Menu
static void Main()
{
Action<string> myAction = SomeMethod;
myAction("Hello World");
myAction.Invoke("Hello World");
}
static void SomeMethod(string someString)
{
Console.WriteLine(someString);
}
The output for the above is:
Hello World
Hello World
Now my question(s) is
What is the difference between the two ways to call the Action, if any?
Is one better than the other?
When use which?
Thanks
333
Action is a delegate type defined in the System namespace. An Action type delegate is the same as Func delegate except that the Action delegate doesn't return a value. In other words, an Action delegate can be used with a method that has a void return type. For example, the following delegate prints an int value.
LINQ in Action is a fast-paced, comprehensive tutorial for professional developers who want to use LINQ. This book explores what can be done with LINQ, shows you how it works in an application, and addresses the emerging best practices.
You can use the Action<T> delegate to pass a method as a parameter without explicitly declaring a custom delegate. The encapsulated method must correspond to the method signature that is defined by this delegate.
All delegate types have a compiler-generated Invoke method.
C# allows you to call the delegate itself as a shortcut to calling this method.
They both compile to the same IL:
Action<string> x = Console.WriteLine;
x("1");
x.Invoke("2");
IL_0000: ldnull
IL_0001: ldftn System.Console.WriteLine
IL_0007: newobj System.Action<System.String>..ctor
IL_000C: stloc.0
IL_000D: ldloc.0
IL_000E: ldstr "1"
IL_0013: callvirt System.Action<System.String>.Invoke
IL_0018: ldloc.0
IL_0019: ldstr "2"
IL_001E: callvirt System.Action<System.String>.Invoke
(The ldnull is for the target parameter in an open delegate)
130
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
