输出参数的重要性 [英] significance of out parameter

问题描述

大家好...
谁能解释我，为什么和在哪里使用"out"关键字及其含义.预先感谢

hi everyone...
Can anyone please explain me , why and where we use "out" keyword and the significance of it. Thanks in advance

推荐答案

out关键字仅表示参数是通过引用而不是通过值传递的.这基本上意味着被调用的方法可以更改值.看看MSDN页面 out(C#) [ ^ ]示例和更清晰的解释.

The out keyword just means that the parameter is passed by reference rather than by value. This basically means that the called method can change the value. Take a look at the MSDN page out(C#)[^] for examples and clearer explanation.

除了Wayne解释的内容:

关键字out还表示参数应该更改方法实现中的值.下面的代码示例显示了这种约束，并解释了ref和out之间的本质区别；两种模式均为参考:

In addition to what Wayne explains:

The keyword out also says that the parameter should change the value in the method implementation. The code sample below shows that constraint and explains essential difference between ref and out; both modes are by-reference:

struct MyStructure { /*...*/ }

struct SomeType {
    void SomeMethod(ref MyStructure reference) { } //does nothing, but it will compile
    void SomeBadMethod(out MyStructure reference) { } //will not compile because out parameter is not assigned
    void FixedMethod(out MyStructure reference) {
        //...
        out = new MyStructure(/*...*/); //this will fix the above method, will compile
    }
}

另外，不需要调用代码来初始化用作out参数的变量(因为它将由于调用而被初始化).

—SA

Also, a calling code is not required to initialize a variable used as out parameter (as it will be initialized as a result of the call).

—SA

您尝试使用Google搜索吗?我找到了这些:
http://msdn.microsoft.com/en-us/library/t3c3bfhx (v = vs.80).aspx [ http://msdn.microsoft.com/en-us/library/aa645764 (v = vs.71).aspx [

Did you try Googling this? I found these:
http://msdn.microsoft.com/en-us/library/t3c3bfhx(v=vs.80).aspx[^]
http://msdn.microsoft.com/en-us/library/aa645764(v=vs.71).aspx[^]

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