\n";
                    }
                    if($field['label'] == 'crc_pay'){
                        $output .= 'var crc__pay_gform_id = "input_'.$form['id'].'_'.$field['id'].'";'."\n";
                    }
                }
                $output .= '</script>';
                echo $output;
            }
        }
        //print_r($form);

        return $form;
    }



}
$commission_rates_calculator = new Commission_Rates_Calculator();
?>

jQuery（文档）.ready（函数（）{
jQuery（“#crc_表单”）.submit（函数（）{
var csc_rate=jQuery（“#crc_rate_text”）.val（）；
var crc_expected_time=jQuery（“#crc_expected_time_text”）.val（）；
if（isNaN（csc_rate））{
警报（“请输入小数点，如0.00075”）；
jQuery（“#crc#U rate_text”）.val（“”）；
jQuery（“#crc#U rate_text”）.focus（）；
返回false；
}
if（isNaN（crc\u时间））{
警报（“请输入预期时间，如10”）；
jQuery（“#crc#u expected_time_text”）.val（“”）；
jQuery（“#crc#u expected_time_text”）.focus（）；
返回false；
}
});
});
佣金率计算器设置
佣金率
请输入小数点，如0.00075:


请向我们展示代码，而不仅仅是错误消息。您可能会看到类似于
substr\u count（$string，'）
的内容。“针”参数不能为空。但是，由于您没有显示实际的代码，我们无法帮助您。在这里出现过两次…对不起，这里的新手。我假设第176行是
if（substr\u count（“[commission\u rates\u calculator]”，$field['content']）>0{
。如何调用
populate\u dropdown（）
？