传单地图和 VB.net-解网

问：

我在尝试从包含 pos lats 和 long 的 xml 文件加载的地图上绘制航点的路线时遇到了扩展问题。传单地图按预期加载，并用标记绘制航点，但似乎不喜欢用多边形线连接它们。有什么想法吗？

运行代码时，我在调试输出中收到以下错误行：“未捕获的 TypeError：无法读取 null 的属性（读取'0'）”，来源：https://unpkg.com/[email protected]/dist/leaflet.js （5）

我尝试了许多不同的方法来重新排序事件以及如何调用函数，但都没有成功。

HTML代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Stamen Terrain Map</title>
    <!-- Leaflet CSS -->
    <link rel="stylesheet" href="https://unpkg.com/[email protected]/dist/leaflet.css" />
    <!-- Leaflet JavaScript -->
    <script src="https://unpkg.com/[email protected]/dist/leaflet.js"></script>
</head>
<body>
    <div id="map" style="height: 500px;"></div>
    <button id="showRouteButton">Show Route</button>

<script>
    var map = L.map('map').setView([0, 0], 2); // Centered on the world map, zoom level 2

    L.tileLayer('https://stamen-tiles-{s}.a.ssl.fastly.net/terrain/{z}/{x}/{y}.jpg', {
        maxZoom: 14,
        attribution: '&copy; <a href="https://stamen.com/">Stamen Design</a> &copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap contributors</a>'
    }).addTo(map);

    // Creating an empty feature group to store the route lines
    var routeLines = L.featureGroup().addTo(map);

    // Function to plot a waypoint on the map
    function plotWaypoint(lat, lng) {
        L.marker([lat, lng]).addTo(map);
    }

    // Function to display the route
    function showRoute(routeCoordinates) {
        if (routeCoordinates.length > 1) {
            // Clear any previous route lines
            routeLines.clearLayers();

            for (var i = 0; i < routeCoordinates.length - 1; i++) {
                var startPoint = routeCoordinates[i];
                var endPoint = routeCoordinates[i + 1];

                // Check if startPoint and endPoint are defined
                if (startPoint && endPoint) {
                    var route = [startPoint, endPoint];
                    L.polyline(route, { color: 'blue' }).addTo(routeLines);
                }
            }
        }
    }
</script>



</body>
</html>

VB.NET 代码：

Dim webView As ChromiumWebBrowser


    Private Sub LoadMap()
        ' Load your HTML file
        Dim htmlFilePath As String = Application.StartupPath & "\WMap.html"
        MsgBox(htmlFilePath)
        ChromiumWebBrowser1.Load(htmlFilePath)
    End Sub

    Private Sub Guna2Button6_Click(sender As Object, e As EventArgs) Handles Guna2Button6.Click
        LoadMap()
    End Sub

    Private Sub Guna2Button7_Click(sender As Object, e As EventArgs) Handles Guna2Button7.Click
        plotwaypointsfromxml()
    End Sub

    Private Sub plotwaypointsfromxml()
        ' Load the XML file
        Dim xmlFile As String = Application.StartupPath & "\Test.xml"
        Dim xmlDoc As New XmlDocument()
        xmlDoc.Load(xmlFile)

        ' Find the navlog element
        Dim navlogNode As XmlNode = xmlDoc.SelectSingleNode("/OFP/navlog")

        If navlogNode IsNot Nothing Then
            Dim routeCoordinates As New List(Of Object)

            ' Loop through each fix element
            For Each fixNode As XmlNode In navlogNode.SelectNodes("fix")
                Dim lat As Double
                Dim lng As Double

                ' Extract latitude and longitude from fix element
                Double.TryParse(fixNode.SelectSingleNode("pos_lat").InnerText, lat)
                Double.TryParse(fixNode.SelectSingleNode("pos_long").InnerText, lng)

                ' Add the waypoint to the routeCoordinates array
                routeCoordinates.Add(New Object() {lat, lng})
            Next

            ' Plot waypoints first
            For Each coord As Object In routeCoordinates
                Dim lat As Double = CDbl(coord(0))
                Dim lng As Double = CDbl(coord(1))
                ChromiumWebBrowser1.ExecuteScriptAsync("plotWaypoint", New Object() {lat, lng})
            Next

            ' Call the JavaScript showRoute function in the WebBrowser control

            ChromiumWebBrowser1.ExecuteScriptAsync("showRoute", New Object() {routeCoordinates})
        End If

    End Sub

JSON vb.net 传单 Cefsharp

答： 暂无答案

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