Could not load type 'SqlGuidCaster' from assembly Microsoft.Data.SqlClient

[aj-scram]

Recently upgrade project from .net7 to .net8 and immediately ran into this old dotnet/SqlClient#1930

Seems that the root cause is any older version of Microsoft.Data.SqlClient (<5.2.0) than the newest release not playing well with reflection calls loading types/assemblies.

Could we get Microsoft.EntityFrameworkCore.SqlServer to update to use the new version?

[ErikEJ]

Not going to happen, as 5.2 is not LTS and .NET 8 is. You can just add an explicit reference.

[aj-scram]

Then can the dotnet team work internally to backport the fix to a 5.1.6 release? This is a major and long-standing breaking issue for those trying to migrate their projects; it seems unreasonable to me to have us work around it on our end.

[ajcvickers]

We're actually going to revert to an older release for EF Core 9, since we can't take a dependency on a non-LTS version. So EF Core won't depend on anything above 5.1 until at least EF Core 10.

[rasmusrim]

Not going to happen, as 5.2 is not LTS and .NET 8 is. You can just add an explicit reference.

Could I ask you to explain how to do that? Thanks!

[ErikEJ]

@rasmusrim

Add this to your .csproj file that reference the EF Core SQL Server provider:

<PackageReference Include="Microsoft.Data.SqlClient" Version="5.2.0" />

[aj-scram]

Not going to happen, as 5.2 is not LTS and .NET 8 is. You can just add an explicit reference.

Could I ask you to explain how to do that? Thanks!

https://learn.microsoft.com/en-us/nuget/concepts/dependency-resolution#direct-dependency-wins

For doc reference

[amircliper]

@rasmusrim

Add this to your .csproj file that reference the EF Core SQL Server provider:

<PackageReference Include="Microsoft.Data.SqlClient" Version="5.2.0" />

Thank you for sharing this solution! I ran into the same issue and confirmed that adding the following to the .csproj file resolves it:
‍<PackageReference Include="Microsoft.Data.SqlClient" Version="6.0.1" />
Tested and worked perfectly