Question

我有一个XML元素，其DateTimeOffset中的值为2099-12-31T23:59:58.576+13:00。

运行myDS.ReadXml(myStream, XmlReadMode.InferTypedSchema)会得到Specified cast is not valid.Couldn't store <2019-12-31 23:59:58> in MyColDTO Column. Expected type is DateTimeOffset.

附加的偏移量应清楚地指示DateTimeOffset而不是DateTime。

为什么DotNet（FW 4.6.2）不能正确识别它？有简单的方法可以解决吗？

====自包含的vb.net单元测试===

<TestMethod()> Public Sub THC2398_ReadXml_Bug()
Dim ds1 As DataSet, ds2 As DataSet, dt1 As DataTable, dt2 As DataTable, dr As DataRow, dtoAt As DateTimeOffset = DateTimeOffset.Parse("2019-12-31T23:59:58.576+13:00")

Assert.AreEqual("v4.0.30319", GetType(String).Assembly.ImageRuntimeVersion, "Version check")
Assert.AreEqual("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089", GetType(String).Assembly.FullName, "Version check")

ds1 = New DataSet("ds")
dt1 = New DataTable("dt")
ds1.Tables.Add(dt1)
dt1.Columns.Add(New DataColumn("MyColDTO", GetType(DateTimeOffset)))
dr = dt1.NewRow
dr("MyColDTO") = dtoAt
dt1.Rows.Add(dr)
Assert.AreEqual(1, dt1.Rows.Count)
Assert.AreEqual("DateTimeOffset", dt1.Rows(0)(0).GetType.Name)

Dim tw As IO.TextWriter = New StringWriter, tr As TextReader
dt1.WriteXml(tw, XmlWriteMode.IgnoreSchema)
System.Console.WriteLine(tw.ToString)

tr = New StringReader(tw.ToString)
ds2 = New DataSet("ds")
ds2.ReadXml(tr, XmlReadMode.InferTypedSchema)
dt2 = ds2.Tables("dt")
Assert.AreEqual(1, dt2.Rows.Count)
'Assert.AreEqual("DateTimeOffset", dt2.Rows(0)(0).GetType.Name, "this was expected")
Assert.AreEqual("DateTime", dt2.Rows(0)(0).GetType.Name, "*BUG* WHAT?! how can you tell me that 2099-12-31T23:59:58.576+13:00 is a DateTime?")

For Each item As DataRow In dt2.Rows
    dr = dt1.NewRow
    Try
        dr.ItemArray = item.ItemArray
    Catch ex As ArgumentException
        Assert.AreEqual("Specified cast is not valid.Couldn't store <2019-12-31 23:59:58> in MyColDTO Column.  Expected type is DateTimeOffset.", ex.Message, "Confirm that the bug is giving its bad message")
        Assert.Fail("This should not have happened")
    End Try
    dt1.Rows.Add(dr)
Next
End Sub

控制台的输出：

<ds>
  <dt>
    <MyColDTO>2019-12-31T23:59:58.576+13:00</MyColDTO>
  </dt>
</ds>

Answer 1

答案是..因为数据集不支持DateTimeOffset DataColumn.DataType Property。但是.. SQL Server可以datetimeoffset (Transact-SQL)

似乎Microsoft软件与其自身不兼容。

为什么DotNet XmlReadMode.InferTypedSchema将DateTimeOffset视为DateTime？

1 个答案: