The PropertyCollection can be accessed through the ExtendedProperties property of the DataColumn, DataSet, or DataTable class.

Add custom properties to the DataColumn, DataSet, or DataTable objects through the PropertyCollection. For example, you may want to store the time of the object's creation for later comparison to another object.

The following example creates a timestamp value for a DataTable and adds it to the PropertyCollection.

Private Sub AddTimeStamp()
    'Create a new DataTable.
    Dim table As New DataTable("NewTable")

    'Get its PropertyCollection.
    Dim properties As PropertyCollection = table.ExtendedProperties

    'Add a timestamp value to the PropertyCollection.
    properties.Add("TimeStamp", DateTime.Now)

    'Print the timestamp.
    Console.WriteLine(properties("TimeStamp"))
End Sub 

private void AddTimeStamp()
{
    //Create a new DataTable.
    DataTable table = new DataTable("NewTable");

    //Get its PropertyCollection.
    PropertyCollection properties = table.ExtendedProperties;

    //Add a timestamp value to the PropertyCollection.
    properties.Add("TimeStamp", DateTime.Now);

    // Print the timestamp.
    Console.WriteLine(properties["TimeStamp"]);
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

.NET Framework

.NET Compact Framework

XNA Framework

Reference