我有以下结构的 JSON:
[
{
"ID": 1,
"Label": "Reg Scheme",
"Colours": [
{
"ID": 1,
"Value": "0x3333cc",
"Result": 1,
"Label": null
},
{
"ID": 2,
"Value": "0x666699",
"Result": 2,
"Label": null
},
{
"ID": 3,
"Value": "0x009966",
"Result": 3,
"Label": null
}
]
},
{
"ID": 2,
"Label": "Spesh Scheme",
"Colours": [
{
"ID": 11,
"Value": "0x59699c",
"Result": 1,
"Label": null
},
{
"ID": 12,
"Value": "0x0070ff",
"Result": 2,
"Label": null
},
{
"ID": 13,
"Value": "0x90865e",
"Result": 3,
"Label": null
}
]
},
我有一个实体数据集，我在其中加入了所有相关信息，并尝试通过单个 linq-to-sql EF 查询生成具有该结构的 JSON 以返回到 webapi 方法。
到目前为止我的查询是:
return
DbContext.Schemes
.Join(
DbContext.SchemeColours,
s => s.SchemeID,
sc => sc.SchemeID,
(s, sc) => new
{
s.SchemeID,
s.Label,
sc.Colour,
sc.Result,
sc.ColourID
})
.Select(a =>
new Overlay.ReportColourScheme
{
ID = a.SchemeID,
Label = a.Label,
Colours = new List<Overlay.ReportColour>
{
new Overlay.ReportColour
{
ID = a.ColourID,
Value = a.Colour,
Result = a.Result
}
}
})
.ToArray();
几乎是这样，但还不完全是:
[
{
"ID": 1,
"Label": "Regular Scheme",
"Colours": [
{
"ID": 1,
"Value": "0x3333cc",
"Result": 1,
"Label": null
}
]
},
{
"ID": 1,
"Label": "Regular Scheme",
"Colours": [
{
"ID": 2,
"Value": "0x666699",
"Result": 2,
"Label": null
}
]
},
{
"ID": 1,
"Label": "Regular Scheme",
"Colours": [
{
"ID": 3,
"Value": "0x009966",
"Result": 3,
"Label": null
}
]
},
{
"ID": 2,
"Label": "Protanopia adjusted Scheme",
"Colours": [
{
"ID": 11,
"Value": "0x59699c",
"Result": 1,
"Label": null
}
]
},
{
"ID": 2,
"Label": "Protanopia adjusted Scheme",
"Colours": [
{
"ID": 12,
"Value": "0x0070ff",
"Result": 2,
"Label": null
}
]
},
{
"ID": 2,
"Label": "Protanopia adjusted Scheme",
"Colours": [
{
"ID": 13,
"Value": "0x90865e",
"Result": 3,
"Label": null
}
]
},
当然，它会为每个 resultID 创建一个新列表。顶级 ID 是一个 SchemeID——我正在寻找的逻辑如下:“使用特定的 schemeID 获取前 3 个结果，将它们添加到 Colours 列表中，然后转到下一个 schemeID”
我相信这会产生与我开始发布时使用的相同的 JSON。
如有任何帮助，我们将不胜感激，谢谢。
最佳答案
试试下面的代码:
return
DbContext.Schemes
.Join(
DbContext.SchemeColours,
s => s.SchemeID,
sc => sc.SchemeID,
(s, sc) => new
{
s.SchemeID,
s.Label,
sc.Colour,
sc.Result,
sc.ColourID
})
// After joining you group by SchemeID, in this way you have
// for each SchemeID the group of related items
.GroupBy(a => a.SchemeID)
// You then create your result, starting from the main object
.Select(g =>
new Overlay.ReportColourScheme
{
ID = g.Key,
// I suppose you have at least a child for each SchemeID,
// otherwise you can check if the list is empty
Label = g.FirstOrDefault().Label,
// For each group you create a list of child object
Colours = g.Select(v => new Overlay.ReportColour
{
ID = v.ColourID,
Value = v.Colour,
Result = v.Result
}).ToList()
})
.ToArray();
关于c# linq-to-sql EF 查询以匹配特定的 JSON 结构，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/39899847/