不能使用可变参数函数作为 Action 的参数 C# [英] Can't use variadic-function as Action's parameter C#

问题描述

需要找到一种方法将带有可变数量参数的委托Action(参见下面的MyLog)传递给另一个方法(参见ExtractToDirectory 低于 MyLog).

Need to find a way to pass a delegate Action with a variable number of parameters (see MyLog below) to another method (see ExtractToDirectory below MyLog).

我有一个日志方法:

public static void MyLog(string variable, params object[] args)
{
  textBoxLog.AppendText(string.Format(message, args) + Environment.NewLine);
}

在同一个 WinForm 类中进一步调用:

And a call further in the same WinForm class:

private void buttonInstall_Click(object sender, EventArgs e)
{
  using (Stream zipStream = <Get stream from Resources>)
  using (ZipArchive zip = new ZipArchive(zipStream))
    zip.ExtractToDirectory(@"Z:\", MyLog);
}

带有方法的静态类:

public static class ZipFileExtensions
{
  public static void ExtractToDirectory(this ZipArchive source, string destinationDirectoryName, Action<string, params object[]> myLog)
  {
    myLog("Starting {0} extraction", source.Name);
  }
}

问题在于ExtractToDirectory 的声明.params 关键字带有下划线并带有错误:Type expected.

The problem is with the declaration of ExtractToDirectory. The params keyword gets underlined with error : Type expected.

我尝试不输入参数，但是 VS 需要一个对象数组而不是我需要的可变长度参数.

I tried not to put params, but then VS expects an object array instead of variable length parameters as I need.

有什么线索吗?

推荐答案

Following quetzalcoatl answer，我最终得到了这个:

Following quetzalcoatl answer, I ended up with this:

public partial class MainForm : Form
{
  public delegate void LogAction(string message, params object[] args);
  public void Logger(string message, params object[] args)
  {
    if (args != null)
      textBoxLog.AppendText(string.Format(message, args) + Environment.NewLine);
    else
      textBoxLog.AppendText(message + Environment.NewLine);
    Application.DoEvents();
  }

  private void buttonInstall_Click(object sender, EventArgs e)
  {
    Logger("Button clicked");
    using (Stream zipStream = Assembly.GetExecutingAssembly().GetManifestResourceStream(MethodBase.GetCurrentMethod().DeclaringType.Namespace + ".Resources.test.zip"))
    using (ZipArchive zip = new ZipArchive(zipStream))
      zip.ExtractToDirectory(Program.DestinationInstallation, Logger);
}

<小时>

public static class ZipFileExtensions
{
  public static void ExtractToDirectory(this ZipArchive source, string destinationDirectoryName, MainForm.LogAction myLogger)
  {
    int number = 20180803;
    myLogger("{0} >> {1} (ok)", DateTime.Now, number);
  }
}

<小时>

非常感谢帮助.

---

Help was much appreciated.

这篇关于不能使用可变参数函数作为 Action 的参数 C#的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！