Polymer如何绑定paper-input值到iron-ajax

Question

以下是我的页面代码

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>GP and Practice search</title>   <!-- Scripts -->
    <script src="bower_components/webcomponentsjs/webcomponents-lite.js"></script>
    <link rel="import" href="elements/elements.html" />
    <link rel="stylesheet" type="text/css" href="Styles/styles.css" />
    <link rel="stylesheet" type="text/css" href="Styles/home.css"/>
    <!-- google fonts definitions -->
    <link href='http://fonts.googleapis.com/css?family=Roboto:400,700' rel='stylesheet' type='text/css'>

</head>

<body unresolved class="fullbleed layout vertical">
    <dom-module id="page-scafolding">
        <template>
            <paper-drawer-panel elevation="1">
                <paper-header-panel main mode="waterfall-tall">
                    <paper-toolbar id="mainToolbar">
                        <paper-icon-button id="paperToggle" icon="menu" paper-drawer-toggle></paper-icon-button>
                        <span class="flex"></span>
                        <paper-icon-button icon="search" on-tap="srchandler" id="srchandler"></paper-icon-button>
                        <input type="text" id="searchText" hidden$="{{hideSearch}}" onkeypress="handleKeyPress(event);" />
                        <div class="middle paper-font-display2 app-name ident">Search</div>
                    </paper-toolbar>
                    <paper-material elevation="1" class="contentContainer" >
                        <div id="Content" >
                            <span>
                                <paper-input id="searchCriteria" 
                                             class="searchBox" 
                                             label="Code or name of the GP or Practice you are looking for?"  />
                            </span>
                            <div style="text-align:center; padding:10px;">
                                <paper-button tabindex="0" raised="true" class="colorful" on-click="searchPractice">Search for Practice</paper-button>
                                <paper-button tabindex="0" raised="true" class="colorful" on-click="searchPractice">Search for GP</paper-button>
                            </div>
                            <div id="SearchResult">
                                <template is="dom-repeat" items="{{data}}">
                                    <p><span>{{item.Name}}</span> (<span>{{item.PracticeCode}}</span>)</p>
                                </template>
                            </div>
                        </div>
                    </paper-material>
                    <iron-ajax id="GPSearch"
                               url="/GPPractices.ashx"
                               handle-as="json"
                               last-response="{{data}}"
                               params='{{ajaxParams}}'
                               handleerror="handleError">

                    </iron-ajax>
                </paper-header-panel>
            </paper-drawer-panel>
        </template>
        <script>
            Polymer({
                is: "page-scafolding",
                ready: function () {
                    this.hideSearch = true;
                    this.$.searchText.keyup(function (e) {
                        alert('off to search for something!');
                    });
                },
                ajaxParams: {
                    type: String,
                    computed: 'buildSearchRequest();'
                },
                buildSearchRequest: function () {
                    return {
                        Command: 'Search',
                        Criteria: this.$.searchCriteria
                    }
                },
                srchandler: function () {
                    // search for contents of search box is showing, otherwise show it.
                    if (!this.hideSearch)
                    {
                        alert('off to search for something!');
                    }
                    else {
                        this.hideSearch = !this.hideSearch;
                        if (!this.hideSearch) {
                            this.$.searchText.focus();
                        }
                    }
                },
                searchPractice: function () {
                    try {           
                        this.$.GPSearch.generateRequest();
                    }
                    catch (e) {
                        alert("Whoops! " + e.message);
                    }

                },
                handleError: function (request, error) {
                    alert('Whoops! ' + error);
                }
            });
        </script>
    </dom-module>

    <page-scafolding />
</body>
</html>

我收到了 ajax 呼叫，并且正在呼叫 GPPractices.ashx。我要做的是将两个参数传递给此页面。一个是 Command，其值为 'search'，另一个参数是输入到名为 searchCriteria 的 paperInput 中的任何内容。

问题是没有得到两个参数Command 和Criteria。我得到一个空的 QueryString，它看起来不像是曾经调用过 buildSearchRequest。

那么我怎样才能得到它，如果我在纸输入中输入 say 'abba'，查询字符串应该是

Command=search&criteria=abba

Answer 1

我让它工作了。不确定这是否是正式的最佳方式，但通过将 searchPractice 函数的代码更改为以下 - 发送正确的 QueryString 并且搜索有效。

            searchPractice: function () {
                try {
                    this.$.GPSearch.params = {
                        Command: 'Search',
                        Criteria: this.$.searchCriteria.value
                    };
                    this.$.GPSearch.generateRequest();
                }
                catch (e) {
                    alert("Whoops! " + e.message);
                }

            }

Answer 2

我在下面放置了您代码的简化工作版本。以下是一些注意事项：

这个声明

ajaxParams: {
  type: String,
  computed: 'buildSearchRequest();'
},

是一个属性定义，必须进入 properties 对象。

回调值如
```
computed: 'buildSearchRequest();'
```
看起来像函数，但它们不是实际代码，不需要尾随 ;
您的 computed 函数需要有一个参数来告诉它何时重新计算。我将其修改为如下所示：
```
computed: 'buildSearchRequest(searchCriteria)'
```
并且我将 searchCriteria 绑定到输入 value。
Polymer 代码中的事件处理程序使用 on- 表示法，因此
```
onkeypress="handleKeyPress(event);"
```
应该是
```
on-keypress="handleKeyPress"
```
iron-ajax 错误通知是通过名为 error 的事件发出的，所以
```
handleerror="handleError"
```
应该是
```
on-error="handleError"
```
我添加了 stringify 位和参数的输出，这样您就可以看到它在您键入时进行计算，这对于您的用例来说不是必需的。
只有极少数元素在 HTML 中是 void（不需要结束标记）。你应该避免做 <tag-name/> 因为它最终会引起麻烦。

直播：http://jsbin.com/sorowi/edit?html,output

    <dom-module id="page-scafolding">
      <template>

        <paper-input 
          label="Code or name of the GP or Practice you are looking for?" 
          value="{{searchCriteria}}">
        </paper-input>

        <br>

        <div style="text-align:center; padding:10px;">
          <paper-button tabindex="0" raised="true" style="background-color: lightblue;" on-click="searchPractice">Search for Practice</paper-button>
        </div>

        <iron-ajax id="GPSearch"
                   url="/GPPractices.ashx"
                   handle-as="json"
                   last-response="{{data}}"
                   params="{{ajaxParams}}"
                   on-error="handleError">   
        </iron-ajax>

        <br><br>
        ajaxParams: <span>{{stringify(ajaxParams)}}</span>

        <div id="SearchResult">
          <template is="dom-repeat" items="{{data}}">
            <p><span>{{item.Name}}</span> (<span>{{item.PracticeCode}}</span>)</p>
          </template>
        </div>

      </template>
      <script>
        Polymer({

          is: "page-scafolding",

          properties: {
            ajaxParams: {
              type: String,
              computed: 'buildSearchRequest(searchCriteria)'
            }
          },

          stringify: JSON.stringify, 

          buildSearchRequest: function (criteria) {
            return {
              Command: 'Search',
              Criteria: criteria
            };
          },

          searchPractice: function () {
            this.$.GPSearch.generateRequest();
          },

          handleError: function(e) {
            alert('Whoops! ' + e.detail);
          }

        });
      </script>
  </dom-module>

HTH

Polymer如何绑定paper-input值到iron-ajax

Polymer how to bind paper-input value to iron-ajax

javascript

css

polymer