/* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110 */ /* Example23_3.cs illustrates the use of adding, modifying, and deleting a row in a DataTable object and synchronizing those changes with the database */ using System; using System.Data; using System.Data.SqlClient; public class Example23_3 { public static void DisplayDataTable(DataTable myDataTable) { // display the columns for each row in the DataTable, // using a DataRow object to access each row in the DataTable foreach (DataRow myDataRow in myDataTable.Rows) { Console.WriteLine("CustomerID = " + myDataRow["CustomerID"]); Console.WriteLine("CompanyName = " + myDataRow["CompanyName"]); Console.WriteLine("ContactName = " + myDataRow["ContactName"]); Console.WriteLine("Address = " + myDataRow["Address"]); } } public static void AddRow( DataTable myDataTable ) { Console.WriteLine(" Adding a new row with CustomerID of 'T1COM'"); // step 1: use the NewRow() method of the DataRow object to create // a new row in the DataTable DataRow myNewDataRow = myDataTable.NewRow(); // step 2: set the values for the columns of the new row myNewDataRow["CustomerID"] = "T1COM"; myNewDataRow["CompanyName"] = "T1 Company"; myNewDataRow["ContactName"] = "Jason Price"; myNewDataRow["Address"] = "1 Main Street"; // step 3: use the Add() method through the Rows property to add // the new DataRow to the DataTable myDataTable.Rows.Add(myNewDataRow); // step 4: use the AcceptChanges() method of the DataTable to commit // the changes myDataTable.AcceptChanges(); } public static void ModifyRow( DataTable myDataTable ) { Console.WriteLine(" Modifying the new row"); // step 1: set the PrimaryKey property for the DataTable object DataColumn[] myPrimaryKey = new DataColumn[1]; myPrimaryKey[0] = myDataTable.Columns["CustomerID"]; myDataTable.PrimaryKey = myPrimaryKey; // step 2: use the Find() method to locate the DataRow // in the DataTable using the primary key value DataRow myEditDataRow = myDataTable.Rows.Find("T1COM"); // step 3: change the column values myEditDataRow["CompanyName"] = "Widgets Inc."; myEditDataRow["ContactName"] = "John Smith"; myEditDataRow["Address"] = "1 Any Street"; // step 4: use the AcceptChanges() method of the DataTable to commit // the changes myDataTable.AcceptChanges(); Console.WriteLine("myEditDataRow.RowState = " + myEditDataRow.RowState); } public static void RemoveRow( DataTable myDataTable ) { Console.WriteLine(" Removing the new row"); // step 1: set the PrimaryKey property for the DataTable object DataColumn[] myPrimaryKey = new DataColumn[1]; myPrimaryKey[0] = myDataTable.Columns["CustomerID"]; myDataTable.PrimaryKey = myPrimaryKey; // step 2: use the Find() method to locate the DataRow DataRow myRemoveDataRow = myDataTable.Rows.Find("T1COM"); // step 3: use the Delete() method to remove the DataRow myRemoveDataRow.Delete(); // step 4: use the AcceptChanges() method of the DataTable to commit // the changes myDataTable.AcceptChanges(); } 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 SELECT statement to retrieve the // CustomerID, CompanyName, ContactName, and Address // columns for the first row from the Customers table string selectString = "SELECT CustomerID, CompanyName, ContactName, Address " + "FROM Customers " + "WHERE CustomerID = 'ALFKI'"; // 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.CommandText = 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 a row from the Customers table"); mySqlDataAdapter.Fill(myDataSet, "Customers"); // get the DataTable object from the DataSet object DataTable myDataTable = myDataSet.Tables["Customers"]; // display the rows in the DataTable object DisplayDataTable(myDataTable); // add a new row AddRow(myDataTable); DisplayDataTable(myDataTable); // modify a row ModifyRow(myDataTable); DisplayDataTable(myDataTable); // remove a row RemoveRow(myDataTable); DisplayDataTable(myDataTable); // use the Fill() method of the SqlDataAdapter object // to synchronize the changes with the database mySqlDataAdapter.Fill(myDataSet, "Customers"); // close the database connection using the Close() method // of the SqlConnection object mySqlConnection.Close(); } }
Database ADO.net
Print DataTable
using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
class Program {
static void Main(string[] args) {
DataSet carsInventoryDS = new DataSet(“Inventory”);
carsInventoryDS.ExtendedProperties[“TimeStamp”] = DateTime.Now;
carsInventoryDS.ExtendedProperties[“Company”] = “Name”;
DataColumn carIDColumn = new DataColumn(“CarID”, typeof(int));
carIDColumn.ReadOnly = true;
carIDColumn.Caption = “Car ID”;
carIDColumn.AllowDBNull = false;
carIDColumn.Unique = true;
carIDColumn.AutoIncrement = true;
carIDColumn.AutoIncrementSeed = 0;
carIDColumn.AutoIncrementStep = 1;
carIDColumn.ColumnMapping = MappingType.Attribute;
DataColumn carMakeColumn = new DataColumn(“Make”, typeof(string));
DataColumn carColorColumn = new DataColumn(“Color”, typeof(string));
DataColumn carPetNameColumn = new DataColumn(“PetName”, typeof(string));
carPetNameColumn.Caption = “Name”;
DataTable inventoryTable = new DataTable(“Inventory”);
inventoryTable.Columns.AddRange(new DataColumn[] { carIDColumn, carMakeColumn, carColorColumn, carPetNameColumn });
inventoryTable.PrimaryKey = new DataColumn[] { inventoryTable.Columns[0] };
DataRow carRow = inventoryTable.NewRow();
carRow[“Make”] = “B”;
carRow[“Color”] = “C”;
carRow[“PetName”] = “A”;
inventoryTable.Rows.Add(carRow);
carRow = inventoryTable.NewRow();
carRow[“Make”] = “S”;
carRow[“Color”] = “R”;
carRow[“PetName”] = “E”;
inventoryTable.Rows.Add(carRow);
carsInventoryDS.Tables.Add(inventoryTable);
PrintTable(carsInventoryDS.Tables[“Inventory”]);
}
private static void PrintTable(DataTable dt) {
DataTableReader dtReader = dt.CreateDataReader();
while (dtReader.Read()) {
for (int i = 0; i < dtReader.FieldCount; i++) {
Console.Write("{0} = {1} ",
dtReader.GetName(i).Trim(),
dtReader.GetValue(i).ToString().Trim());
}
Console.WriteLine();
}
dtReader.Close();
}
}
[/csharp]
Use DataViewManager to wrap DataSet
using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; using System.Configuration; using System.Data.SqlClient; public class Form1 : Form { public Form1() { InitializeComponent(); } private void getData_Click(object sender, EventArgs e) { string orders = "SELECT * FROM Orders"; string customers = "SELECT * FROM Customers"; using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["northwind"].ConnectionString)) { SqlDataAdapter da = new SqlDataAdapter(orders, con); DataSet ds = new DataSet(); da.Fill(ds, "Orders"); da = new SqlDataAdapter(customers, con); da.Fill(ds, "Customers"); ds.Relations.Add("CustomerOrders", ds.Tables["Customers"].Columns["CustomerID"], ds.Tables["Orders"].Columns["CustomerID"]); DataViewManager dvm = new DataViewManager(ds); dvm.DataViewSettings["Customers"].RowFilter = "Country='UK'"; dataGrid1.SetDataBinding(dvm, "Customers"); } } private void InitializeComponent() { this.dataGrid1 = new System.Windows.Forms.DataGrid(); this.getData = new System.Windows.Forms.Button(); ((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).BeginInit(); this.SuspendLayout(); this.dataGrid1.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom) | System.Windows.Forms.AnchorStyles.Left) | System.Windows.Forms.AnchorStyles.Right))); this.dataGrid1.DataMember = ""; this.dataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText; this.dataGrid1.Location = new System.Drawing.Point(13, 13); this.dataGrid1.Size = new System.Drawing.Size(488, 374); this.getData.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right))); this.getData.Location = new System.Drawing.Point(426, 393); this.getData.Size = new System.Drawing.Size(75, 23); this.getData.Text = "Get Data"; this.getData.UseVisualStyleBackColor = true; this.getData.Click += new System.EventHandler(this.getData_Click); this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(513, 428); this.Controls.Add(this.getData); this.Controls.Add(this.dataGrid1); ((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).EndInit(); this.ResumeLayout(false); } private System.Windows.Forms.DataGrid dataGrid1; private System.Windows.Forms.Button getData; [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } }
Populate a DataSet object with multiple DataTable objects by changing the CommandText property of a DataAdapter object's SelectCommand
using System; using System.Data; using System.Data.SqlClient; class MultipleDataTables2 { public static void Main() { SqlConnection mySqlConnection = new SqlConnection("server=localhost;database=Northwind;uid=sa;pwd=sa"); SqlCommand mySqlCommand = mySqlConnection.CreateCommand(); mySqlCommand.CommandText = "SELECT TOP 2 ProductID, ProductName, UnitPrice FROM Products ORDER BY ProductID"; SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter(); mySqlDataAdapter.SelectCommand = mySqlCommand; DataSet myDataSet = new DataSet(); mySqlConnection.Open(); int numberOfRows = mySqlDataAdapter.Fill(myDataSet, "Products"); Console.WriteLine("numberOfRows = " + numberOfRows); mySqlDataAdapter.SelectCommand.CommandText = "SELECT CustomerID, CompanyName FROM Customers WHERE CustomerID = 'ALFKI'"; numberOfRows = mySqlDataAdapter.Fill(myDataSet, "Customers"); Console.WriteLine("numberOfRows = " + numberOfRows); mySqlConnection.Close(); foreach (DataTable myDataTable in myDataSet.Tables) { Console.WriteLine(" Reading from the " + myDataTable.TableName + " DataTable"); foreach (DataRow myDataRow in myDataTable.Rows) { foreach (DataColumn myDataColumn in myDataTable.Columns) { Console.WriteLine(myDataColumn + " = " + myDataRow[myDataColumn]); } } } } }
Read data from DataSet
using System; using System.Data; using System.Data.SqlClient; class PopDataset { static void Main() { string connString = "server=(local)SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI"; string sql = @"select * from employee"; SqlConnection conn = new SqlConnection(connString); try { conn.Open(); SqlDataAdapter da = new SqlDataAdapter(sql, conn); DataSet ds = new DataSet(); da.Fill(ds, "employee"); DataTable dt = ds.Tables["employee"]; foreach (DataRow row in dt.Rows) { foreach (DataColumn col in dt.Columns) Console.WriteLine(row[col]); Console.WriteLine("".PadLeft(20, '=')); } } catch(Exception e) { Console.WriteLine("Error: " + e); } finally { conn.Close(); } } }
Using Multi Tabled Datasets
/* * C# Programmers Pocket Consultant * Author: Gregory S. MacBeth * Email: gmacbeth@comporium.net * Create Date: June 27, 2003 * Last Modified Date: * Version: 1 */ using System; using System.Data; using System.Data.OleDb; namespace Client.Chapter_13___ADO.NET { public class UsingMultiTabledDatasets { static void Main(string[] args) { OleDbConnection MyConnection = new OleDbConnection(@"Provider=Microsft.Jet.OLEDB.4.0; Data Source = c:MyAccessDB.mdb"); OleDbDataAdapter MyAdapter = new OleDbDataAdapter("SELECT Column1, Column2, Column3 FROM MyTable", MyConnection); DataSet MyDataSet = new DataSet(); MyAdapter.Fill(MyDataSet, "MyTable"); foreach (DataTable MyTable in MyDataSet.Tables) { foreach (DataColumn MyColumn in MyTable.Columns) { foreach (DataRow MyRow in MyTable.Rows) { } } } } } }
Using Datasets
/* * C# Programmers Pocket Consultant * Author: Gregory S. MacBeth * Email: gmacbeth@comporium.net * Create Date: June 27, 2003 * Last Modified Date: * Version: 1 */ using System; using System.Data; using System.Data.SqlClient; namespace Client.Chapter_13___ADO.NET { public class UsingDatasets { static void Main(string[] args) { SqlConnection MyConnection = new SqlConnection(@"Data Source=(local); Initial Catalog = CaseManager; Integrated Security=true"); SqlDataAdapter MyAdapter = new SqlDataAdapter("SELECT * FROM CaseInfo", MyConnection); DataSet MyDataSet = new DataSet(); MyAdapter.Fill(MyDataSet, "MyTable"); MyDataSet.WriteXml(@"c:MyDatSet.xml"); } } }