How can find the min X of List of point2d?

[Stakin]

I want to query and group some 2D points, such as find the maxmum X coordinate in the point, find the points with the maxmum X coordinate, but when I query with linq, the code error and cannot run.Can someone help me out? thanks!
The error message is as follows：

Conversion From Type 'GroupedResultEnumerable(Of Point2d,Double,VB$AnonymousType_0(Of Double,Double))' to type 'IWin32Window' is not valid.

the code is as follows：

Sub Main
		Dim oTG As Inventor.TransientGeometry = ThisApplication.TransientGeometry
		Dim oPt2d As New List(Of Point2d)
		For i As Integer = 1 To 100
			oPt2d.Add(oTG.CreatePoint2d(Int(99*Rnd)+1,Int(99*Rnd)+1))
		Next
		Dim oRad 'As Double		
		oRad=From oPt As Point2d In oPt2d.Cast(Of Point2d)
                      Group By oPt.X
                      Into oMax = Max(Abs(oPt.X))
		MessageBox.Show(oRad, "Title")					  
		Dim oMaxXPt2d As List(Of Point2d)
		oMaxXPt2d=oPt2d.Cast(Of Point2d).Select(Function(p As Point2d) p.X=oRad).ToList
End Sub

[Michael.Navara]

The reason is the method MessageBox.Show is overloaded. The first argument should be of type string or IWin32Window.

Convert your variable oRad to string and it cen resolve your issue.