主题：计算工时的难题，同一天多次出工，只计算一次。附例子

相当复杂:

Dim dic As New Dictionary(of Date,List(of String))
Dim dic2 As new Dictionary(of String,Integer)
For Each dr As DataRow In DataTables("表A").DataRows
    Dim dt As Date = dr("工程时间")
    Dim lst As List(of String)
    If dic.ContainsKey(dt) = False
        lst = new List(of String)
        dic.add(dt,lst)
    Else
        lst = dic(dt)
    End If
    Dim nms() As String = dr("参与员工").Split(",")
    For Each nm As String In nms
        If lst.Contains(nm) = False Then
            lst.Add(nm)
        End If
    Next
Next
For Each lst As List(of String) In dic.Values
    For Each nm As String In lst
        If dic2.ContainsKey(nm) = False Then
            dic2.Add(nm,1)
        Else
            dic2(nm) = dic2(nm) + 1
        End If
    Next
Next
For Each nm As String In dic2.Keys
    output.show(nm & ":" & dic2(nm))
Next