Creating and Using a DataViewManager Object

To create a DataViewManager, you use one of the following constructors:

 DataViewManager() DataViewManager(DataSet myDataSet)

where myDataSet specifies the DataSet used by the DataViewManager object. This sets the DataSet property of the new DataViewManager object to myDataSet.

Let's take a look at an example of creating and using a DataViewManager. Assume you have a DataSet named myDataSet, which contains a DataTable populated with rows from the Customers table. The following example creates a DataViewManager object named myDVM, passing myDataSet to the constructor:

 DataViewManager myDVM = new DataViewManager(myDataSet);

The next example sets the Sort and RowFilter properties that will be used later when a DataView for the Customers DataTable is created:

 myDVM.DataViewSettings["Customers"].Sort = "CustomerID"; myDVM.DataViewSettings["Customers"].RowFilter = "Country = 'UK'";

Note

The previous code doesn't actually create a DataView; it merely sets the properties of any DataView created in the future that views rows from the Customers DataTable.

The following example actually creates a DataView by calling the CreateDataView() method of the myDVM DataViewManager, passing the customersDT DataTable to CreateDataView():

 DataView customersDV = myDVM.CreateDataView(customersDT);

The Sort and RowFilter properties of the customersDV DataView are set to CustomerID and Country = 'UK' respectively. These are the same settings as those set earlier in the DataViewSettings property.

Listing 13.4A shows a complete example that creates and uses the DataViewManager shown in this section.

Listing 13.4A: USINGDATAVIEWMANAGER.CS

 /* UsingDataViewManager.cs illustrates the use of a DataViewManager object */ using System; using System.Data; using System.Data.SqlClient; class UsingDataViewManager {   public static void Main()   {     SqlConnection mySqlConnection =       new SqlConnection(         "server=localhost;database=Northwind;uid=sa;pwd=sa"       );     SqlCommand mySqlCommand = mySqlConnection.CreateCommand();     mySqlCommand.CommandText =       "SELECT CustomerID, CompanyName, Country " +       "FROM Customers";     SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();     mySqlDataAdapter.SelectCommand = mySqlCommand;     DataSet myDataSet = new DataSet();     mySqlConnection.Open();     mySqlDataAdapter.Fill(myDataSet, "Customers");     mySqlConnection.Close();     DataTable customersDT = myDataSet.Tables["Customers"];     // create a DataViewManager object named myDVM     DataViewManager myDVM = new DataViewManager(myDataSet);     // set the Sort and RowFilter properties for the Customers DataTable     myDVM.DataViewSettings["Customers"].Sort = "CustomerID";     myDVM.DataViewSettings["Customers"].RowFilter = "Country = 'UK'";     // display the DataViewSettingCollectionString property of myDVM     Console.WriteLine("myDVM.DataViewSettingCollectionString = " +       myDVM.DataViewSettingCollectionString + "\n");     // call the CreateDataView() method of myDVM to create a DataView     // named customersDV for the customersDT DataTable     DataView customersDV = myDVM.CreateDataView(customersDT);     // display the rows in the customersDV DataView object     foreach (DataRowView myDataRowView in customersDV)     {       for (int count = 0; count < customersDV.Table.Columns.Count; count++)       {         Console.WriteLine(myDataRowView[count]);       }       Console.WriteLine("");     }   } }

The output from this program is as follows:

 myDVM.DataViewSettingCollectionString =  <DataViewSettingCollectionString>  <Customers Sort="CustomerID" RowFilter="Country = 'UK'" RowStateFilter="CurrentRows"/>  </DataViewSettingCollectionString> AROUT Around the Horn UK BSBEV B's Beverages UK CONSH Consolidated Holdings UK EASTC Eastern Connection UK ISLAT Island Trading UK NORTS North/South UK SEVES Seven Seas Imports UK