Delegate.GetInvocationList 方法
定義
重要
部分資訊涉及發行前產品,在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊,不做任何明確或隱含的瑕疵擔保。
傳回委派的引動過程清單。
public:
virtual cli::array <Delegate ^> ^ GetInvocationList();
public virtual Delegate[] GetInvocationList ();
abstract member GetInvocationList : unit -> Delegate[]
override this.GetInvocationList : unit -> Delegate[]
Public Overridable Function GetInvocationList () As Delegate()
傳回
Delegate[]
委派的陣列,表示目前委派的引動過程清單。
範例
下列範例會將三種方法指派給委派。 然後它會呼叫 GetInvocationList 方法,以取得指派給委派的方法總數、以反向循序執行委派,以及執行名稱不包含子字串 「File」 的方法。
using System;
using System.IO;
using System.Reflection;
using System.Windows.Forms;
public class Example
{
public static void Main()
{
Action<String> outputMessage = null;
outputMessage += Console.WriteLine;
outputMessage += OutputToFile;
outputMessage += ShowMessageBox;
// Dim output1 As Action(Of String) = AddressOf Console.WriteLine
// Dim output2 As Action(Of String) = AddressOf OutputToFile
// Dim output3 As Action(Of String) = AddressOf MessageBox.Show
//
// outputMessage = [Delegate].Combine( { output1, output2, output3 } )
Console.WriteLine("Invocation list has {0} methods.",
outputMessage.GetInvocationList().Length);
// Invoke delegates normally.
outputMessage("Hello there!");
Console.WriteLine("Press <Enter> to continue...");
Console.ReadLine();
// Invoke each delegate in the invocation list in reverse order.
for (int ctr = outputMessage.GetInvocationList().Length - 1; ctr >= 0; ctr--) {
var outputMsg = outputMessage.GetInvocationList()[ctr];
outputMsg.DynamicInvoke("Greetings and salutations!");
}
Console.WriteLine("Press <Enter> to continue...");
Console.ReadLine();
// Invoke each delegate that doesn't write to a file.
for (int ctr = 0; ctr < outputMessage.GetInvocationList().Length; ctr++) {
var outputMsg = outputMessage.GetInvocationList()[ctr];
if (! outputMsg.GetMethodInfo().Name.Contains("File"))
outputMsg.DynamicInvoke( new String[] { "Hi!" } );
}
}
private static void OutputToFile(String s)
{
var sw = new StreamWriter(@".\output.txt");
sw.WriteLine(s);
sw.Close();
}
private static void ShowMessageBox(String s)
{
MessageBox.Show(s);
}
}
open System
open System.IO
open System.Reflection
open System.Windows.Forms
let outputToFile (s: string) =
use sw = new StreamWriter(@".\output.txt")
sw.WriteLine s
let showMessageBox s =
MessageBox.Show s |> ignore
let outputMessage =
Delegate.Combine(
Action<string>(Console.WriteLine),
Action<string>(outputToFile),
Action<string>(showMessageBox))
:?> Action<string>
printfn $"Invocation list has {outputMessage.GetInvocationList().Length} methods."
// Invoke delegates normally.
outputMessage.Invoke "Hello there!"
printfn "Press <Enter> to continue..."
stdin.ReadLine() |> ignore
// Invoke each delegate in the invocation list in reverse order.
for i = outputMessage.GetInvocationList().Length - 1 downto 0 do
let outputMsg = outputMessage.GetInvocationList()[i]
outputMsg.DynamicInvoke "Greetings and salutations!"
|> ignore
printfn "Press <Enter> to continue..."
stdin.ReadLine() |> ignore
// Invoke each delegate that doesn't write to a file.
for i = 0 to outputMessage.GetInvocationList().Length - 1 do
let outputMsg = outputMessage.GetInvocationList()[i]
if not (outputMsg.GetMethodInfo().Name.Contains "File") then
outputMsg.DynamicInvoke "Hi!"
|> ignore
Imports System.IO
Imports System.Reflection
Imports System.Windows.Forms
Module Example
Public outputMessage As Action(Of String)
Public Sub Main()
Dim output1 As Action(Of String) = AddressOf Console.WriteLine
Dim output2 As Action(Of String) = AddressOf OutputToFile
Dim output3 As Action(Of String) = AddressOf MessageBox.Show
outputMessage = [Delegate].Combine( { output1, output2, output3 } )
Console.WriteLine("Invocation list has {0} methods.",
outputMessage.GetInvocationList().Count)
' Invoke delegates normally.
outputMessage("Hello there!")
Console.WriteLine("Press <Enter> to continue...")
Console.ReadLine()
' Invoke each delegate in the invocation list in reverse order.
For ctr As Integer = outputMessage.GetInvocationList().Count - 1 To 0 Step -1
Dim outputMsg = outputMessage.GetInvocationList(ctr)
outputMsg.DynamicInvoke("Greetings and salutations!")
Next
Console.WriteLine("Press <Enter> to continue...")
Console.ReadLine()
' Invoke each delegate that doesn't write to a file.
For ctr As Integer = 0 To outputMessage.GetInvocationList().Count - 1
Dim outputMsg = outputMessage.GetInvocationList(ctr)
If Not outputMsg.GetMethodInfo().Name.Contains("File") Then
outputMsg.DynamicInvoke( { "Hi!" } )
End If
Next
End Sub
Private Sub OutputToFile(s As String)
Dim sw As New StreamWriter(".\output.txt")
sw.WriteLine(s)
sw.Close()
End Sub
End Module
備註
陣列中的每個委派都只代表一個方法。
陣列中委派的順序與目前委派叫用這些委派所代表的方法的順序相同。