主题：关于日期计算问题

Dim dt_xyk As DataTable = DataTables("信用卡")
Dim dt_lsz As DataTable = DataTables("流水账")
Dim dt_dyyh As DataTable = DataTables("当月应还")
dt_dyyh.DataRows.Clear
For Each dr As DataRow In dt_xyk.DataRows
    Dim ndr As DataRow = dt_dyyh.AddNew
    ndr("账户名称") = dr("账户名称")
    Dim d As Date = new Date(Date.Today.year, Date.Today.Month, 1)
    ndr("账单日") = d.AddDays(dr("账单日")-1)
    ndr("转出") = dt_lsz.Compute("sum(金额)", "账户名称 = '" & ndr("账户名称") & "' and 日期 <= #" & ndr("账单日") & "# and 类别 = '转出'")
    ndr("转入") = dt_lsz.Compute("sum(金额)", "账户名称 = '" & ndr("账户名称") & "' and 日期 <= #" & ndr("账单日") & "# and 类别 = '转入'")
    ndr("信用额度") = dr("信用额度")
    ndr("当月应还") = ndr("转出") - ndr("转入")
    ndr("可用额度") = ndr("信用额度") - ndr("转出") + ndr("转入")
    If val(dr("还款日")) < val(dr("账单日")) Then
        ndr("还款日") = d.AddDays(dr("还款日")-1).AddMonths(1)
    Else
        ndr("还款日") = d.AddDays(dr("还款日")-1)
    End If
Next
e.Form.Controls("Table1").Table.DataSource = DataTables("当月应还")