Angular.js linq.js Where filter不能正常工作

Angular.js linq.js Where filter not working properly

本文关键字：js 常工作 工作 不能 linq Where filter Angular      更新时间：2023-09-26

我在AngularJs中使用linq.js，我在很多地方使用，它的工作很好，现在我在不同的地方使用，它不适合我。不工作意味着我没有达到预期的结果，它总是显示{}。请看看下面的代码，如果我做错了什么。

var app = angular.module('testApp', ['angular.filter', 'angular-linq', 'ngSelect2']);
    app.controller('testController', function ($scope, $http, $timeout, $q, $linq){
    $scope.Vendors = 
    [
      {VendorId:"VND001", VendorName:"Pharma Plus Pharmacy", Address:"Bahawalpur"},
      {VendorId:"VND001", VendorName:"Pakistan Pharma", Address:"Bahawalpur"}
    ];
    $scope.InvoiceItems = 
    [
     {
        VendorId:"VND001", 
        ItemName:"Gold Set Jewellery", 
        ItemDesc:"Some Description", 
        Cost:280.50, 
        Quantity:50 
     },
     {
        VendorId:"VND001", 
        ItemName:"First Class HandWatch", 
        ItemDesc:"Some Description", 
        Cost:100.50, 
        Quantity:50 
     },
     {
        VendorId:"VND002", 
        ItemName:"Gold Set Jewellery", 
        ItemDesc:"Some Description", 
        Cost:280.50, 
        Quantity:50 
     },
     {
        VendorId:"VND002", 
        ItemName:"First Class HandWatch", 
        ItemDesc:"Some Description", 
        Cost:100.50, 
        Quantity:50 
     },
    ];
    $scope.totalAmount = function(vendorId){
       return $linq.Enumerable().From($scope.InvoiceItems).Where("x => x.VendorId =="+vendorId).Select(function(x){
          return (+x.Cost)*x.Quantity;
       }).Sum();
    }
  }
}

请看下面的html

<div class="row" ng-app="testApp">
  <div class="col-xs-12" ng-controller="testController" ng-init="initializeDefault()">
    <div ng-repeat="v in Vendors">
        <div>{{ v.VendorId }}</div>
        <div>{{ v.VendorName }}</div>
        <div>{{ v.Address }}</div>
        <div>{{ totalAmount(v.VendorId) }}</div>
    </div>
  </div>
</div>

请尽快回复。

我看到的第一个问题是where子句中的谓词格式错误。

x.VendorId是一个字符串，您试图将其与vendorId中传递的字符串进行比较。但是你生成的lambda是:

x => x.VendorId ==VND001

将不会产生任何结果。

相反，你需要生成:

x => x.VendorId == 'VND001'

您的查询应该是(使用更紧凑的lambda语法):

$linq.Enumerable().From($scope.InvoiceItems)
    .Where("$.VendorId == '" + vendorId + "'")
    .Select("+$.Cost * $.Quantity")
    .Sum();

但是，如果您预先组合这些查询并将总和作为查询的一部分，而不是单独的查询，则会更好。你必须把这两个数组连接起来。

$scope._vendors = ...;
$scope._invoiceItems = ...;
$scope.VendorQuery = function() {
    return $linq.Enumerable().From($scope._vendors)
        .GroupJoin($scope._invoiceItems, "$.VendorId", "$.VendorId",
            "{ Id: $.VendorId, Name: $.VendorName, Address: $.Address, "
            + "Total: $$.Sum('+$.Cost * $.Quantity') }")
        .ToArray();
}

然后绑定到视图:

<div ng-repeat="v in VendorQuery()">
    <div>{{ v.Id }}</div>
    <div>{{ v.Name }}</div>
    <div>{{ v.Address }}</div>
    <div>{{ v.Total }}</div>
</div>
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