Question

Possible Duplicate:
Combining two expressions (Expression<Func<T, bool>>)

I have a method taking in a single Expression<Func<bool>> parameter

void MethodOne(Expression<Func<bool>> expression)

I’ve got multiple instances of Expression<Func<bool>>. How do I dynamically combine these expressions into a single Expression<Func<bool>> using Expression.OrElse (i.e. building up an expression tree)?

For example if I have two expressions such as

() => objectA.PropertyOneIsSet

and

() => objectB.PropertyTwoIsSet

I want the end result to be:

() => objectA.PropertyOneIsSet || objectB.PropertyTwoIsSet

so I can pass this to my method above.

Answer 1

You can create ExpressionVisitor to combine queries. Check this msdn blog for more info: Combining Predicates (Answer 3). He talking about EF, but you can use it in your case