Azure WebApp配置 - 多个VirtualApplications copyIndex无效

Question

在Azure中部署WebApp ARM模板时，我收到以下错误：

  

＆＃39;模板功能＆＃39; copyIndex＆＃39;预计不会在这个位置。该功能只能在指定了副本的资源中使用。＆＃39;

   "resources":[
            {
                "type": "Microsoft.Web/sites/config",
                "name": "[concat(variables('webSiteName'),'/','web')]",
                "apiVersion": "2015-08-01",
                "dependsOn": [
                  "[resourceId('Microsoft.Web/sites', variables('webSiteName'))]"
                ],
                "properties": {
                "alwaysOn": "true",
                "copy": [
                    {
                        "name": "virtualApplications",
                        "count": "[length(parameters('virtualdirectories'))]",
                        "input": {
                            "virtualPath": "[parameters('virtualdirectories')[copyIndex('virtualApplications')].virtualpath]",
                            "physicalPath": "[parameters('virtualdirectories')[copyIndex('virtualApplications')].physicalpath]"
                        }
                    }
                ]
                }

我的参数文件包含虚拟目录..：

 "virtualdirectories": {
        "value": [
            {
                "virtualpath": "vd1",
                "physicalpath": "site\\pd1"
            },
            {
                "virtualpath": "vd2",
                "physicalpath": "site\\pd2"
            }
        ]
    }

任何想法都错了吗？