異常：不存在從對象類型System.Data.Spatial.DbGeography到已知托管提供程序本機類型的映射

Question

當我嘗試更新數據庫中的地理位置值時，發生異常。

var requestUri = string.Format("http://maps.googleapis.com/maps/api/geocode/xml?address={0}&sensor=false", Uri.EscapeDataString(address));

var request = WebRequest.Create(requestUri);
var response = request.GetResponse();
var xdoc = System.Xml.Linq.XDocument.Load(response.GetResponseStream());

var result = xdoc.Element("GeocodeResponse").Element("result");
var locationElement = result.Element("geometry").Element("location");
var latitude = locationElement.Element("lat");
var longitude = locationElement.Element("lng");
double lat = Double.Parse(latitude.Value);
double lon = Double.Parse(longitude.Value);

var geo = string.Format(CultureInfo.InvariantCulture.NumberFormat, "POINT({0} {1})", lat, lon);

var geoLocation = DbGeography.PointFromText(geo, 4326);
SqlCommand updationCommand = connection.CreateCommand();
updationCommand.CommandText = "Update Communications SET [GeoLocation]=@GeoLoc Where [Id] =@Id";   
updationCommand.Parameters.AddWithValue("@Id", row.Id);                                        
updationCommand.Parameters.AddWithValue("@GeoLoc", geoLocation);
var param2 = updationCommand.CreateParameter();

示例-“從對象類型System.Data.Spatial.DbGeography到已知的托管提供程序本機類型不存在映射。”

Answer 1

使用SqlGeography而不是DbGeography，因為DbGeography設計用於EF。

嘗試

SqlParameter p = new SqlParameter();
p.Name = "@GeoLoc";
p.Value = SqlGeography.Parse(geoLocation.AsText());
p.SqlDbType = SqlDbType.Udt;
p.UdtTypeName = "geography";
updationCommand.Parameters.Add(p);

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