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存储带有参数的操作列表,然后执行它们

action .net c#

-1

tobeypeters · 技术社区 · 6 年前

我有一个操作枚举,我想运行:

public enum theActions
{
    action1,
    action2
}

我想把它们储存在字典里:

public Dictionary<theActions, Action> _theActions { get; }

_theActions = new Dictionary<theActions, Action>
{
    [theActions.action1] = () => action1Func()
};

每一个动作我都有自己的功能:

public void action1Func(int inParam)
{
    //do whatever
}

稍后,我需要调用其中一个函数:

public void execAction(int inVar, Action action) 
{ 
    //inVar isn't the parameter I want to pass to the action. It's used, for something else.
    action(); 
}

execAction(1, _theActions[theActions.action1]);

我不确定,如何更改代码以使操作在任何地方都采用参数,如果我需要一个不需要参数的操作呢?我需要在那个函数中添加一个伪参数吗?

到目前为止,我明白了:

using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public enum theActions
        {
            action1,
            action2
        }

        public Dictionary<theActions, Action<int>> _theActions { get; }

        public void execAction(int inVar, Action<int> action)
        {
            //inVar isn't the parameter I want to pass to the action. It's used, for something else.
//            action();
        }

        public Form1()
        {
            InitializeComponent();

            _theActions = new Dictionary<theActions, Action<int>>
            {
                [theActions.action1] = (Action<int>)((int x) => action1Func(x))
            };

        }

        public void action1Func(int inParam)
        {
            //do whatever
            MessageBox.Show($"Hello ... inParam : {inParam}");
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //This works manually
            _theActions[theActions.action1].Invoke(12);

            //But, I want the execAction to work
            //execAction(1, _theActions[theActions.action1]);
        }
    }
}

它可以手动调用它。我只需要帮助进入execAction()并运行它。所以,关闭。

2 回复 | 直到 6 年前

nvoigt 6 年前

public void execAction(int someInt, Action action)
{
    action();

    // or: action.Invoke();
}

您应该能够在初始化中删除整个lambda,因为您已经有一个具有一个int参数的方法:

public Form1()
{
    InitializeComponent();

    _theActions = new Dictionary<theActions, Action<int>>
    {
        [theActions.action1] = action1Func
    };
}

带有特定参数的调用如下所示:

int yourParameter = 12345;
execAction(42, () => (_theActions[theActions.action1]).Invoke(yourParameter));

Cosmin Sontu 6 年前

试着放下字典,改用这个:

public void action1Func(int p1) //action 1 has one int parameter
{
}
public void action2Func() //let's consider action 2 takes no parameters
{
}
public void action3Func(int p1, int p2, int p3)
{
}
// Order of parameters was changed to leverage implicit null parameters for convenience
// See invocations below
public void execAction(theActions action, 
                       int? inVar1 = null, int? inVar2 = null, int? inVar3 = null) 
{
    switch (action) // Based on action kind, invoke the right function.
    {               // The mapping is now coded in a switch statement 
                    // instead of a Dictionary declaration
        case theActions.action1: action1Func(inVar1.Value); break;
        case theActions.action2: action2Func(); break;
        case theActions.action3: action3Func(inVar1.Value, inVar2.Value, inVar3.Value); break;
    }
}
// Invocations
execAction(theActions.action1, 1);
execAction(theActions.action2);
execAction(theActions.action3, 1, 3, 5);

如果对执行执行正确使用隐式参数声明,则可以调用具有任意数量参数的方法。

您可以执行参数验证(例如,在调用之前,您可以检查IvAR1.HasValue=真)。否则,如果省略了参数(NulabLe.Valp抛出无效操作异常,如果HasValue为false),代码将很快失败。

如果多个参数增长并变得不可管理,则可以将它们放入参数包类中,并通过构造函数验证它们的初始化。

如果定义了这些重载,则可以获得更多的安全性(编译时检查):

public void execAction1(int p1)
    => execAction(theActions.action1, p1);
public void execAction2()
    => execAction(theActions.action2);
public void execAction3(int p1, int p2, int p3)
    => execAction(theActions.action3, p1, p2, p3);

// Invocations will be
execAction1(1);
execAction2();
execAction3(1, 3, 5);

但这最后一步有点违背了目的。您可以调用原来的方法。