[英]how can i modify a value in list<t>?
class SomeClass
{
private struct PhraseInfo
{
public int Start;
public int Length;
}
...
private void SomeMethod(...)
{
List<PhraseInfo> posesBracket = new List<PhraseInfo>();
posesBracket.Add(new PhraseInfo());
posesBracket[0].Start = 10;
}
of cause, posesBracket[0].start=10; of cause,posesBracket [0] .start = 10; occur compiler error CS1612 : "Cannot modify the return value of 'expression' because it is not a variable" 发生编译器错误CS1612:“无法修改'表达式'的返回值,因为它不是变量”
how can i modify a value in list? 我怎样才能修改列表中的值?
The problem is that PhraseInfo is a value type, so the this[] method will return a value, not a reference, to solve it, do this: 问题是PhraseInfo是一个值类型,所以this []方法将返回一个值而不是一个引用来解决它,执行以下操作:
PhraseInfo pi = posesBracket[0];
pi.Start = 10;
posesBracket[0] = pi;
var temp = posesBracket[0];
temp.Start = 10;
posesBracket[0] = temp;
You cannot have a struct defined as a method. 您不能将结构定义为方法。 And as they say, you need the reference to change values. 正如他们所说,你需要改变价值观的参考。 So it goes like this: 所以它是这样的:
class SomeClass
{
private struct PhraseInfo
{
public int Start;
public int Length;
}
private void somemethod()
{
List<PhraseInfo> posesBracket = new List<PhraseInfo>();
posesBracket.Add(new PhraseInfo());
PhraseInfo pi = posesBracket[0];
pi.Start = 10;
posesBracket[0] = pi;
}
}
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