问题
I have a .net4.5 web application project that uses SQL server spatial datatype.
Works perfectly locally on development machine, but when deployed to application server I get the following error when trying to run queries on table with spatial data:
System.InvalidOperationException: DataReader.GetFieldType(5) returned null.
I found out that if SQLServer is not installed on the server, there is no support for spatial data types.
Therefore I installed the nuget package to my project:
Install-Package Microsoft.SqlServer.Types
This added references to Microsoft.SqlServer.Types and created a SqlServerTypes folder that contained some dlls.
After re-deploying the project to the server, it still doesn't work (same error).
The instructions from the nuget package say that I must add the following line to the applciaion_start event:
SqlServerTypes.Utilities.LoadNativeAssemblies(AppDomain.CurrentDomain.BaseDirectory);
I have tried doing this but I am getting squiggly blue line under SqlServerTypes with the error "SqlServerTypes is not declared" in Visual Studio.
I have tried adding
Imports Microsoft.SqlServer.Types
but there is no SqlServerTypes namespace or class.
回答1:
The nuget package Microsoft.SqlServer.Types is only for c# projects.
You can modify the class to be compatible with vb.net projects.
Install support into your project using:
Install-Package Microsoft.SqlServer.Types
Locate the following file:
/SqlServerTypes/Loader.cs
Convert the code in Loader.cs to vb (you can do this with an online converter) and save the file as: Loader.vb
Now you will be able to access the SqlServerTypes namespace from your project.
来源：https://stackoverflow.com/questions/23565095/sqlserver-spatial-datareader-getfieldtype-returned-null