我把目录树代码改为这样：

If e.Node.Level = 1 Then \'如果单击的是第二层节点
    Dim tr As Row = Tables("包装车间工资表").Current
    Dim dr As DataRow = e.Node.DataRow \'获取生成此节点的DataRow
    tr("产品名称规格") = dr("产品名称")
    tr("工序") = dr("工序")
    e.Form.DropDownBox.Value = tr("产品名称规格")
    e.Form.DropDownBox.CloseDropdown()
End If

查询按钮代码：

Dim txt As String = e.Form.DropDownBox.Text
If txt = "" Then
    Return
End If
Dim trv As WinForm.TreeView =  e.Form.Controls("TreeView1")
Dim Start As Integer
Dim idx As Integer = - 1
If trv.SelectedNode IsNot Nothing Then
    Dim FullName As String = trv.SelectedNode.FullName
    For i As Integer = 0 To trv.AllNodes.count - 1
        If trv.AllNodes(i).FullName = FullName  Then
            Start = i
            Exit For
        End If
    Next
End If
For i As Integer = Start + 1 To trv.AllNodes.count - 1
    Dim nd As WinForm.TreeNode = trv.AllNodes(i)
    If nd.Text.IndexOf(txt) >= 0 Then
        trv.SelectedNode = nd
        nd.EnsureVisible
        idx = i
        Exit For
    End If
Next
If  idx  = -1 Then \'如果没有找到下一个,从第一个开始
    For i As Integer = 0 To Start - 1
        Dim nd As WinForm.TreeNode = trv.AllNodes(i)
        If nd.Text.IndexOf(txt) >= 0 Then
            trv.SelectedNode = nd
            nd.EnsureVisible
            Exit For
        End If
    Next
End If
trv.Select()

依然不行

\'If e.DataCol.name = "单价" Then
    \'DataTables("包装车间工资表").datacols("产品名称规格").RaiseDataColChanged("产品名称规格 = \'" & e.DataRow("产品名称") & "\'")
\'End If

Select Case e.DataCol.name
    Case "产品名称规格", "工序"
        Dim fdr As DataRow = DataTables("价格表").find("产品名称 = \'" & e.DataRow("产品名称规格") & "\' and 工序 = \'" & e.DataRow("工序") & "\'")
        If fdr IsNot Nothing
            e.DataRow("单价") = fdr("单价")
        End If
End Select

把包装车间工资表中的表属性代码黄色部分注识掉就行了。