自己测试一下就行了:
Dim r As DataRow = e.DataRow
Select Case e.DataCol.Name
Case "数量","零售单价","会员单价"
Dim v As Integer = r("消费单号")
Dim dr As DataRow = DataTables("客户消费单").Find("消费单号 = " & v)
If r("会员卡号") IsNot Nothing Then
messagebox.show("Not Nothing")
r("价格合计") = r("零售单价")*r("数量")
r("会员价合计") = r("会员单价")*r("数量")
r("打折后合计") = r("零售单价")*r("数量")*r("折扣")
Forms("销售前台").Controls("TextBox9").value = dr("价格合计")
Forms("销售前台").Controls("TextBox10").value = dr("打折后合计")
Forms("销售前台").Controls("TextBox16").value = dr("会员价合计")
Forms("销售前台").Controls("TextBox12").value = dr("打折后合计") + dr("会员价合计")
Else
messagebox.show("Nothing")
r("价格合计") = r("零售单价")*r("数量")
r("会员价合计") = 0
r("打折后合计") = 0
Forms("销售前台").Controls("TextBox9").value = dr("价格合计")
Forms("销售前台").Controls("TextBox10").value = dr("打折后合计")
Forms("销售前台").Controls("TextBox16").value = dr("会员价合计")
Forms("销售前台").Controls("TextBox12").value = dr("价格合计")
End If
End Select