為什么在 C# 中檢測到無法訪問的代碼 - 將三元運算嵌套到 if-else 語句中

Question

在此之前，我是c#的初學者。我將嵌套三元運算改成獨立語句，但是當我將它改成if-else語句時，它說它是無法訪問的代碼

這是我遇到問題的行

FlowLineSize = sumOfAllWells,
NoOfWell = _brainConceptDCDetailsInput.HydrocacbornType == "Gas"
    ? _brainConceptDCDetailsInput.GasFlowlineSize
    : _brainConceptDCDetailsInput.HydrocacbornType == "Oil"
        ? _brainConceptDCDetailsInput.OilFlowlineSize
        : 0

在sumOfAllWells,之后放置 if else 語句的語法格式是什么，我已經嘗試在它之后放置 if 語句並且它說無法訪問代碼

編輯：

這是完整的代碼，

public BrainSubseaJumperInputDTO FillInputDTO(ProjectInfoDTO projectInfoInput = null, BrainConceptsInputDTO conceptInput = null)
{
    var sumOfAllWells = conceptInput?.ConceptDCDetailsInputDTO
        .Sum(x => x.OilProducerWell + x.GasProducerWell + x.WaterInjectorWell + x.GasInjectorWell) ?? 0;
    return new BrainSubseaJumperInputDTO()
    {
        FlowLineSize = sumOfAllWells,
        NoOfWell = _brainConceptDCDetailsInput.HydrocacbornType == "Gas"
            ? _brainConceptDCDetailsInput.GasFlowlineSize
            : _brainConceptDCDetailsInput.HydrocacbornType == "Oil"
                ? _brainConceptDCDetailsInput.OilFlowlineSize
                : 0
    };
}

Answer 1

如果這是有效代碼： 編輯后，它更有意義......

FlowLineSize = sumOfAllWells, // <== Typo here? No, it's part of something bigger
NoOfWell = _brainConceptDCDetailsInput.HydrocacbornType == "Gas" ?
                            _brainConceptDCDetailsInput.GasFlowlineSize :
                            _brainConceptDCDetailsInput.HydrocacbornType == "Oil" ? 
                                 _brainConceptDCDetailsInput.OilFlowlineSize 
                                 :0

那么三元可憎性將大致轉化為

if( _brainConceptDCDetailsInput.HydrocacbornType == "Gas")
{
    NoOfWell = _brainConceptDCDetailsInput.GasFlowlineSize;
}
else
{
    if(_brainConceptDCDetailsInput.HydrocacbornType == "Oil")
    { 
        NoOfWell = _brainConceptDCDetailsInput.OilFlowlineSize;
    }
    else
    {
        NoOfWell = 0;
    }
}

假設有一個NoOfWell聲明。

但正如評論中指出的那樣：有更好的（即更清晰、更易讀）的方式來表達這一點。

例如 switch 表達式：

NoOfWell = _brainConceptDCDetailsInput.HydrocarbonType switch 
{ 
    "Gas" => _brainConceptDCDetailsInput.GasFlowlineSize, 
    "Oil" => _brainConceptDCDetailsInput.OilFlowlineSize, 
    _ => 0 
}

如果您可以將HydroCarbonType class，那么這可能是它的一個屬性。

如果您可以將其設為枚舉，則可以使用 Dictionary 和 ExtentionMethods ...

---

看到完整的代碼后，您還可以將邏輯部分作為 DTO 構建器/工廠的一部分……

static BrainSubseaJumperInputDTO FromBrainConceptDetailsInput( 
                                     int sum, 
                                     WhateverTypeThatIs input )
{
    return new BrainSubseaJumperInputDTO(){
        FlowLineSize = sum,
        NoOfWell = input.HydrocarbonType switch 
                   { 
                       "Gas" => input.GasFlowlineSize, 
                       "Oil" => input.OilFlowlineSize, 
                       _ => 0 
                   }
    };
}

這會將您的代碼歸結為

public BrainSubseaJumperInputDTO FillInputDTO(ProjectInfoDTO projectInfoInput = null, BrainConceptsInputDTO conceptInput = null)
{
    var sumOfAllWells = conceptInput?.ConceptDCDetailsInputDTO
                                     .Sum(x => x.OilProducerWell + 
                                               x.GasProducerWell + 
                                               x.WaterInjectorWell + 
                                               x.GasInjectorWell) 
                                     ?? 0;
    return FromBrainConceptDetailsInput( sumOfAllWells, 
                                         _brainConceptDCDetailsInput);
}