通过 for 循环中的函数调用时，Google 地图无法正确呈现

Question

我正在 ASP.NET MVC Core 中创建一个项目，我正在尝试创建一个带有坐标的列表并在其旁边显示一个谷歌地图图钉。

地图正在渲染，但显示为灰色/空白。

我的地图列表代码

<table class="table">

    <thead>

        <tr>

            <th>

                @Html.DisplayNameFor(model => model.Coordinates)

            </th>

        </tr>

    </thead>

    <tbody>

        @{

            int count = 0;

        }

        @foreach (var item in Model)

        {

            <tr>

                <td>

                    <div id="@count" style="height:400px;width:700px;"></div>

                    <script type="text/javascript">myMap('@count', @item.Coordinates)</script>

                    @Html.DisplayFor(modelItem => item.Coordinates)

                </td>

                <td>

                    <a asp-action="Edit" asp-route-id="@item.Coordinates">Edit</a> |

                    <a asp-action="Details" asp-route-id="@item.Coordinates">Details</a> |

                    <a asp-action="Delete" asp-route-id="@item.Coordinates">Delete</a>

                </td>

            </tr>

            count++;

        }

    </tbody>

</table>

我正在使用的 JS 函数。head它与我的 API 密钥一起加载

    <script type="text/javascript">

        function myMap(divId, coord) {

            var myCenter = new google.maps.LatLng(coord);

            var mapProp = { center: myCenter, zoom: 12, scrollwheel: false, draggable: true, mapTypeId: google.maps.MapTypeId.ROADMAP };

            var map = new google.maps.Map(document.getElementById(divId), mapProp);

            var marker = new google.maps.Marker({ position: myCenter });

            marker.setMap(map);

        }

    </script>

这是我的结果。

我无法弄清楚我做错了什么，我一直在寻找但找不到任何答案。任何帮助表示赞赏！

Answer 1

确保在加载 Google Maps API 后初始化地图。要做到这一点，只需将callbackgoogle 的 url 的一部分指向将处理它的函数（参见下面的示例）。同样，正如 Lee 在他的评论中所说，不要使用数字作为元素 ID。Lee 关于使用前缀的建议很准确，您应该考虑使用它。<table class="table">&nbsp; &nbsp; <thead>&nbsp; &nbsp; &nbsp; &nbsp; <tr>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <th>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; @Html.DisplayNameFor(model => model.Coordinates)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </th>&nbsp; &nbsp; &nbsp; &nbsp; </tr>&nbsp; &nbsp; </thead>&nbsp; &nbsp; <tbody>&nbsp; &nbsp; &nbsp; &nbsp; @{&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; int count = 0;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; @foreach (var item in Model)&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <tr>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <div class="map" id="map_@count" style="height:400px;width:700px;" data-coord="@item.Coordinates"></div>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <!-- REMOVED script here and added more data to the div element above -->&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; @Html.DisplayFor(modelItem => item.Coordinates)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <a asp-action="Edit" asp-route-id="@item.Coordinates">Edit</a> |&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <a asp-action="Details" asp-route-id="@item.Coordinates">Details</a> |&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <a asp-action="Delete" asp-route-id="@item.Coordinates">Delete</a>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </td>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </tr>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; count++;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; </tbody></table><script>&nbsp; // this function will be called by google's api once loaded&nbsp; function loaded() {&nbsp; &nbsp; // assuming each map container has a class "map",&nbsp; &nbsp; let maps = document.querySelectorAll('.map');&nbsp; &nbsp; maps.forEach(map => initMap(map));&nbsp; }&nbsp; function initMap(map) {&nbsp; &nbsp; var myCenter = new google.maps.LatLng(map.dataset.coord); // retrieving coords from data attribute&nbsp; &nbsp; var mapProp = { center: myCenter, zoom: 12, scrollwheel: false, draggable: true, mapTypeId: google.maps.MapTypeId.ROADMAP };&nbsp; &nbsp; var map = new google.maps.Map(map, mapProp);&nbsp; &nbsp; var marker = new google.maps.Marker({ position: myCenter });&nbsp; &nbsp; marker.setMap(map);&nbsp; }</script><script src="https://maps.googleapis.com/maps/api/js?key=APIKEY&callback=loaded"></script>编辑：看看下面的片段。我之前没有发现坐标必须作为数字传递。let maps = document.querySelectorAll('.map')function loaded() {&nbsp; maps.forEach(map => initMap(map))}function initMap(element) {&nbsp; let xy = element.dataset.coords.split(',').map(a => parseFloat(a))&nbsp; let center = new google.maps.LatLng(xy[0], xy[1])&nbsp; let props = { center: center, zoom: 12, scrollwheel: false, draggable: true, mapTypeId: google.maps.MapTypeId.ROADMAP };&nbsp; let map = new google.maps.Map(element, props);&nbsp; let marker = new google.maps.Marker({ position: center });&nbsp; marker.setMap(map);}.map {&nbsp; width: 400px;&nbsp; height: 400px;&nbsp; background: yellow;&nbsp; margin-bottom: 15px;}<!-- The British Museum --><div class="map" data-coords="51.5145532,-0.1167918"></div><!-- Castello Sforzesco --><div class="map" data-coords="45.4636261,9.1714131"></div><!-- Nordscheleife --><div class="map" data-coords="50.3341015,6.9404738"></div><script src="https://maps.googleapis.com/maps/api/js?key=&callback=loaded" async defer></script>

Answer 2

也许你在地图初始化之前就得到了坐标？尝试在 OnMapReady 事件中调用 api