c#将参数传递给Action答案

【问题标题】：c# pass parameter to Actionc#将参数传递给Action
【发布时间】：2013-10-04 02:51:59
【问题描述】：

我有以下代码：

public partial class WaitScreen : Form
{
    public Action Worker { get; set; }

    public WaitScreen(Action worker)
    {
        InitializeComponent();

        if (worker == null)
            throw new ArgumentNullException();

        Worker = worker;
    }

    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);

        Task.Factory.StartNew(Worker).ContinueWith(t => { this.Close(); }, TaskScheduler.FromCurrentSynchronizationContext());
    }
}

这是消费者中的代码：

private void someButton_Click(object sender, EventArgs e)
{
    using (var waitScreen = new WaitScreen(SomeWorker))
        waitScreen.ShowDialog(this);
}

private void SomeWorker()
{
    // Load stuff from the database and store it in local variables.
    // Remember, this is running on a background thread and not the UI thread, don't touch controls.
}

现在，我必须在 Action "SomeWorker" 中添加一个参数，例如：

private void SomeWorker(Guid uid, String text)
    {
        // here will execute the task!!
    }

如何将参数 uid 和 text 传递给 Action？

是否可以使其通用，以便我可以传递任何参数，以便它可以处理任何数量和类型的参数？

感谢任何帮助！

【问题讨论】：

标签： c# multithreading winforms backgroundworker

【解决方案1】：

对于这种情况，我认为您不能使用Action<Guid, string>，因为我看不到您如何将参数传递给新表单。您最好的选择是使用匿名委托来捕获您要传入的变量。您仍然可以将函数分开，但您需要匿名委托来进行捕获。

private void someButton_Click(object sender, EventArgs e)
{
    var uid = Guid.NewGuid();
    var text = someTextControl.Text;

    Action act = () => 
        {
            //The two values get captured here and get passed in when 
            //the function is called. Be sure not to modify uid or text later 
            //in the someButton_Click method as those changes will propagate.
            SomeWorker(uid, text)
        }
    using (var waitScreen = new WaitScreen(act))
        waitScreen.ShowDialog(this);
}

private void SomeWorker(Guid uid, String text)
{
    // Load stuff from the database and store it in local variables.
    // Remember, this is running on a background thread and not the UI thread, don't touch controls.
}

【讨论】：

【解决方案2】：

Action 定义为delegate void Action()。因此，您不能将变量传递给它。

你想要的是一个Action<T, T2>，它公开了两个要传入的参数。

示例用法..随意将其应用于您自己的需要：

Action<Guid, string> action = (guid, str) => {
    // guid is a Guid, str is a string.
};


// usage
action(Guid.NewGuid(), "Hello World!");

【讨论】：