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DataTableCollection.CollectionChanging Event

Occurs while the DataTableCollection is changing because of DataTable objects being added or removed.

Namespace:  System.Data
Assembly:  System.Data (in System.Data.dll)

public event CollectionChangeEventHandler CollectionChanging

For more information about handling events, see Consuming Events.

The following example demonstrates how to use the CollectionChanging event.

public static void TableCollectionCollectionChanging()
{
    // Create a DataSet with two tables
    DataSet dataSet = new DataSet();

    // Assign the event-handler function for the  
    // CollectionChangeEvent.
    dataSet.Tables.CollectionChanging +=
        new System.ComponentModel.CollectionChangeEventHandler(
        Collection_Changing);

    // create Customer table
    DataTable customersTable = new DataTable("Customers");
    customersTable.Columns.Add("customerId",
        typeof(int)).AutoIncrement = true;
    customersTable.Columns.Add("name",
        typeof(string));
    customersTable.PrimaryKey = new DataColumn[] { customersTable.Columns["customerId"] };

    // create Orders table
    DataTable ordersTable = new DataTable("Orders");
    ordersTable.Columns.Add("orderId",
        typeof(int)).AutoIncrement = true;
    ordersTable.Columns.Add("customerId",
        typeof(int));
    ordersTable.Columns.Add("amount",
        typeof(double));
    ordersTable.PrimaryKey = new DataColumn[] { ordersTable.Columns["orderId"] };

    dataSet.Tables.AddRange(new DataTable[] { customersTable, ordersTable });

    // Check to see if each table can be removed and then 
    // remove it. 
    while (dataSet.Tables.Count > 0)
    {
        DataTable table = dataSet.Tables[0];
        if (dataSet.Tables.CanRemove(table))
        {
            dataSet.Tables.RemoveAt(0);
        }
    }

    Console.WriteLine("dataSet has {0} tables",
        dataSet.Tables.Count);
}

private static void Collection_Changing(object sender,
    System.ComponentModel.CollectionChangeEventArgs e)
{
    // Implementing this event allows you to abort a change 
    // to the collection by raising an exception which you can 
    // catch.

    Console.WriteLine("Collection_Changing Event: '{0}'\table element={1}",
        e.Action.ToString(), e.Element.ToString());
}

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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