A simple LINQPad query host

I am a big fan of LINQPad. I use LINQPad routinely during my work to test small, incremental ideas. I used it so much so that I bough myself a premium license.

I always wish I can run queries designed in LINQPad in my own program. Before 4.52.1 beta, there was only a command line interface. In LINQPad v4.52.1 beta, there is finally a Util.Run method that allows me to run LINQPad queries in my own process. However, I felt that I did not have sufficient control on how I can dump the results. So I decided to write a simple host myself.

As in the example below, a .linq file starts with an xml meta data section followed by a blank line and then the query or the statements.

<Query Kind="Expression">
  <Reference>&lt;RuntimeDirectory&gt;\System.Web.dll</Reference>
  <Reference>&lt;ProgramFilesX86&gt;\Microsoft ASP.NET\ASP.NET MVC 4\Assemblies\System.Web.Mvc.dll</Reference>
  <Namespace>System.Web</Namespace>
  <Namespace>System.Web.Mvc</Namespace>
</Query>
 
HttpUtility.UrlEncode("\"'a,b;c.d'\"")

The article “http://www.linqpad.net/HowLINQPadWorks.aspx” on the LINQPad website gives me good information on how to compile and execute queries.  LINQPad uses CSharpCodeProvider (or VBCodeProvider) to compile queries. Although I was tempted to use Roslyn like ScriptCS, I decided to use CSharpCodeProvider to ensure compatible with LINQPad.

We only need 3 lines of code to the LINQPad host:

using LINQPadHost;
...
string file = @"C:\Users\lichen\Documents\LINQPad Queries\ServerUtility.linq";
Host host = new Host();
host.Run<JsonTextSerializer>(file);

As I mentioned at the beginning. I would like to control the dumping of the results. JsonTextSerializer is one of the three serializers that I supplied. The other two serializers are IndentTextSerializer and XmlTextSerializer. Personally, I found that the JsonTextSerializer and IndentTextSerializer the most useful.

The source code could be found here.

Examples could be found here.