в 15:31, 26 мая 2010

2010-05-26T15:31:19Z

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2010-05-26T11:42:20Z

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==Create DataView through DataTable==

<source lang="csharp">
using System;
using System.Data;
using System.Data.SqlClient;
class DataViewExample
{
static void Main()
{
string connString = "server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI";
string sql = @"select * from employee";
SqlConnection conn = new SqlConnection(connString);
try {
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = new SqlCommand(sql, conn);
DataSet ds = new DataSet();
da.Fill(ds, "employee");
DataTable dt = ds.Tables["employee"];
DataView dv = new DataView(dt,"lastname = "Z"", "lastname", DataViewRowState.CurrentRows);
foreach (DataRowView drv in dv)
{
for (int i = 0; i < dv.Table.Columns.Count; i++){
Console.Write(drv[i] + "\t");
}
}
}
catch(Exception e)
{
Console.WriteLine("Error: " + e);
}
finally
{
conn.Close();
}
}
}

</source>

==illustrates the use of a DataView object to filter and sort rows==

<source lang="csharp">
/*
Mastering Visual C# .NET
by Jason Price, Mike Gunderloy
Publisher: Sybex;
ISBN: 0782129110
*/
/*
Example23_5.cs illustrates the use of a DataView object to
filter and sort rows
*/
using System;
using System.Data;
using System.Data.SqlClient;
public class Example23_5
{
public static void Main()
{
// formulate a string containing the details of the
// database connection
string connectionString =
"server=localhost;database=Northwind;uid=sa;pwd=sa";
// create a SqlConnection object to connect to the
// database, passing the connection string to the constructor
SqlConnection mySqlConnection =
new SqlConnection(connectionString);
// formulate a string containing a SELECT statement
string selectString =
"SELECT CustomerID, CompanyName, City, Country " +
"FROM Customers";
// create a SqlCommand object to hold the SELECT statement
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
// set the CommandText property of the SqlCommand object to
// the SELECT string
mySqlCommand.rumandText = selectString;
// create a SqlDataAdapter object
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
// set the SelectCommand property of the SqlAdapter object
// to the SqlCommand object
mySqlDataAdapter.SelectCommand = mySqlCommand;
// create a DataSet object to store the results of
// the SELECT statement
DataSet myDataSet = new DataSet();
// open the database connection using the
// Open() method of the SqlConnection object
mySqlConnection.Open();
// use the Fill() method of the SqlDataAdapter object to
// retrieve the rows from the table, storing the rows locally
// in a DataTable of the DataSet object
Console.WriteLine("Retrieving rows from the Customers table");
mySqlDataAdapter.Fill(myDataSet, "Customers");
// create a DataView object
DataView myDataView =
new DataView(myDataSet.Tables["Customers"]);
// set the RowFilter property of the DataView object
myDataView.RowFilter = "Country = "UK"";
// set the Sort property of the DataView object
myDataView.Sort = "CustomerID ASC";
// display the rows in the DataView object
foreach (DataRowView myDataRowView in myDataView)
{
for (int count = 0; count < myDataView.Table.Columns.Count; count++)
{
Console.WriteLine(myDataRowView[count]);
}
}
// close the database connection using the Close() method
// of the SqlConnection object
mySqlConnection.Close();
}
}

</source>

==use the Find() and FindRows() methods of a DataView to find DataRowView objects==

<source lang="csharp">

using System;
using System.Data;
using System.Data.SqlClient;
class FindingDataRowViews {
public static void Main() {
SqlConnection mySqlConnection =
new SqlConnection(
"server=localhost;database=Northwind;uid=sa;pwd=sa"
);
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.rumandText =
"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"];
string filterExpression = "Country = "UK"";
string sortExpression = "CustomerID";
DataViewRowState rowStateFilter = DataViewRowState.OriginalRows;
DataView customersDV = new DataView();
customersDV.Table = customersDT;
customersDV.RowFilter = filterExpression;
customersDV.Sort = sortExpression;
customersDV.RowStateFilter = rowStateFilter;
foreach (DataRowView myDataRowView in customersDV) {
for (int count = 0; count < customersDV.Table.Columns.Count; count++) {
Console.WriteLine(myDataRowView[count]);
}
Console.WriteLine("");
}
int index = customersDV.Find("BSBEV");
Console.WriteLine("BSBEV found at index " + index + "\n");
DataRowView[] customersDRVs = customersDV.FindRows("BSBEV");
foreach (DataRowView myDataRowView in customersDRVs) {
for (int count = 0; count < customersDV.Table.Columns.Count; count++) {
Console.WriteLine(myDataRowView[count]);
}
Console.WriteLine("");
}
}
}

</source>

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в 15:31, 26 мая 2010

Admin: 1 версия