CODEWITHSUNDEEP
c#linqexpression-treesdynamic-language-runtime
Jason Baker
Jason Baker

Reputation: 198577

How do I make a LINQ expression to call a method?

I've been playing around with the DLR a bit and am a bit stuck on calling methods. For example, suppose I want to make an expression to push something onto a stack:

class StackInfo{

    protected Stack<SomeClass> _stack;

    public Expression Push(SomeClass item)
    {
        MethodInfo mi = _stack.GetType().GetMethod("Push");
        return Expression.Call(_stack, mi, item);
    }
}

I'm getting stuck because I'm not really sure how to get an Expression out of _stack or item. Could somebody push me in the right direction?

Upvotes: 2

Views: 2668

Answers (1)

Bryan Watts
Bryan Watts

Reputation: 45445

Use the Expression.Constant factory method:

class StackInfo
{
    protected Stack<SomeClass> _stack;

    public Expression Push(SomeClass item)
    {
        MethodInfo mi = _stack.GetType().GetMethod("Push");

        return Expression.Call(Expression.Constant(_stack), mi, Expression.Constant(item));
    }
}

Upvotes: 3

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