VB.Net向/从XML文件读写DataTable [英] VB.Net write and read DataTable to/from XML-file

问题描述

我正在尝试将DataTable写入XML文件，然后使用以下VB.Net代码将数据从XML文件读取到另一个DataTable，我收到错误消息： DataTable不支持架构推断来自Xml。：

I'm trying to write a DataTable to an XML-file and read afterwards the data from the XML-file to another DataTable with the following VB.Net code, I'm getting the error "DataTable does not support schema inference from Xml.":

dt1.WriteXml(fileName:=xf, writeHierarchy:=True)  
Dim dt2 = New Data.DataTable(dt1.TableName)  
dt2 = ds.Tables(0)  
dt2.ReadXml(fileName:=xf)  

我可以通过将文件读入DataSet来解决我的问题，但我想了解其中的区别：

I could solve my problem with read the file into a DataSet, but I would like to understand the difference:

Dim ds = New Data.DataSet()  
ds.ReadXml(fileName:=xf)  
Dim dt2 = ds.Tables(0)  

有人可以告诉我吗？

推荐答案

我知道很久以前就问过这个问题，但是几天前我也遇到了同样的问题。

I know this question asked long time ago, but I had same problem few days ago.

您必须设置 TableName DataTable 的c $ c>在导出之前（写 xml ）。

You have to set TableName for DataTable before exporting (writing xml).

示例：

    dt1.TableName = "MyDataTable"
    dt1.WriteXmlSchema(Application.StartupPath + "\test_sh.xml", True)
    dt1.WriteXml(Application.StartupPath + "\test_dt.xml", True)

然后读取（从 xml 导入）回到新的 DataTable 中：

And, for read (import from xml) back in new DataTable :

    dt2 = New DataTable
    dt2.ReadXmlSchema(Application.StartupPath + "\test_sh.xml")
    dt2.ReadXml(Application.StartupPath + "\test_dt.xml")

然后填充您的 GridView 或您还需要什么。

And then populate Your GridView or what else You need.

TableName dt2 将自动从架构文件（ test_sh.xml ）中提取。在这种情况下， MyDataTable 就像在 dt1.TableName 中设置的一样。

TableName for dt2 will be automatically pulled from schema file (test_sh.xml). In this case MyDataTable, like was set in dt1.TableName.

保存 schema 也是重要，否则您将无法阅读 xml 返回表格。

It's important to save schema, too, or You can't read xml back in table.

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