I'm trying to get the following simple Delegate example working. According to a book I've taken it from it should be ok, but I get a Method name expected
error.
namespace TestConsoleApp
{
class Program
{
private delegate string D();
static v开发者_如何转开发oid Main(string[] args)
{
int x = 1;
D code = new D(x.ToString());
}
}
}
Any help?
Remove the ():
D code = new D(x.ToString);
You want to specify the method, not execute it.
I think you mean:
D code = new D(x.ToString);
Note the lack of brackets. With the brackets on, it was a method invocation - i.e. you were trying to execute x.ToString()
in that line of code. Without the brackets, it's a method group - an expression which tells the compiler to look at the available methods with that name (in that context), precisely for the purpose of creating delegates.
Which book are you using? If it really has the brackets in the examples it shows, you may want to email the author (or at least check the book's errata page). If it's C# in Depth, I'll go and cry in a corner...
You need to feed a method into the delegate constructor.
x.ToString()
is not a method, but a string. Use
D code = new D(x.ToString);
Try taking the brackets off the end of the method, you are passing the method, hence don't need to use the brackets.
D code = new D(x.ToString); // Note the: ()
You need to pas the method to be executed in the delegate. What that you're doing is passing the value instead of the signature of the function.
Should be:
D code = new D(x.ToString);
精彩评论