Q: Storing DataTable data in hard disk Is it possible to store the data in a DataTable in the hard disk instead of
the memory? By default, when a DataTable's being filled, the table (and
data) will remain in memory. Would it be possible to save this data in
another medium besides the memory? Everything would stay the same but
instead of filling up the DataTable by storing it in the memory, I'd be
storing it somewhere in the hard drive.

A: System.Data.DataTable implements ISerializable, so this is no big
challenge: the following example uses binary serialization
using System.Runtime.Serialization.Formatters.Binary;
[...]
//Create DataTable and Serialize
private void button1_Click(object sender, System.EventArgs e)
{
    DataTable dt = new DataTable();
    dt.Columns.Add("uid");
    dt.Columns.Add("test");
    
    for (int i = 0; i < 10; i++)
    {
        DataRow dr = dt.NewRow();
        dr[0] = i;
        dr[1] = string.Format("test{0}", i);
        dt.Rows.Add(dr);
    }

    FileStream fs = new FileStream(@"C:\test.bin", FileMode.Create);
    BinaryFormatter bf = new BinaryFormatter();
    bf.Serialize(fs, dt);
    fs.Close();
}

//Deserialize DataTable from File
private void button2_Click(object sender, System.EventArgs e)
{
    FileStream fs = new FileStream(@"C:\test.bin", FileMode.Open);
    BinaryFormatter bf = new BinaryFormatter();
    DataTable dt = (DataTable) bf.Deserialize(fs);
    fs.Close();
    
    foreach (DataRow dr in dt.Rows)
    {
        Debug.WriteLine(dr[0].ToString());
    }
}


A: The DataTable class has a method called WriteXml with many overloads that helps to write its content to disk
In its simplest form you could write this line
 myDataTable.WriteXml(somePathAndFileNameXML);

but, perhaps the better methods are the ones that allow to write also the schema data and the table data
  myDataTable.WriteXml.WriteXml(somePathAndFileNameXML, XmlWriteMode.WriteSchema);

The reverse is also possible with the ReadXml method

A: You can write it to disk and store it in a file or a database, but it has to be loaded in memory for your program to be able to interact with it.
