How can I make this work with deep properties
- by Martin Robins
Given the following code...
class Program {
static void Main(string[] args) {
Foo foo = new Foo { Bar = new Bar { Name = "Martin" }, Name = "Martin" };
DoLambdaStuff(foo, f => f.Name);
DoLambdaStuff(foo, f => f.Bar.Name);
}
static void DoLambdaStuff<TObject, TValue>(TObject obj, Expression<Func<TObject, TValue>> expression) {
// Set up and test "getter"...
Func<TObject, TValue> getValue = expression.Compile();
TValue stuff = getValue(obj);
// Set up and test "setter"...
ParameterExpression objectParameterExpression = Expression.Parameter(typeof(TObject)), valueParameterExpression = Expression.Parameter(typeof(TValue));
Expression<Action<TObject, TValue>> setValueExpression = Expression.Lambda<Action<TObject, TValue>>(
Expression.Block(
Expression.Assign(Expression.Property(objectParameterExpression, ((MemberExpression)expression.Body).Member.Name), valueParameterExpression)
), objectParameterExpression, valueParameterExpression
);
Action<TObject, TValue> setValue = setValueExpression.Compile();
setValue(obj, stuff);
}
}
class Foo {
public Bar Bar { get; set; }
public string Name { get; set; }
}
class Bar {
public string Name { get; set; }
}
The call to DoLambdaStuff(foo, f => f.Name) works ok because I am accessing a shallow property, however the call to DoLambdaStuff(foo, f => f.Bar.Name) fails - although the creation of the getValue function works fine, the creation of the setValueExpression fails because I am attempting to access a deep property of the object.
Can anybody please help me to modify this so that I can create the setValueExpression for deep properties as well as shallow?
Thanks.
