将 LINQ C# 转换为 VB.NET

Question

我正在处理这个怪物：

public static IEnumerable<Warp> GetWarps(IEnumerable<Point> sourcePoints, IEnumerable<Point> destPoints, IEnumerable<Triangle> destTriangles)
{
// build lists of source and destination landmark points
var sourceList = sourcePoints.ToList();
var destList = destPoints.ToList();
// find all three triangle points in the list of destination landmark points
var indices = from t in destTriangles
let p1 = destPoints.First(p => Math.Abs(p.X - t.P1.X) < 1 && Math.Abs(p.Y - t.P1.Y) < 1)
let p2 = destPoints.First(p => Math.Abs(p.X - t.P2.X) < 1 && Math.Abs(p.Y - t.P2.Y) < 1)
let p3 = destPoints.First(p => Math.Abs(p.X - t.P3.X) < 1 && Math.Abs(p.Y - t.P3.Y) < 1)
select new {
X1 = destList.IndexOf(p1),
X2 = destList.IndexOf(p2),
X3 = destList.IndexOf(p3)
};
// return enumeration of warps from source to destination triangles
return from x in indices
select new Warp(
new Triangle(sourceList[x.X1], sourceList[x.X2], sourceList[x.X3]),
new Triangle(destList[x.X1], destList[x.X2], destList[x.X3]));
}

我已经尝试了很多，但我没有处理语法和陷阱的经验。

我自己的方法都失败了，我不知道我是否走在正确的方向上：

Function GetWarps(ByVal sourcePoints As IEnumerable(Of Point), ByVal destPoints As IEnumerable(Of Point), ByVal destTriangles As IEnumerable(Of Triangle)) As IEnumerable(Of Warp)
Dim sourceList = sourcePoints.ToList()
Dim destList = destPoints.ToList()
Dim p1 As Triangle
Dim p2 As Triangle
Dim p3 As Triangle
Dim indices = From t In destTriangles 
p1 = destPoints.First(Function(p) Math.Abs(p.X - t.P1.X) < 1 AndAlso Math.Abs(p.Y - t.P1.Y) < 1) 
p2 = destPoints.First(Function(p) Math.Abs(p.X - t.P2.X) < 1 AndAlso Math.Abs(p.Y - t.P2.Y) < 1) 
p3 = destPoints.First(Function(p) Math.Abs(p.X - t.P3.X) < 1 AndAlso Math.Abs(p.Y - t.P3.Y) < 1) Select
(
.X1 = destList.IndexOf(p1), Key,
.X2 = destList.IndexOf(p2), Key,
.X3 = destList.IndexOf(p3), Key,
)
Return From x In indices Select New Warp(New Triangle(sourceList(x.X1), sourceList(x.X2), sourceList(x.X3)), New Triangle(destList(x.X1), destList(x.X2), destList(x.X3)))
End Function

谁能告诉我如何正确地做到这一点？

谢谢！！

Answer 1

我明白了！！ ：-(

Public Function GetWarps(ByVal sourcePoints As IEnumerable(Of Point), ByVal destPoints As IEnumerable(Of Point), ByVal destTriangles As IEnumerable(Of Triangle)) As IEnumerable(Of Warp)
' build lists of source and destination landmark points
Dim sourceList = sourcePoints.ToList()
Dim destList = destPoints.ToList()
' find all three triangle points in the list of destination landmark points
Dim indices = From t In destTriangles _
Let p1 = destPoints.First(Function(p) Math.Abs(p.X - t.P1.X) < 1 AndAlso Math.Abs(p.Y - t.P1.Y) < 1) Let p2 = destPoints.First(Function(p) Math.Abs(p.X - t.P2.X) < 1 AndAlso Math.Abs(p.Y - t.P2.Y) < 1) Let p3 = destPoints.First(Function(p) Math.Abs(p.X - t.P3.X) < 1 AndAlso Math.Abs(p.Y - t.P3.Y) < 1) _
Select New With {Key .X1 = destList.IndexOf(p1), Key .X2 = destList.IndexOf(p2), Key .X3 = destList.IndexOf(p3)}
' return enumeration of warps from source to destination triangles
Return From x In indices _
Select New Warp(New Triangle(sourceList(x.X1), sourceList(x.X2), sourceList(x.X3)), New Triangle(destList(x.X1), destList(x.X2), destList(x.X3)))
End Function

Answer 2

试试这个

Public Shared Function GetWarps(ByVal sourcePoints As IEnumerable(Of Point), ByVal destPoints As IEnumerable(Of Point), ByVal destTriangles As IEnumerable(Of Triangle)) As IEnumerable(Of Warp)
Dim sourceList = sourcePoints.ToList()
Dim destList = destPoints.ToList()
Dim indices = From t In destTriangles Let p1 = destPoints.First(Function(p) Math.Abs(p.X - t.P1.X) < 1 AndAlso Math.Abs(p.Y - t.P1.Y) < 1) Let p2 = destPoints.First(Function(p) Math.Abs(p.X - t.P2.X) < 1 AndAlso Math.Abs(p.Y - t.P2.Y) < 1) Let p3 = destPoints.First(Function(p) Math.Abs(p.X - t.P3.X) < 1 AndAlso Math.Abs(p.Y - t.P3.Y) < 1) Select New With {Key
.X1 = destList.IndexOf(p1), Key
.X2 = destList.IndexOf(p2), Key
.X3 = destList.IndexOf(p3)
}
Return From x In indices Select New Warp(New Triangle(sourceList(x.X1), sourceList(x.X2), sourceList(x.X3)), New Triangle(destList(x.X1), destList(x.X2), destList(x.X3)))
End Function