How to serialize a DataTable to a string?

Question

Recently I was in the need to serialize a DataTable as a string for further processing (storing in a file).

So I asked myself: How to serialize a DataTa

Answer 1

You can also do this.

DataTable dt = new DataTable()  
//... Fill Datatable from SQL or a thousand other places you have seen on the net.     
Response.ContentType = "text/xml";    
dt.WriteXml(Response.OutputStream);  
Response.Flush();
Response.End();

Documentation found at

http://msdn.microsoft.com/en-us/library/system.data.datatable.writexml(v=VS.100).aspx

Answer 2

I would suggest NOT to serialize the DataTable and use custom entities for persistence/contracts to avoid difference in implementation details between .Net versions. The XML schema of the DataTable class is undocumented implementation detail that you should not rely on.

Answer 3

Here is the code I wrote to perform the task of serializing a DataTable into a string:

public static string SerializeTableToString( DataTable table )
{
    if (table == null)
    {
        return null;
    }
    else
    {
        using (var sw = new StringWriter())
        using (var tw = new XmlTextWriter(sw))
        {
            // Must set name for serialization to succeed.
            table.TableName = @"MyTable";

            // --

            tw.Formatting = Formatting.Indented;

            tw.WriteStartDocument();
            tw.WriteStartElement(@"data");

            ((IXmlSerializable)table).WriteXml(tw);

            tw.WriteEndElement();
            tw.WriteEndDocument();

            // --

            tw.Flush();
            tw.Close();
            sw.Flush();

            return sw.ToString();
        }
    }
}

Hopefully this is useful for someone somewhere out there.

(Please note that I asked in the past whether it is OK to post snippets and got replies that this should be OK; correct me if I am wrong on that - thanks!)

Answer 4

You can also try writing out the DataTable to XML which works just as nicely:

Dim dt As DataTable
Dim DataTableAsXMLString As String
'...code to populate DataTable
Using sw As New StringWriter()       
    dt.WriteXml(sw)
    DataTableAsXMLString = sw.ToString()
End Using

...then if needed you can convert the XML right back to a DataTable:

Dim ds As New DataSet
Dim dt2 As DataTable
Using sr As New StringReader(DataTableAsXMLString)
    ds.ReadXml(sr)
    dt2 = ds.Tables(0)
End Using