You can build an expression tree which contains a try-finally blocks by using Expression.TryFinally method. It creates a TryExpression representing a try block with a finally block and no catch statements.
For example, you have the following code.
try
{
Console.WriteLine("Try block");
}
finally
{
Console.WriteLine("Finally block");
}
Here is the code that is required to build the same functionality using expression tree.
var tryBlock = WriteLineExpression("Try block");
var finallyBlock = WriteLineExpression("Finally block");
TryExpression tryFinallyExpr = Expression.TryFinally(tryBlock, finallyBlock);
Expression.Lambda<Action>(tryFinallyExpr).Compile()();
This example shows how to create an expression that contains a goto statement. Here is the code for WriteLineExpression method
public static Expression WriteLineExpression(string s)
{
return Expression.Call(null,
typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
Expression.Constant(s));
}