选择行阻止取消选择

Created: November-22, 2018

默认行为是在单击两次时取消选择行。在某些用例中，你可能希望禁用此取消选择行为。

注意

table.deselectItem(item) 方法将强制取消选择一个项目。这适用于 item 或 index（当使用 items 数组时）作为参数。

<!DOCTYPE html>
<html>  
  <head>
    <base href="https://polygit.org/polymer+:master/iron-data-table+Saulis+:master/components/">
    <link rel="import" href="polymer/polymer.html">
    
    <script src="webcomponentsjs/webcomponents-lite.min.js"></script>
   
    <link rel="import" href="iron-ajax/iron-ajax.html">
    <link rel="import" href="paper-button/paper-button.html">
    
    <link rel="import" href="iron-data-table/iron-data-table.html">
    <link rel="import" href="iron-data-table/default-styles.html">
  </head>
  <body>
    <x-foo></x-foo>
    <dom-module id="x-foo">
      <template>
        <style>
        </style>
        [[_computeSelectedStr(selectedItem)]]

        <iron-ajax
            auto
            url="https://saulis.github.io/iron-data-table/demo/users.json" 
            last-response="{{users}}"
            >
        </iron-ajax>
        <iron-data-table id="grid"
                         selection-enabled
                         on-deselecting-item="_deselecting"
                         items="[[users.results]]"
                         selected-item="{{selectedItem}}"
                         >
          <data-table-column name="Picture" width="50px" flex="0">
            <template>
              <img src="[[item.user.picture.thumbnail]]">
            </template>
          </data-table-column>
          <data-table-column name="First Name">
            <template>[[item.user.name.first]]</template>
          </data-table-column>
          <data-table-column name="Last Name">
            <template>[[item.user.name.last]]</template>
          </data-table-column>
          <data-table-column name="Email">
            <template>[[item.user.email]]</template>
          </data-table-column>
        </iron-data-table>

      </template>
      <script>
        (function(){
              'use strict';
          Polymer({
            is: 'x-foo',
            observers: [
              '_selectedItemChanged(selectedItem)' ,
            ],
            _selectedItemChanged: function(ob) {
              console.log('selectedItem', ob);
            },
            _computeSelectedStr: function(ob) {
              return JSON.stringify(ob);
            },
            _deselecting: function(e) {
              e.preventDefault();
            }
          });
        })();
      </script>
    </dom-module>
  </body>
</html>