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Asked: 2026-05-25T11:41:15+00:00

I am writing a DataTable to xml with the DataTable.WriteXml()-method. This takes a few

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I am writing a DataTable to xml with the DataTable.WriteXml()-method. This takes a few seconds, which I think is very good.

However, reading the file (38MB size, 26000rows, 36 columns) using the ReadXml()-method takes 3 minutes! I am already using the DataTable.BeginLoadData() method before calling the ReadXml (which made it ~10 seconds faster), but is there anything else I can do to improve performance?

Here is the loading method:

            data = new DataTable();
            data.BeginLoadData();
            data.ReadXml(filedialog.FileName);
            data.EndLoadData();

I have used breakpoints and stopwatch to see that it is actually the ReadXml method that is the time consuming part.

Here is the XML scheme:

<?xml version="1.0" standalone="yes"?>
<xs:schema id="NewDataSet" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
  <xs:element name="NewDataSet" msdata:IsDataSet="true" msdata:MainDataTable="ReportTable" msdata:UseCurrentLocale="true">
    <xs:complexType>
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <xs:element name="ReportTable">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="Task" type="xs:int" minOccurs="0" />
              <xs:element name="Project" type="xs:string" minOccurs="0" />
              <xs:element name="DP" type="xs:string" minOccurs="0" />
              <xs:element name="Requester" type="xs:string" minOccurs="0" />
              <xs:element name="TaskType" type="xs:string" minOccurs="0" />
              <xs:element name="OriginalMethod" type="xs:string" minOccurs="0" />
              <xs:element name="Method" type="xs:string" minOccurs="0" />
              <xs:element name="Country" type="xs:string" minOccurs="0" />
              <xs:element name="DayPosted" type="xs:string" minOccurs="0" />
              <xs:element name="DayFinished" type="xs:string" minOccurs="0" />
              <xs:element name="Posted" type="xs:dateTime" minOccurs="0" />
              <xs:element name="JustifiedPosted" type="xs:dateTime" minOccurs="0" />
              <xs:element name="Due" type="xs:dateTime" minOccurs="0" />
              <xs:element name="DueInSec" type="xs:double" minOccurs="0" />
              <xs:element name="AvailableDPWorkTime" type="xs:double" minOccurs="0" />
              <xs:element name="AvailableWorkHours" type="xs:string" minOccurs="0" />
              <xs:element name="StartedDate" type="xs:dateTime" minOccurs="0" />
              <xs:element name="FinishDate" type="xs:dateTime" minOccurs="0" />
              <xs:element name="SecUsed" type="xs:double" minOccurs="0" />
              <xs:element name="MinsUsed" type="xs:double" minOccurs="0" />
              <xs:element name="HoursUsed" type="xs:double" minOccurs="0" />
              <xs:element name="TimeUsed" type="xs:string" minOccurs="0" />
              <xs:element name="Month" type="xs:string" minOccurs="0" />
              <xs:element name="Experience" type="xs:int" minOccurs="0" />
              <xs:element name="Delay" type="xs:string" minOccurs="0" />
              <xs:element name="SecDelay" type="xs:int" minOccurs="0" />
              <xs:element name="TimeDelayed" type="xs:string" minOccurs="0" />
              <xs:element name="PostedVsDue" type="xs:string" minOccurs="0" />
              <xs:element name="Modified" type="xs:dateTime" minOccurs="0" />
              <xs:element name="AvailableDPModWorkTime" type="xs:double" minOccurs="0" />
              <xs:element name="ModifiedAvailableWorkHours" type="xs:string" minOccurs="0" />
              <xs:element name="MasterProject" type="xs:string" minOccurs="0" />
              <xs:element name="Year" type="xs:string" minOccurs="0" />
              <xs:element name="Department" type="xs:string" minOccurs="0" />
              <xs:element name="Customer" type="xs:string" minOccurs="0" />
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:choice>
    </xs:complexType>
  </xs:element>
</xs:schema>
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1 Answer

  1. Editorial Team

    I had same problem long ago, solved by setting EnforceConstraints to false, readXml then set it back to true.

    Try it out.

    Here the docs http://msdn.microsoft.com/en-us/library/s3bxwk8b(v=vs.80).aspx

    EDIT:

    user is loading data into a DataTable directly, suggested also to load data in a stream so to isolate network/disk performance issue from the pure call to data.ReadXml(...);

    ReadXml has aso an overload to read from a stream which could be used after data has been loaded in a Stream.

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