帮助修复 C# 中的错误“引用或输出参数必须是可赋值的"； [英] Help fixing errors in C# "A ref or out argument must be an assignable"

问题描述

这是我遇到错误的一段代码:

Here's a block of code I'm having errors with:

    public static bool Flash(Form form)
    {
        return (Win2000OrLater && FlashWindowEx(ref Create_FLASHWINFO(form.Handle, 15, uint.MaxValue, 0))); //A ref or out argument must be an assignable variable

    }

    public static bool Flash(Form form, uint count)
    {
        return (Win2000OrLater && FlashWindowEx(ref Create_FLASHWINFO(form.Handle, 3, count, 0))); //A ref or out argument must be an assignable variable
    }
    private static extern bool FlashWindowEx(ref FLASHWINFO pwfi);
    public static bool Start(Form form)
    {
        return (Win2000OrLater && FlashWindowEx(ref Create_FLASHWINFO(form.Handle, 3, uint.MaxValue, 0))); //A ref or out argument must be an assignable variable
    }

    public static bool Stop(Form form)
    {
        return (Win2000OrLater && FlashWindowEx(ref Create_FLASHWINFO(form.Handle, 0, uint.MaxValue, 0))); //A ref or out argument must be an assignable variable
    }

    private static bool Win2000OrLater
    {
        get
        {
            return (Environment.OSVersion.Version.Major >= 5);
        }
    }

错误信息是:

ref 或 out 参数必须是可赋值的

A ref or out argument must be an assignable

推荐答案

关于你的第一个错误，你需要将 FlashWindow 作为变量引入，例如

Regarding your first errors, you need to introduct the FlashWindow as a variable so for example

这个:

public static bool Flash(Form form)
{
    return (Win2000OrLater && FlashWindowEx(ref Create_FLASHWINFO(form.Handle, 15, uint.MaxValue, 0))); //A ref or out argument must be an assignable variable
}

变成:

public static bool Flash(Form form)
{
    if (Win2000OrLater)
    {
        FLASHWINFO fi = Create_FLASHWINFO(form.Handle, 15, uint.MaxValue, 0);
        return (FlashWindowEx(ref fi));
    }
    return false;
}

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