Mryntu

I am setting some values in multi-select to be disabled based on some condition

This is how I am declaring my UI component

<field name="category_option">
 <argument name="data" xsi:type="array">
 <item name="options" xsi:type="object">MycompanyStoresModelCategoryAttributeSourceCategoryOptions</item>
 <item name="config" xsi:type="array">
 <item name="dataType" xsi:type="string">text</item>
 <item name="label" translate="true" xsi:type="string">Category Option</item>
 <item name="formElement" xsi:type="string">multiselect</item>
 <item name="source" xsi:type="string">category_option</item>
 <item name="sortOrder" xsi:type="number">60</item>
 <item name="dataScope" xsi:type="string">category_option</item>
 <item name="validation" xsi:type="array">
 <item name="required-entry" xsi:type="boolean">true</item>
 </item>
 </item>
 </argument>
 </field>

And passing values using

public function toOptionArray()
 
 $categories = $this->_helper->getTestCategoryOptions();
 $testArr = [];
 foreach($categories as $category)
 $testArr = array_merge($testArr,$category);
 
 foreach($testArr as $test)
 switch($test['label'])
 case 'case1': 
 $result[] = ['value' => $test['label'], 'label' => strtoupper($test['label']), 'disabled'=>""];
 break;
 case 'Food City':
 $result[] = ['disabled'=>'disabled','value' => $test['label'], 'label' => strtoupper($test['label'])];
 break;
 case 'case2':
 $result[] = ['value' => $test['label'], 'label' => strtoupper($test['label'])];
 break;
 case 'case3':
 $result[] = ['value' => $test['label'], 'label' => strtoupper($test['label'])];
 break;
 case 'case4':
 $result[] = ['value' => $test['label'], 'label' => strtoupper($test['label'])];
 break;
 default:
 $result[] = ['value' => $test['value'], 'label' => $test['label']];
 
 
 return $result;
 

in above code I even tried 'disabled'=>'disabled' , 'disabled'=>'true' but no effect on UI component

The function that outputs the option tag is _optionToHtml in vendor/magento/framework/Data/Form/Element/Multiselect.php

It doesn't look for a disabled attribute, but you can trick it into outputting the attribute by abusing the option 'title' or 'style' attributes. e.g.

 case 'Food City':
 $result[] = ['style'=>'" disabled="disabled"','value' => $test['label'], 'label' => strtoupper($test['label'])];
 break;