主题：[求助]如何根据相对位置确定其坐标?

For Each dr As DataRow In DataTables("坐标").Select("顶上控件 Is Null")
    Dim dr1 As DataRow = dr
    dr1("y坐标") = 0
    Do
        Dim dr2 As DataRow  = DataTables("坐标").Find("顶上控件 = '" & dr1("名称") & "'")
        If dr2 IsNot  Nothing
            dr2("y坐标") = dr("y坐标") + dr1("高")
            dr1 = dr2
        Else
            Exit Do
        End If
    Loop
Next
For Each dr As DataRow In DataTables("坐标").Select("左侧控件 Is Null")
    Dim dr1 As DataRow = dr
    dr1("x坐标") = 0
    Do
        Dim dr2 As DataRow  = DataTables("坐标").Find("左侧控件 = '" & dr1("名称") & "'")
        If dr2 IsNot  Nothing
            dr2("x坐标") = dr("x坐标") + dr1("宽")
            dr1 = dr2
        Else
            Exit Do
        End If
    Loop
Next

我有点糊涂了，一般来说，有左侧控件或顶上控件中的任何一个，都可以确定这个控件的位置了，为什么BBB同时有左侧控件和顶上控件?

For Each dr As DataRow In DataTables("坐标").Select("顶上控件 Is Null")
    Dim dr1 As DataRow = dr
    dr1("y坐标") = 0
    Do
        Dim dr2 As DataRow  = DataTables("坐标").Find("顶上控件 = '" & dr1("名称") & "'")
        If dr2 IsNot  Nothing
            If dr2.IsNull("左侧控件")  Then
                dr2("X坐标") = dr1("X坐标")
            End If
            dr2("y坐标") = dr1("y坐标") + dr1("高")
            dr1 = dr2
        Else
            Exit Do
        End If
    Loop
Next
For Each dr As DataRow In DataTables("坐标").Select("左侧控件 Is Null")
    Dim dr1 As DataRow = dr
    dr1("x坐标") = 0
    Do
        Dim dr2 As DataRow  = DataTables("坐标").Find("左侧控件 = '" & dr1("名称") & "'")
        If dr2 IsNot  Nothing
            dr2("x坐标") = dr1("x坐标") + dr1("宽")
            If dr2.IsNull("顶上控件") Then
                dr2("Y坐标") = dr1("Y坐标")
            End If
            dr1 = dr2
        Else
            Exit Do
        End If
    Loop
Next