LINQPad FAQ

FAQ Categories:

Querying

Why does LINQPad pluralize table and child association properties? Can I switch this off?

Pluralizing child association properties (while keeping parent associations singular) makes for the most natural queries and is what Visual Studio does by default in building typed DataContexts.

To switch off pluralization, uncheck the "Pluralize" option when adding the database connection. (If the connection has already been created, right-click it to edit the connection properties).

Why does LINQPad capitalize column names? Can I switch this off?

LINQPad capitalizes property names to avoid collisions with C# keywords. To switch this off, uncheck the "Capitalize" option when creating the database connection (or right-click to edit an existing connection).

Why is LINQPad case-sensitive? SQL isn't!

LINQPad's case-sensitivity depends on which language you select in the Language dropdown. If you want case-insensitivity, choose 'VB' instead of 'C#' (and then remember the underscores with multi-line queries). On a tangential point, SQL Server does treat table and columns names case-sensitively if the database has a case-sensitive collation.

How do I display the results of multi-statement snippets?

This is explained in the samples inside LINQPad - work through the "5-Minute Induction".

Why does LINQPad use LINQ to SQL under the covers, rather than Entity Framework?

LINQ to SQL is faster with large schemas and in most cases, emits better SQL. You can, however, use EF with EDMs that you define yourself. For querying SQLite, MySQL and Oracle (via the optional plug-in), LINQPad uses Matt Warren's IQueryable toolkit.

Can I query XML data sources as well as SQL tables?

Certainly - click here for a simple example. There are a whole lot more examples in the "Samples" tree, under C# 5.0 in a Nutshell, Chapter 10.

I've bought the LINQPad Premium edition and want to write cross-database queries. How do I do this?

There are two ways to do this. The simplest is the drag-and-drop approach: hold down the Ctrl key while dragging additional databases from the Schema Explorer to the query editor. To access those additional databases in your queries, use database.table notation, e.g., Northwind.Regions.Take(100). The databases that you query must reside on the same server.

The second approach is to list the extra database(s) that you want to query in the connection properties dialog. This dialog also lets you choose databases from linked servers. Here's how to proceed:

  1. Add a new LINQ to SQL connection.
  2. Choose Specify New or Existing Database and choose the primary database that you want to query.
  3. Click the Include Additional Databases checkbox and pick the extra database(s) you want to include. You can also choose databases from linked servers in this dialog.

I'm referencing a custom assembly that reads settings from an application configuration file (app.config). Where should I put my application config file so that LINQPad queries will pick it up?

Create a file called linqpad.config in the same folder as LINQPad.exe and put your configuration data there. Don't confuse this with linqpad.exe.config:

Autocompletion and Premium Edition Licensing

I understand that a single-user autocompletion license can activate up to three computers at once. Once I've hit this limit, can I transfer a license from one computer to another?

Yes - you can make up to 6 transfers over a 12-month period (pro-rata for multi-user licenses). To do this, choose 'Remove Autocompletion License' from the Help menu. If you forget, you can remotely deactivate unused machines.

I'm always reformatting and reinstalling Windows. When I reactivate LINQPad's autocompletion, will it eat up an activation?

In most cases, LINQPad won't blink an eye if you keep the same hardware. (If there's any problem, you'll be able to remotely release the old machine's activation).

Can I activate virtual machines?

Sure - right now a single-user license gives you three transferrable virtual activations in addition to your three real activations (pro-rata for multi-user licenses). Virtual activations are locked to both the virtual and host machine, and are valid for Microsoft Virtual PC, Hyper-V, Azure Virtual Machines and VMWare Server & Workstation.

If I buy a 2-user license, will I get 6 activations?

Yes.

I have a team or Enterprise license and want to automate the rollout of LINQPad. Is there any way to activate LINQPad via the command-line?

Yes:

LINQPad.exe -activate=YOUR-ACTIVATION-CODE

Or, to activate all users:

LINQPad.exe -activateall=YOUR-ACTIVATION-CODE

If you are using the LINQPad installer (LINQPad4Setup.exe), you can activate LINQPad as part of installation by calling LINQPad4Setup with the /activate= switch or the /activateall= switch. LINQPad4Setup.exe also supports the /silent switch for automated installation. If you use the /silent switch, you can specify /mergetasks="lprunpath" to instruct the setup to add LINQPad's folder to the PATH environment variable - this is useful if you intend to use the command-line utility (lprun).

My machine has no Internet connectivity. Is there any way to do an offline activation?

Yes, with a few manual steps.

The developers in my company work in three different cities. Are the Team and Enterprise licenses valid over multiple sites?

Yes - you can use a single Team or Enterprise license in up to ten different locations. A location is defined as a usual place of business.

I've lost my activation code. Can I retrieve it?

Click here to retrieve lost activation codes.

I live in a country that doesn't support PayPal (Nigeria, Iran). What do I do?

The payment page now allows you to pay directly via credit card (without PayPal). If you still experience difficulties, please contact customer support.

Security

I notice LINQPad automatically patches itself when an update is released. How does it ensure updates are authentic and have not been tampered with in transit? My company is anal about security!

LINQPad will accept an update only if the assembly has a valid signature - and the public key matches that of the original assembly.

If I save a connection that uses SQL Authentication, does LINQPad store the password in plain text?

Of course not! LINQPad encrypts the password securely using the Windows Data Protection API.

Customization & Extensibility

What extensibility points does LINQPad provide?

First, you can reference custom assemblies and import custom namespaces - go to Query Properties (F4).

You can also control what fields/properties of your custom types are displayed via LINQPad's Dump method, by implementing the following interface:

namespace LINQPad
{
   public interface ICustomMemberProvider
   {
      // Each of these methods must return a sequence
      // with the same number of elements:
      IEnumerable<string> GetNames();
      IEnumerable<Type>   GetTypes();
      IEnumerable<object> GetValues();
   }	
}

Note that you don't have to reference the LINQPad assembly in order to implement this interface. Instead, you can copy and paste this interface definition into your target application - as long as it's defined in the LINQPad namespace, LINQPad will recognize the interface via "duck-typing".

LINQPad also allows you to write custom Data Context Drivers and custom visualizers.

Will LINQPad let me run multithreaded code and Parallel LINQ Queries?

Yes. LINQPad also explicitly supports C# 5.0's asynchronous functions, Reactive Extensions and Microsoft DataFlow.

I'm using LINQPad in a presentation. Can I make the query text bigger? And can I use my cordless presenter?

Yes and yes. To adjust the font size, use Control+MouseWheel, or Control+Plus / Control+Minus. (You can also adjust your Windows font size - LINQPad is fully DPI-aware.)

To use a cordless presenter, go to Edit | Preferences and in the 'Advanced' tab, enable presentation mode. You can then use the Logitech Cordless Presenter to:

You can make a query display a PowerPoint slide by entering the following statement into the query:

// Second argument = slide number to start at
PowerPoint.ShowSlide (@"c:\docs\MyPresentation.ppt", 1);

Note that you must install the PowerPoint Viewer for this to work (even if you have already installed the full-blown PowerPoint). And good luck with your presentation!

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