C＃错误：不是所有的代码路径返回值 [英] C# error: not all code paths return a value

问题描述

我已经声明在另一个类中的方法，它有一个错误并不是所有的代码路径返回值

I have declared a method in another class and it has an error "not all code paths return a value"

我想它返回一个true或false值到主程序。

I would like it to return a true or false value to the main program.

但是，当我宣布我的方法，公共静态无效，另一个错误产生，返回关键字后面不得通过对象的表情。

But when I declare my method, public static void, another error produces, a return keyword must not be followed by an object expression.

public class FileSearch
{
    public static Boolean SearchFiles(string path1, string path2)
    {
        bool isIdentical = false;
        string content1 = null;
        string content2 = null;

        DirectoryInfo d1 = new DirectoryInfo(path1);
        DirectoryInfo d2 = new DirectoryInfo(path2);

        foreach (FileInfo f1 in d1.GetFiles("*.txt", SearchOption.AllDirectories))
        {
            foreach (FileInfo f2 in d2.GetFiles("*.txt", SearchOption.AllDirectories))
            {
                content1 = (File.ReadAllText(f1.DirectoryName + "\\" + f1));
                content2 = (File.ReadAllText(f2.DirectoryName + "\\" + f2));

                isIdentical = content1.Equals(content2, StringComparison.Ordinal);

                if (isIdentical == false)
                {
                    return false;
                }
                else
                {
                    return true;
                }
            }
        }
    }
}

推荐答案

您的方法 SearchFiles 只返回一个值，如果 isIdentical 是假。如果是真正，该方法不会返回

Your method SearchFiles only returns a value if isIdentical is false. If it's true, the method never returns.

要删除此错误，写的是这样的：

To remove this error, write something like this:

public static Boolean SearchFiles(string path1, string path2)
{
    // do some work to assign a value to isIdentical
    if (isIdentical == false)
    {
        return false;
    }
    else
    {
        return true;
    }
}

要你的第二个问题：如果你宣布你的方法公共静态无效你绝不能收益任意值。 无效意味着该方法不会给你任何东西。

To your second question: If you declare your method as public static void you must not return any value. void means that the method will not give you anything back.

您可能想看看这个： 方法（C＃编程指南）， 。特别是关于返回值的部分。

You might want to have a look at this: Methods (C# Programming Guide), especially the part about return values.

编辑：既然你有你的的if / else 在的foreach 循环，你需要的东西是这样的：

Since you have your if / else in a foreach loop, you need something like this:

public static Boolean SearchFiles(string path1, string path2)
{
    foreach(var item in collection)
    {
        // do some work to assign a value to isIdentical
        if (isIdentical == false)
        {
            return false;
        }
        else
        {
            return true;
        }
    }
    // in case the collection is empty, you need to return something
    return false;
}

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