Dim doc As New PrintDoc
Dim rt As New prt.RenderTable
Dim cmd As New SQLCommand \'定义一个SQL命令
Dim dt As DataTable \'定义一个数据表变量
Dim Count As Integer = 0
cmd.CommandText = "Select * From {订单} Where Year(日期) = 2009 And Month(日期) = 6"
dt = cmd.ExecuteReader() \'生成一个临时表
For Each Col AS DataCol In Dt.DataCols
    rt.Cells(0,Count).Text = Col.Name
    For r As integer = 0 To dt.DataRows.Count - 1
        rt.Cells(r +1,Count).Text = dt.DataRows(r)(Col.Name)
    Next
    Count = Count + 1
Next
rt.Style.Gridlines.All = New prt.Linedef(Color.Gray) \'灰色网格线
rt.CellStyle.Spacing.All = 1 \'内容距离网格线1毫米
rt.Rows(0).Style.TextAlignHorz = prt.AlignHorzEnum.Center \'第一行内容水平居中
doc.Body.Children.Add(rt)
doc.Preview()

日期列为空，打印显示为0：00：00

如何使打印显示也为空呢？

都会打印后台数据了，加个判断应该不难吧：

IsNull

判断某一列的内容是否为空。

例如：