问题描述
I was just curious about this: the following code will not compile, because we cannot modify a foreach iteration variable:
foreach (var item in MyObjectList)
{
item = Value;
}
But the following will compile and run:
foreach (var item in MyObjectList)
{
item.Value = Value;
}
Why is the first invalid, whereas the second can do the same underneath (I was searching for the correct english expression for this, but I don't remember it. Under the...? ^^ )
foreach is a read only iterator that iterates dynamically classes that implement IEnumerable, each cycle in foreach will call the IEnumerable to get the next item, the item you have is a read only reference, you can not re-assign it, but simply calling item.Value is accessing it and assigning some value to a read/write attribute yet still the reference of item a read only reference.
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