SqlGeometry is a spatial data type introduced in SQL Server 2008 (R2). It can be found in the Microsoft.SqlServer.Types namespace. This is a special data type and not one of the standard SqlDbTypes (enum) datatypes. So – if you have to write (save) this particular value (a SqlGeometry value) along with a set of other database values, what specific SqlParameter should you use?

In other words, if you are constructing a list of SqlParameters (to pass into your SqlCommand), how can you tag along a SqlGeometry data type without offending the database? You can do this in two steps”:

1. Set the SqlDbType to UDT (User Defined Type)
2. Set the UdtTypeName to geometry

This is illustrated in the code snippet below:

 SqlCommand sqlCmd = cmd as SqlCommand;
  for (int i = 0; i < parameterValues.Count; i++)
  {
   SqlDbType dbType = GetDbType(parameterValue.DataType); // This needs to return SqlDbType.UDT for your Geometry data type
   SqlParameter sqlPrm = sqlCmd.Parameters.Add(paramName, dbType);//Step 1:This dbType should be SqlDbType.UDT
             

        // handle the geometry type here
         if (dbType == SqlDbType.Udt)
         {
               sqlPrm.UdtTypeName = "geometry"; // Step 2: Set this to "geometry" - now we can treat this 

                                                like any other SqlParameter even though it's datatype is SqlGeometry
              }
              SqlParameter sqlPrm = sqlCmd.Parameters.Add(paramName, dbType);
           }

Summary

Even though SqlGeometry represents a non-standard SqlDbType, one can simply treat it as a User Defined Type (UDT) with its UdtTypeName set to geometry. This allows us to treat the resulting parameter as a regular SqlParameter.