我在silverlight应用程序中有一个比较2个字符串的条件,由于某种原因,当我使用==时,它返回false而. equals()返回true。

代码如下:

if (((ListBoxItem)lstBaseMenu.SelectedItem).Content.Equals("Energy Attack"))
{
    // Execute code
}

if (((ListBoxItem)lstBaseMenu.SelectedItem).Content == "Energy Attack")
{
    // Execute code
}

你知道为什么会这样吗?


当前回答

I am a bit confused here. If the runtime type of Content is of type string, then both == and Equals should return true. However, since this does not appear to be the case, then runtime type of Content is not string and calling Equals on it is doing a referential equality and this explains why Equals("Energy Attack") fails. However, in the second case, the decision as to which overloaded == static operator should be called is made at compile time and this decision appears to be ==(string,string). this suggests to me that Content provides an implicit conversion to string.

其他回答

= =操作符

如果操作数为值类型且值相等,则返回true否则为false。 如果操作数是引用类型(string除外),并且都引用同一个实例(同一对象),则返回true否则返回false。 如果操作数为字符串类型且值相等,则返回true否则返回false。

.Equals

如果操作数是引用类型,它执行引用相等,即如果两个操作数都引用同一个实例(同一个对象),则返回true否则返回false。 如果操作数是值类型,那么与==运算符不同,它首先检查它们的类型,如果它们的类型相同,它执行==运算符,否则返回false。

==

==运算符可用于比较任何类型的两个变量,它只是比较比特。

int a = 3;
byte b = 3;
if (a == b) { // true }

注意:在int的左边有更多的0,但我们在这里不关心它。

Int a(00000011) ==字节b (00000011)

记住==运算符只关心变量中比特的模式。

如果两个引用(原语)指向堆上的同一个对象,则使用==。

无论变量是引用还是原语,规则都是相同的。

Foo a = new Foo();
Foo b = new Foo();
Foo c = a;

if (a == b) { // false }
if (a == c) { // true }
if (b == c) { // false }

A == c是正确的 A == b是假的

a和c的位模式是相同的,所以使用==它们是相等的。

等于():

使用equals()方法查看两个不同的对象是否相等。

例如两个不同的String对象都表示“Jane”中的字符

据我所知,答案很简单:

==比较对象引用。 . equals比较对象内容。 字符串数据类型的作用总是类似于内容比较。

我希望我是对的,这回答了你的问题。

当我们创建任何对象时,对象有两个部分,一个是内容,另一个是对该内容的引用。 ==比较内容和引用; Equals()只比较内容

http://www.codeproject.com/Articles/584128/What-is-the-difference-between-equalsequals-and-Eq

I am a bit confused here. If the runtime type of Content is of type string, then both == and Equals should return true. However, since this does not appear to be the case, then runtime type of Content is not string and calling Equals on it is doing a referential equality and this explains why Equals("Energy Attack") fails. However, in the second case, the decision as to which overloaded == static operator should be called is made at compile time and this decision appears to be ==(string,string). this suggests to me that Content provides an implicit conversion to string.