How to add products to a custom product link type grid in Magento 2?

The dataprovider is set to $scope . '_product_listing' in vendor/magento/module-catalog/Ui/DataProvider/Product/Form/Modifier/Related.php – getGrid($scope) function, we need to create UI component like, so as per our example the custom link type code is ‘parts’ we need to create parts_product_listing.xml UI component.

File Path: app/code/Mage2/CustomProductLink/view/adminhtml/ui_component/parts_product_listing.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<listing xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Ui:etc/ui_configuration.xsd">
    <argument name="data" xsi:type="array">
        <item name="js_config" xsi:type="array">
            <item name="provider" xsi:type="string">parts_product_listing.parts_product_listing_data_source</item>
        </item>
    </argument>
    <settings>
        <spinner>product_columns</spinner>
        <deps>
            <dep>parts_product_listing.parts_product_listing_data_source</dep>
        </deps>
    </settings>
    <dataSource name="parts_product_listing_data_source" component="Magento_Ui/js/grid/provider">
        <settings>
            <storageConfig>
                <param name="cacheRequests" xsi:type="boolean">false</param>
            </storageConfig>
            <updateUrl path="mui/index/render"/>
        </settings>
        <aclResource>Magento_Catalog::products</aclResource>
        <dataProvider class="Magento\Catalog\Ui\DataProvider\Product\Related\RelatedDataProvider" name="parts_product_listing_data_source">
            <settings>
                <requestFieldName>id</requestFieldName>
                <primaryFieldName>entity_id</primaryFieldName>
            </settings>
        </dataProvider>
    </dataSource>
    <listingToolbar name="listing_top">
        <filters name="listing_filters">
            <argument name="data" xsi:type="array">
                <item name="config" xsi:type="array">
                    <item name="params" xsi:type="array">
                        <item name="filters_modifier" xsi:type="array"/>
                    </item>
                    <item name="observers" xsi:type="array">
                        <item name="filters" xsi:type="object">Magento\Catalog\Ui\Component\Listing\Filters</item>
                    </item>
                </item>
            </argument>
            <settings>
                <statefull>
                    <property name="applied" xsi:type="boolean">false</property>
                </statefull>
            </settings>
        </filters>
        <paging name="listing_paging"/>
    </listingToolbar>
    <columns name="product_columns" class="Magento\Catalog\Ui\Component\Listing\Columns">
        <settings>
            <childDefaults>
                <param name="fieldAction" xsi:type="array">
                    <item name="provider" xsi:type="string">partsProductGrid</item>
                    <item name="target" xsi:type="string">selectProduct</item>
                    <item name="params" xsi:type="array">
                        <item name="0" xsi:type="string">${ $.$data.rowIndex }</item>
                    </item>
                </param>
            </childDefaults>
        </settings>
        <selectionsColumn name="ids" sortOrder="0">
            <settings>
                <indexField>entity_id</indexField>
                <preserveSelectionsOnFilter>true</preserveSelectionsOnFilter>
            </settings>
        </selectionsColumn>
        <column name="entity_id" sortOrder="10">
            <settings>
                <filter>textRange</filter>
                <label translate="true">ID</label>
                <sorting>asc</sorting>
            </settings>
        </column>
        <column name="thumbnail" class="Magento\Catalog\Ui\Component\Listing\Columns\Thumbnail" component="Magento_Ui/js/grid/columns/thumbnail" sortOrder="20">
            <settings>
                <altField>name</altField>
                <hasPreview>1</hasPreview>
                <addField>true</addField>
                <label translate="true">Thumbnail</label>
                <sortable>false</sortable>
            </settings>
        </column>
        <column name="name" sortOrder="30">
            <settings>
                <addField>true</addField>
                <filter>text</filter>
                <label translate="true">Name</label>
            </settings>
        </column>
        <column name="attribute_set_id" component="Magento_Ui/js/grid/columns/select" sortOrder="40">
            <settings>
                <options class="Magento\Catalog\Model\Product\AttributeSet\Options"/>
                <filter>select</filter>
                <dataType>select</dataType>
                <label translate="true">Attribute Set</label>
            </settings>
        </column>
        <column name="attribute_set_text" class="Magento\Catalog\Ui\Component\Listing\Columns\AttributeSetText" sortOrder="41">
            <settings>
                <label translate="true">AttributeSetText</label>
                <visible>false</visible>
            </settings>
        </column>
        <column name="status" component="Magento_Ui/js/grid/columns/select" sortOrder="50">
            <settings>
                <options class="Magento\Catalog\Model\Product\Attribute\Source\Status"/>
                <filter>select</filter>
                <dataType>select</dataType>
                <label translate="true">Status</label>
            </settings>
        </column>
        <column name="status_text" class="Magento\Catalog\Ui\Component\Listing\Columns\StatusText" sortOrder="51">
            <settings>
                <label translate="true">StatusText</label>
                <visible>false</visible>
            </settings>
        </column>
        <column name="type_id" component="Magento_Ui/js/grid/columns/select" sortOrder="60">
            <settings>
                <options class="Magento\Catalog\Model\Product\Type"/>
                <filter>select</filter>
                <dataType>select</dataType>
                <label translate="true">Type</label>
            </settings>
        </column>
        <column name="sku" sortOrder="70">
            <settings>
                <filter>text</filter>
                <label translate="true">SKU</label>
            </settings>
        </column>
        <column name="price" class="Magento\Catalog\Ui\Component\Listing\Columns\Price" sortOrder="80">
            <settings>
                <addField>true</addField>
                <filter>textRange</filter>
                <label translate="true">Price</label>
            </settings>
        </column>
    </columns>
</listing>

Once you create the above file you need to run the following command:
bin/magento cache:flush

And that’s it, you can add products to custom link type like the following screenshot:

We hope this blog may be understandable and useful to you. You can email us at mage2developer@gmail.com if we missed anything or want to add any suggestions. We will respond to you as soon as possible. Happy to help 🙂