我对IL完全陌生,但是据我所知MoveNext
应该在Current
之前调用,可以说我们有这样的foreach语句:
foreach (var i in Enumerable.Empty<string>())
{
}
如果我们查看生成的IL,将会看到Current首先被调用:
IL_0014: br.s IL_001f
IL_0016: ldloc.1
IL_0017: callvirt instance !0 class [mscorlib]System.Collections.Generic.IEnumerator`1<string>::get_Current()
IL_001c: stloc.0
IL_001d: nop
IL_001e: nop
IL_001f: ldloc.1
IL_0020: callvirt instance bool [mscorlib]System.Collections.IEnumerator::MoveNext()
IL_0025: stloc.2
IL_0026: ldloc.2
IL_0027: brtrue.s IL_0016
IL_0029: leave.s IL_003b
问题是为什么?
最佳答案
IL_0014: br.s IL_001f
根据MSDN,
br.s
无条件地将控制权转移到目标指令(短格式)。
引用的地址是调用
MoveNext
的指令。IL_001f: ldloc.1
IL_0020: callvirt instance bool [mscorlib]System.Collections.IEnumerator::MoveNext()
关于c# - 为什么在GetCurrent之前调用IEnumerator.MoveNext?,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/32146619/