private void SetAmbientScope(DbContextScope newAmbientScope)
{
if (newAmbientScope == null)
{
throw new ArgumentNullException("newAmbientScope");
}
var current = CallContext.LogicalGetData(AmbientDbContextScopeKey) as InstanceIdentifier;
if (current == newAmbientScope.instanceIdentifier)
{
return;
}
// Store the new scope's instance identifier in the CallContext, making it the ambient scope
CallContext.LogicalSetData(AmbientDbContextScopeKey, newAmbientScope.instanceIdentifier);
// Keep track of this instance (or do nothing if we're already tracking it)
DbContextScopeInstances.GetValue(newAmbientScope.instanceIdentifier, key => newAmbientScope);
}
/// <summary>
/// Initializes a new instance of the <see cref="DbContextScope" /> class.
/// </summary>
/// <param name="purpose">Will this dbcontext scope be used for reading or writing?</param>
/// <param name="isNewScope">Will this dbcontext scope be a new DbContextScope.</param>
public DbContextScope(DbContextScopePurpose purpose, bool isNewScope = false)
{
this.purpose = purpose;
this.parentScope = GetAmbientScope();
if (this.parentScope != null && !isNewScope)
{
this.scopedDbContexts = this.parentScope.DbContext;
}
else
{
this.scopedDbContexts = new DbContextCollection(purpose == DbContextScopePurpose.Writing);
this.isRoot = true;
}
this.SetAmbientScope(this);
if (purpose == DbContextScopePurpose.Writing && !this.scopedDbContexts.ForWriting)
{
throw new InvalidOperationException(
"Can't open a child DbContextScope for writing when the root scope " +
"is opened for reading.");
}
}
public TDbContext Get <TDbContext>() where TDbContext : DbContext
{
var ambientScope = DbContextScope.GetAmbientScope();
return(ambientScope == null ? null : ambientScope.DbContext.Get <TDbContext>());
}