Q. I'm getting a "can't materialise field [Foo] on model [Bar]" error when I try to load entities.
This may mean you have a field in your entity that doesn't correspond to a database column. If it's a field that's not meant to be persistent, mark it as transient using the TransientAttribute or the designer Transient setting.
This can also occur when the field is of a different data type from the database type: for example if the database is returning a string, but Foo is declared as integer. Look at the InnerException to see if this is the case.
Q. When I open designer files in VS2010, they show up as XML rather than graphical models.
This can occur for two reasons:
1. Visual Studio 2010 has an issue where it tends to remember if a file has ever in its existence been opened as XML, even due to an error, and if so keeps opening it as XML for ever and ever. To fix this, close the solution, open the .csproj or .vbproj in a text editor, find the element for the .lsmodel file, and remove the <SubType>Designer</SubType> subelement.
2. If Visual Studio encounters an error loading LightSpeed, it prompts to disable LightSpeed Visual Studio integration. If you say yes to this, then VS doesn't give you a way to undo it once the error has been fixed. To re-enable LightSpeed, open a Visual Studio command prompt (see below) and run devenv /resetskippkgs.
If this happens immediately on first installation, it may be a UAC issue. It seems that UAC can prevent Visual Studio integration from installing correctly (possibly due to registry virtualisation). Try uninstalling, turning UAC off temporarily, and then reinstalling.
Q. The LightSpeed designer is giving weird errors (e.g. method missing exceptions).
This probably indicates a corrupted installation. Close Visual Studio and go into Control Panel. Look for any installations of "Mindscape LightSpeed" (there may be more than one!) and uninstall all of them. If you used the preview version of the VS2010 designer, also look for "LightSpeed Designer for Visual Studio 2010" (without the 'Mindscape' prefix) and uninstall that. Check in C:\Program Files\Mindscape\LightSpeed to make sure that all files are uninstalled, and check in the GAC to ensure that all Mindscape.LightSpeed.* files have been removed.
Now open a Visual Studio command prompt (see below), run devenv /setup, reinstall LightSpeed and see if the problem recurs.
Q. Visual Studio 2010 is giving me lots of "The type or namespace name 'xxx' could not be found errors," even though I definitely have the LightSpeed DLL referenced.
This is VS2010's ever-so-helpful way of telling you that it has selected the .NET Client Profile as the target framework. Change the target framework to the full profile.
Q. How do I open a Visual Studio command prompt?
Open the Start menu, All Programs.
For VS2008, choose Microsoft Visual Studio 2008 > Visual Studio Tools > Visual Studio 2008 Command Prompt.
For VS2010, choose Microsoft Visual Studio 2010 > Visual Studio Tools > Visual Studio Command Prompt (2010).
(If you are having problems with both VS2008 and VS2010, you will need to open separate command prompts for both versions.)