Rows
DataRowCollection drc = DataTable.Rows;
Accesses the DataRowCollection for the
DataTable, providing access to the
DataRow objects belonging to the
DataTable. The Rows property
can be used to add, remove, and examine the
DataRow objects in a DataTable.
There are two methods that can add a row to a table. The
Add( ) method takes either a
DataRow argument or an object array of columns of
the row to be added:
DataTable dt = new DataTable("MyTable");
dt.Columns.Add("Column1", typeof(System.Int32));
dt.Columns.Add("Column2", typeof(System.String));
DataRow newRow = dt.NewRow();
newRow["Column1"] = 1;
newRow["Column2"] = "DataRow 1";
// add a row using a reference to a DataRow
dt.Rows.Add(newRow);
// add and create a DataRow in one statement
dt.Rows.Add(new Object[] {2, "DataRow 2"});A DataRow can also be inserted at a specific point
in the DataRowCollection using the
InsertAt( ) method, which in addition to a
reference to a DataRow, takes an argument
specifying the zero-based index at which to insert the row.
// create a new row
DataRow row = dt.NewRow();
row.ItemArray = new Object[] {1, "DataRow 1"};
// insert a new row as the first item of the collection
dt.Rows.InsertAt(row,0);The Contains( ) method returns a value that
indicates whether the primary key exists in the collection of rows.
The method has two overloads taking an object or an array of objects
allowing primary keys based on one or more columns to be examined.
// look for a primary key that is based on a single column
bool exists = dt.Rows.Contains("PK Value 1");
// look for a primary key that is based on multiple columns
bool exists = dt.Rows.Contains(new Object[] {"PK Field1 Value",
"PK Field2 Value"});The Find( ) method is the second method available
to locate a row based on the primary key. The Find( ) method differs from the Contains( )
method in that it returns the matching row rather than just
indicating if a matching row exists. Like the Contains( ) method, the Find( ) method has two
overloads taking an object or an array of objects allowing rows with
primary keys based on a single or multiple columns to be returned. A
null reference is returned if a matching row
isn’t found.
// get the row for a primary key that is based on a single column
DataRow row = dt.Rows.Find("PK Value 1");
// get the row for a primary key that is based on multiple columns
DataRow row = dt.Rows.Find(new Object[] {"PK Field1 Value",
"PK Field2 Value"});The Remove( ) method removes a row specified by a
DataRow argument from the collection:
// remove the row matching the primary key value, if found
DataRow row = dt.Rows.Find("PK Value 1");
if(row != null)
dt.Rows.Remove(row);The RemoveAt( ) method removes the row specified
by a zero-based index argument from the collection. If there no row
at the index, an IndexOutOfRangeException is
raised.
// remove the first row from the collection dt.Rows.RemoveAt(0);
The Clear( ) method removes all rows from the
collection:
// remove all rows from the table dt.Rows.Clear();
The DataRowCollection class derives its standard
functionality from the InternalDataCollectionBase
class from which it inherits.
The commonly used public properties of the
DataRowCollection are listed and described in
Table 23-11.
The commonly used public methods of the
DataRowCollection are listed and described in
Table 23-12.