In .NET Core and .NET Framework ≥4.0 there is a generic parse method:
Enum.TryParse("Active", out StatusEnum myStatus);
This also includes C#7's new inline out
variables, so this does the try-parse, conversion to the explicit enum type and initialises+populates the myStatus
variable.
If you have access to C#7 and the latest .NET this is the best way.
Original Answer
In .NET it's rather ugly (until 4 or above):
StatusEnum MyStatus = (StatusEnum) Enum.Parse(typeof(StatusEnum), "Active", true);
I tend to simplify this with:
public static T ParseEnum<T>(string value)
{
return (T) Enum.Parse(typeof(T), value, true);
}
Then I can do:
StatusEnum MyStatus = EnumUtil.ParseEnum<StatusEnum>("Active");
One option suggested in the comments is to add an extension, which is simple enough:
public static T ToEnum<T>(this string value)
{
return (T) Enum.Parse(typeof(T), value, true);
}
StatusEnum MyStatus = "Active".ToEnum<StatusEnum>();
Finally, you may want to have a default enum to use if the string cannot be parsed:
public static T ToEnum<T>(this string value, T defaultValue)
{
if (string.IsNullOrEmpty(value))
{
return defaultValue;
}
T result;
return Enum.TryParse<T>(value, true, out result) ? result : defaultValue;
}
Which makes this the call:
StatusEnum MyStatus = "Active".ToEnum(StatusEnum.None);
However, I would be careful adding an extension method like this to string
as (without namespace control) it will appear on all instances of string
whether they hold an enum or not (so 1234.ToString().ToEnum(StatusEnum.None)
would be valid but nonsensical) . It's often be best to avoid cluttering Microsoft's core classes with extra methods that only apply in very specific contexts unless your entire development team has a very good understanding of what those extensions do.
As per the documentation: FROM (Transact-SQL):
<join_type> ::=
[ { INNER | { { LEFT | RIGHT | FULL } [ OUTER ] } } [ <join_hint> ] ]
JOIN
The keyword OUTER
is marked as optional (enclosed in square brackets). In this specific case, whether you specify OUTER
or not makes no difference. Note that while the other elements of the join clause is also marked as optional, leaving them out will make a difference.
For instance, the entire type-part of the JOIN
clause is optional, in which case the default is INNER
if you just specify JOIN
. In other words, this is legal:
SELECT *
FROM A JOIN B ON A.X = B.Y
Here's a list of equivalent syntaxes:
A LEFT JOIN B A LEFT OUTER JOIN B
A RIGHT JOIN B A RIGHT OUTER JOIN B
A FULL JOIN B A FULL OUTER JOIN B
A INNER JOIN B A JOIN B
Also take a look at the answer I left on this other SO question: SQL left join vs multiple tables on FROM line?.
Best Answer
Anybody who tells you to use .DefaultIfEmpty() as part of an outer join in LINQ to Entities hasn't actually tried it themselves! Tt simply does not work - at least as at .NET 3.5 SP1.
This blogger tells you how you should actually do it. Essentially, .NET does outer joins in LINQ to Entities by default, so you should leave out the .DefaultIfEmpty(). For multiple outer joins you have to nest the query groups to keep their context clear.