La meilleure façon de Invoke tout code foirés?

Question

Je sais que cette question a été posée, mais je suis à la recherche d'un moyen de:

1. simplifier la création de code-thread croix sécurité.
2. réutiliser ce code dans toute situation (pas de références Windows Forms).

Voici ce que j'ai jusqu'à présent, mais je veux supprimer les références Windows Forms. Toutes les idées?

public delegate void SafeInvokeDelegate(System.Action action);
public class SafeInvoke
{
    private readonly System.Windows.Forms.Control _threadControl;

    public SafeInvoke()
    {
        _threadControl = new System.Windows.Forms.Control();
    }

    public void Invoke(System.Action action)
    {
        if (_threadControl.InvokeRequired)
            _threadControl.Invoke(new SafeInvokeDelegate(Invoke), new object[] {action});
        else if (action != null) action();
    }
}

La classe ci-dessus peut être utilisé de cette façon:

SafeInvoke _safeInvoker = new SafeInvoke();
void SafeClearItems()
{
    _safeInvoker.Invoke(delegate
        {
            listView1.Items.Clear();
        });
}

Comment puis-je supprimer le System.Windows.Forms.Control dans la classe SafeInvoke mais garder les mêmes fonctionnalités?

Answer 1

Vous pourriez également utiliser une méthode d'extension et lambdas pour rendre votre code beaucoup plus propre.

using System.ComponentModel;
public static class ISynchronizeInvokeExtensions
{
  public static void InvokeEx<T>(this T @this, Action<T> action) where T : ISynchronizeInvoke
  {
    if (@this.InvokeRequired)
    {
      @this.Invoke(action, new object[] { @this });
    }
    else
    {
      action(@this);
    }
  }
}

Alors maintenant, vous pouvez utiliser InvokeEx sur tout ISynchronizeInvoke et être en mesure d'accéder aux propriétés et domaines de la mise en œuvre de la classe.

this.InvokeEx(f => f.listView1.Items.Clear());

Answer 2

ISynchronizeInvoke au lieu de Control. C'est l'interface qui Control met en œuvre avec Invoke/BeginInvoke/EndInvoke/InvokeRequired.

Une autre solution consiste à utiliser SynchronizationContext.Current -. ce qui est ce que BackgroundWorker utilisations, je crois

Answer 3

Aujourd'hui, il est facile de Invoke.
par exemple. Disons que nous voulons invoquer une étiquette (lblVal) pour obtenir la valeur de txtVal

lblVal.Invoke((MethodInvoker)delegate{lblVal.Text = txtVal.Text;});

... il est aussi simple que cela: D

Answer 4

Ici, il est en VB.net, très semblable à la réponse de Samuel. J'ai quatre selon que les surcharges que vous voulez un sous-programme ou la fonction et si oui ou non il y a un paramètre. Il serait facile d'ajouter plus pour plus de paramètres surcharges. VB.Net est en mesure de déduire les types.

Module ISynchronizeInvokeExtensions
    Public Delegate Function GenericLambdaFunctionWithParam(Of InputType, OutputType)(ByVal input As InputType) As OutputType
    Private Delegate Function InvokeLambdaFunctionCallback(Of InputType, OutputType)(ByVal f As GenericLambdaFunctionWithParam(Of InputType, OutputType), ByVal input As InputType, ByVal c As System.ComponentModel.ISynchronizeInvoke) As OutputType
    Public Function InvokeEx(Of InputType, OutputType)(ByVal f As GenericLambdaFunctionWithParam(Of InputType, OutputType), ByVal input As InputType, ByVal c As System.ComponentModel.ISynchronizeInvoke) As OutputType
        If c.InvokeRequired Then
            Dim d As New InvokeLambdaFunctionCallback(Of InputType, OutputType)(AddressOf InvokeEx)
            Return DirectCast(c.Invoke(d, New Object() {f, input, c}), OutputType)
        Else
            Return f(input)
        End If
    End Function

    Public Delegate Sub GenericLambdaSubWithParam(Of InputType)(ByVal input As InputType)
    Public Sub InvokeEx(Of InputType)(ByVal s As GenericLambdaSubWithParam(Of InputType), ByVal input As InputType, ByVal c As System.ComponentModel.ISynchronizeInvoke)
        InvokeEx(Of InputType, Object)(Function(i As InputType) As Object
                                           s(i)
                                           Return Nothing
                                       End Function, input, c)
    End Sub

    Public Delegate Sub GenericLambdaSub()
    Public Sub InvokeEx(ByVal s As GenericLambdaSub, ByVal c As System.ComponentModel.ISynchronizeInvoke)
        InvokeEx(Of Object, Object)(Function(i As Object) As Object
                                        s()
                                        Return Nothing
                                    End Function, Nothing, c)
    End Sub

    Public Delegate Function GenericLambdaFunction(Of OutputType)() As OutputType
    Public Function InvokeEx(Of OutputType)(ByVal f As GenericLambdaFunction(Of OutputType), ByVal c As System.ComponentModel.ISynchronizeInvoke) As OutputType
        Return InvokeEx(Of Object, OutputType)(Function(i As Object) f(), Nothing, c)
    End Function
End Module

Utilisation (exécuter ce dans un BackgroundWorker):

    InvokeEx(Sub(x As String) Me.Text = x, "foo", Me) 'set form title to foo
    InvokeEx(AddressOf MsgBox, Me.Text, Me)
    InvokeEx(Sub() Me.Text &= "!", "foo", Me) 'append "!" to form title
    InvokeEx(AddressOf MsgBox, Me.Text, Me)
    Dim s As String = InvokeEx(Function() Me.Text, Me) & "bar" 'get form title to backgorundworker thread
    InvokeEx(AddressOf MsgBox, s, Me) 'display the string from backgroundworker thread

Answer 5

Voici le code équivalent VB à la réponse de Samuel que je l'utilise. Remarquez que j'ai fait 2 fonctions extensions, mais je dois admettre que je ne sais pas pourquoi ils sont là. i copié mon C # il y a quelques années de version (peut-être de ce site) et il y avait deux fonctions d'extension, mais pour quelle raison, je ne comprends pas bien. Je viens de copier et comment l'utiliser, et je comprends la moitié tout ce qui se passe « sous le capot » avec ces fonctions complexes.

#Const System_ComponentModel = True
#Const System_Drawing = False

Option Compare Binary
Option Explicit On
Option Strict On

Imports System.Collections
Imports System.Runtime.CompilerServices ' for Extension() attribute
Imports System.Text
#If System_ComponentModel Then
Imports System.ComponentModel
#End If
#If System_Drawing Then
Imports System.Drawing
#End If

Public Module MyExtensions

    ' other #Region blocks are removed. i use many in my Extensions
    ' module/class. the below code is only the 2 relevant extension
    ' for this 'SafeInvoke' functionality. but i use other regions
    ' such as "String extensions" and "Numeric extensions". i use
    ' the above System_ComponentModel and System_Drawing compiler
    ' directives to include or exclude blocks of code that i want
    ' to either include or exclude in a project, which allows me to
    ' easily compare my code in one project with the same file in
    ' other projects to syncronise new changes across projects.
    ' you can scrap pretty much all the code above,
    ' but i'm giving it here so you see it in the full context.

    #Region "ISynchronizeInvoke extensions"

    #If System_ComponentModel Then

        <Extension()>
        Public Function SafeInvoke(Of T As ISynchronizeInvoke, TResult)(isi As T, callFunction As Func(Of T, TResult)) As TResult
            If (isi.InvokeRequired) Then
                Dim result As IAsyncResult = isi.BeginInvoke(callFunction, New Object() {isi})
                Dim endresult As Object = isi.EndInvoke(result)
                Return DirectCast(endresult, TResult)
            Else
                Return callFunction(isi)
            End If
        End Function

        ''' <summary>
        ''' This can be used in VB with:
        ''' txtMyTextBox.SafeInvoke(Sub(d) d.Text = "This is my new Text value.")
        ''' or:
        ''' txtMyTextBox.SafeInvoke(Sub(d) d.Text = myTextStringVariable)
        ''' </summary>
        ''' <typeparam name="T"></typeparam>
        ''' <param name="isi"></param>
        ''' <param name="callFunction"></param>
        ''' <remarks></remarks>
        <Extension()>
        Public Sub SafeInvoke(Of T As ISynchronizeInvoke)(isi As T, callFunction As Action(Of T))
            If isi.InvokeRequired Then
                isi.BeginInvoke(callFunction, New Object() {isi})
            Else
                callFunction(isi)
            End If
        End Sub

    #End If

    #End Region

    ' other #Region blocks are removed from here too.

End Module

Et la version C # est:

#define System_ComponentModel
#undef  System_Drawing

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

#if System_ComponentModel
using System.ComponentModel;
#endif
#if System_Drawing
using System.Drawing;
#endif

namespace MyCompany.Extensions
{
    static partial class MyExtensions
    {

        // other #Region blocks are removed. i use many in my Extensions
        // module/class. the below code is only the 2 relevant extension
        // for this 'SafeInvoke' functionality. but i use other regions
        // such as "String extensions" and "Numeric extensions". i use
        // the above System_ComponentModel and System_Drawing compiler
        // directives to include or exclude blocks of code that i want
        // to either include or exclude in a project, which allows me to
        // easily compare my code in one project with the same file in
        // other projects to syncronise new changes across projects.
        // you can scrap pretty much all the code above,
        // but i'm giving it here so you see it in the full context.

        #region ISynchronizeInvoke extensions
#if System_ComponentModel

        public static TResult SafeInvoke<T, TResult>(this T isi, Func<T, TResult> callFunction) where T : ISynchronizeInvoke
        {
            if (isi.InvokeRequired)
            {
                IAsyncResult result = isi.BeginInvoke(callFunction, new object[] { isi });
                object endResult = isi.EndInvoke(result); return (TResult)endResult;
            }
            else
                return callFunction(isi);
        }

        /// <summary>
        /// This can be used in C# with:
        /// txtMyTextBox.SafeInvoke(d => d.Text = "This is my new Text value.");
        /// or:
        /// txtMyTextBox.SafeInvoke(d => d.Text = myTextStringVariable);
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="isi"></param>
        /// <param name="callFunction"></param>
        public static void SafeInvoke<T>(this T isi, Action<T> callFunction) where T : ISynchronizeInvoke
        {
            if (isi.InvokeRequired) isi.BeginInvoke(callFunction, new object[] { isi });
            else
                callFunction(isi);
        }

#endif
        #endregion

        // other #Region blocks are removed from here too.

    } // static class MyExtensions

} // namespace

Bonne programmation!