How can I set custom validation using controller in system config file in Magento 2?

Question

I want to set custom validation on system config file that "accept character do not allow any script tag" only accept like that

ex. config/group/field, config/group/field

Here is my system.xml file

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <tab id="ccc" translate="label" sortOrder="10">
            <label>Ccc</label>
        </tab>
        <section id="secureconfig" translate="label" sortOrder="130" showInDefault="1" showInWebsite="1" showInStore="1">
            <class>separator-top</class>
            <label>SecureConfig</label>
            <tab>ccc</tab>
            <resource>Ccc_SecureConfig::secure_config</resource>
            <group id="general" translate="label" type="text" sortOrder="10" showInDefault="1" showInWebsite="0" showInStore="0">
                <label>General Configuration</label>
                <field id="enable" translate="label" type="select" sortOrder="1" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Module Enable</label>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                </field>
                <field id="config_path" translate="label" type="textarea" sortOrder="1" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Config Path </label>
                    <comment>Add Config Path with , seprator Like (config/group/field, config/group/field)</comment>
                    <validate>required-entry validate-data</validate>
                </field>
            </group>
        </section>
    </system>
</config>

Answer 1

try below code

<field id="config_path" translate="label" type="textarea" sortOrder="1" showInDefault="1" showInWebsite="0" showInStore="0">
    <label>Config Path </label>
    <comment>Add Config Path with , seprator Like (config/group/field, config/group/field)</comment>
    <frontend_class>validate-alpha</frontend_class>
</field>

for validation, you need to add like this

<frontend_class>validate-alpha</frontend_class>

validate-alpha -- > Character only

validate-number -- > Number Only

required-entry --> required field