如何返回一个KML内容

本文关键字：一个 KML 内容 返回 何返回 | 更新日期: 2023-09-27 18:05:30

我正在尝试烹饪一个连接到我的DB的web api，获取一些地理数据，然后返回一个将由网页消费的KML内容(在google maps iframe/div上显示信息)。

我正在使用sharpKML(我不知道它是否是正确的选择):

public class KmlController : ApiController
{
    public HttpResponseMessage Get()
    {
        Point point = new Point();
        point.Coordinate = new Vector(37.42052549, -122.0816695);
        Placemark placemark = new Placemark();
        placemark.Name = "Somewhere";
        placemark.Geometry = point;
        Kml kml = new Kml();
        kml.Feature = placemark;
        return Request.CreateResponse(HttpStatusCode.OK, kml, new XmlMediaTypeFormatter(), "application/vnd.google-earth.kml+xml");
    }
}

但是当我调用http://something.on.my.lan/api/kml时，我得到了这个异常:

系统。InvalidOperationException:'ObjectContent ' 1'类型未能序列化内容类型'application/vnd.google-earth.kml+xml '的响应体;charset = utf - 8"。

我错过了什么?

<

解决方案/strong>

不幸的是，正如这个答案中所说，即使我设法动态地创建了一个KML内容，它也不会显示在地图上，因为URL必须由Google公开访问(出于缓存目的)。我必须改变方法

如何返回一个KML内容

先试试这个，我想知道是否有任何对象的序列化问题:

private string SerializeObject<T>(this T toSerialize)
{
    XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType());
    StringWriter textWriter = new StringWriter();
    xmlSerializer.Serialize(textWriter, toSerialize);
    return textWriter.ToString();
}

public class KmlController : ApiController
{
    public string Get()
    {
        Point point = new Point();
        point.Coordinate = new Vector(37.42052549, -122.0816695);
        Placemark placemark = new Placemark();
        placemark.Name = "Somewhere";
        placemark.Geometry = point;
        Kml kml = new Kml();
        kml.Feature = placemark;
        return SerializeObject<Kml>(kml);;
    }
}

如果失败，我建议您参考序列化文档，以便您可以找到哪个对象没有正确序列化。

http://msdn.microsoft.com/en-us/library/system.serializableattribute.aspx

这是为我工作…

    public static byte[] SerializeKml(this KmlFile kml)
    {
        var serializer = new Serializer(); 
        serializer.Serialize(kml.Root); 
        var str = serializer.Xml;
        var bytes = new byte[str.Length * sizeof(char)];
        Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
        return bytes;
    }
    public ActionResult GetKml()
    {
        Placemark placemark = new Placemark
        {
            Geometry = new Point { Coordinate = new Vector(-13.163959, -72.545992) },
            Name = "Machu Picchu",
        };
        var kml = KmlFile.Create(placemark, false);
        var fcResult = new FileContentResult(kml.SerializeKml(), "application/vnd.google-earth.kml+xml") { FileDownloadName = "MachuPicchu.kml" };
        return fcResult;
    }
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