Information Technology Reference
In-Depth Information
where
(destProp !=
null
) &&
(destProp.CanWrite)
select
Expression
.Assign(
Expression
.Property(dest,
destProp),
Expression
.Property(source,
srcProp));
// put together the body:
var
body =
new
List
<
Expression
>();
body.Add(
Expression
.Assign(dest,
Expression
.New(
typeof
(TDest))));
body.AddRange(assignments);
body.Add(dest);
var
expr =
Expression
.Lambda<
Func
<TSource, TDest>>(
Expression
.Block(
new
[] { dest },
// expression parameters
body.ToArray()
// body
),
source
// lambda expression
);
var
func = expr.Compile();
converter = func;
}
}
This method creates code that mimics the pseudo code shown before. First,
you declare the parameter:
var
source =
Expression
.Parameter(
typeof
(TSource),
"source"
);
Then, you have to declare a local variable to hold the destination:
var
dest =
Expression
.Variable(
typeof
(TDest),
"dest"
);
The bulk of the method is the code that assigns properties from the source
object to the destination object. I wrote this code as a LINQ query. The
source sequence of the LINQ query is the set of all public instance prop-
erties in the source object where there is a
get
accessor:
