c# - name - xml doc
¿La mejor forma de invocar un código cruzado? (5)
Sé que esta pregunta ya se hizo antes, pero estoy buscando una forma de:
- optimizar la creación de código seguro de subprocesos cruzados.
- reutilice este código en cualquier situación (sin referencias a Windows Forms).
Esto es lo que tengo hasta ahora, pero quiero eliminar las referencias de Windows Forms. ¿Algunas ideas?
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 clase anterior se puede usar de esta manera:
SafeInvoke _safeInvoker = new SafeInvoke();
void SafeClearItems()
{
_safeInvoker.Invoke(delegate
{
listView1.Items.Clear();
});
}
¿Cómo eliminaría System.Windows.Forms.Control en la clase SafeInvoke pero mantendría la misma funcionalidad?
Aquí está en VB.net, muy similar a la respuesta de Samuel. Tengo cuatro sobrecargas dependiendo de si quiere una subrutina o función y si hay o no un parámetro. Sería fácil agregar más sobrecargas para más parámetros. VB.Net es capaz de inferir los tipos.
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
Uso (ejecuta esto en 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
Hoy en día es fácil invocar, por ejemplo, decir que queremos invocar una etiqueta (lblVal) para obtener el valor de txtVal
lblVal.invoke((MethodInvoker)delegate{txtVal.Text = lblVal.Text;});
tan fácil como eso: D
También podría usar un método de extensión y lambdas para hacer su código mucho más limpio.
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);
}
}
}
Entonces ahora puede usar InvokeEx en cualquier ISynchronizeInvoke y poder acceder a las propiedades y campos de implementación de clase.
this.InvokeEx(f => f.listView1.Items.Clear());
Use ISynchronizeInvoke lugar de Control . Esa es la interfaz que Control implementa con Invoke/BeginInvoke/EndInvoke/InvokeRequired .
Una alternativa es usar SynchronizationContext.Current , que es lo que utiliza BackgroundWorker , creo.
aquí está el código equivalente de VB a la respuesta de Samuel que uso. note que en realidad tengo 2 funciones de extensiones, pero debo admitir que no sé por qué están ahí. Copié mi versión de C # hace años (tal vez de este sitio) y tenía ambas funciones de extensión, pero por qué razón, no entiendo completamente. Acabo de copiarlo y cómo usarlo, y medio entiendo todo lo que sucede bajo el capó con estas complicadas funciones.
#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
Y la versión C # es:
#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
Feliz codificación!