dotnet/Documentation/compatibility/targetframeworkname-for-default-app-domain-no-longer-defaults-to-null-if-not-set.md

TargetFrameworkName for default app domain no longer defaults to null if not set

Scope

Edge

Version Introduced

4.6

Source Analyzer Status

Planned

Change Description

The xref:System.AppDomainSetup.TargetFrameworkName?displayProperty=name was previously null in the default app domain, unless it was explicitly set. Beginning in 4.6, the xref:System.AppDomainSetup.TargetFrameworkName?displayProperty=name property for the default app domain will have a default value derived from the TargetFrameworkAttribute (if one is present). Non-default app domains will continue to inherit their xref:System.AppDomainSetup.TargetFrameworkName?displayProperty=name from the default app domain (which will not default to null in 4.6) unless it is explicitly overridden.

• Quirked
• Build-time break

Recommended Action

Code should be updated to not depend on xref:System.AppDomainSetup.TargetFrameworkName defaulting to null. If it is required that this property continue to evaluate to null, it can be explicitly set to that value.

Affected APIs

• M:System.AppDomainSetup.get_TargetFrameworkName

Category

Core