GeoJSON.Net.Contrib 
Repository for all GeoJSON.Net *.Contrib projects
GeoJSON.Net.Contrib.MsSqlSpatial
Allows conversion from / to Microsoft Sql Server geometry and geography data types.
NuGet package:
Install-Package GeoJSON.Net.Contrib.MsSqlSpatial
Conversion examples:
using GeoJSON.Net.Geometry;
using Microsoft.SqlServer.Types;
using GeoJSON.Net.Contrib.MsSqlSpatial;
// SqlGeometry sample point
SqlGeometry simplePoint = SqlGeometry.Point(1, 47, 4326);
// SqlGeometry -> GeoJSON example
Point point = simplePoint.ToGeoJSONObject<Point>();
// GeoJSON -> SqlGeometry example
SqlGeometry sqlPoint = point.ToSqlGeometry(4326);WKT conversion examples:
using GeoJSON.Net.Contrib.MsSqlSpatial;
using GeoJSON.Net.Geometry;
// LineString from WKT
LineString lineString = WktConvert.GeoJSONObject<LineString>("LINESTRING(1 47,1 46,0 46,0 47,1 47)");
// LineString IGeometryObject from WKT
IGeometryObject lineStringGeom = WktConvert.GeoJSONGeometry("LINESTRING(1 47,1 46,0 46,0 47,1 47)");