如何：将 Windows 窗体控件绑定到 Factory 对象
更新：2007 年 11 月
生成与数据交互的控件时，有时会觉得有必要将控件绑定到生成其他对象的对象或方法。这样的对象或方法称为一个工厂。例如，数据源可能是来自某个方法调用的返回值，而不是内存中的一个对象或一个类型。只要此类数据源返回一个集合，就可以将控件绑定到此数据源。
通过使用 BindingSource 控件，您可以很容易地将控件绑定到某个工厂对象。
示例
下面的示例演示如何通过使用 BindingSource 控件将 DataGridView 控件绑定到一个工厂方法。此工厂方法命名为 GetOrdersByCustomerId，它返回 Northwind 数据库中某个给定客户的所有订单。
Imports System
Imports System.Collections
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Data.Common
Imports System.Diagnostics
Imports System.Drawing
Imports System.Data.SqlClient
Imports System.Windows.Forms
' This form demonstrates using a BindingSource to bind to a factory
' object.
Public Class Form1
Inherits System.Windows.Forms.Form
' This is the TextBox for entering CustomerID values.
Private WithEvents customerIdTextBox As New TextBox()
' This is the DataGridView that displays orders for the
' specified customer.
Private customersDataGridView As New DataGridView()
' This is the BindingSource for binding the database query
' result set to the DataGridView.
Private ordersBindingSource As New BindingSource()
Public Sub New()
' Set up the CustomerID TextBox.
Me.customerIdTextBox.Location = New Point(100, 200)
Me.customerIdTextBox.Size = New Size(500, 30)
Me.customerIdTextBox.Text = _
"Enter a valid Northwind CustomerID, for example: ALFKI," & _
" then RETURN or click outside the TextBox"
Me.Controls.Add(Me.customerIdTextBox)
' Set up the DataGridView.
customersDataGridView.Dock = DockStyle.Top
Me.Controls.Add(customersDataGridView)
' Set up the form.
Me.Size = New Size(800, 500)
End Sub
' This event handler binds the BindingSource to the DataGridView
' control's DataSource property.
Private Sub Form1_Load(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Me.Load
' Attach the BindingSource to the DataGridView.
Me.customersDataGridView.DataSource = Me.ordersBindingSource
End Sub
' This is a static factory method. It queries the Northwind
' database for the orders belonging to the specified
' customer and returns an IEnumerable.
Public Shared Function GetOrdersByCustomerId(ByVal id As String) _
As IEnumerable
' Open a connection to the database.
Dim connectString As String = "Integrated Security=SSPI;" & _
"Persist Security Info=False;Initial Catalog=Northwind;" & _
"Data Source= localhost"
Dim connection As New SqlConnection()
connection.ConnectionString = connectString
connection.Open()
' Execute the query.
Dim queryString As String = _
String.Format("Select * From Orders where CustomerID = '{0}'", id)
Dim command As New SqlCommand(queryString, connection)
Dim reader As SqlDataReader = _
command.ExecuteReader(CommandBehavior.CloseConnection)
Return reader
End Function
' These event handlers are called when the user tabs or clicks
' out of the customerIdTextBox or hits the return key.
' The database is then queried with the CustomerID
' in the customerIdTextBox.Text property.
Private Sub customerIdTextBox_Leave(ByVal sender As Object, _
ByVal e As EventArgs) Handles customerIdTextBox.Leave
' Attach the data source to the BindingSource control.
Me.ordersBindingSource.DataSource = _
GetOrdersByCustomerId(Me.customerIdTextBox.Text)
End Sub
Private Sub customerIdTextBox_KeyDown(ByVal sender As Object, _
ByVal e As KeyEventArgs) Handles customerIdTextBox.KeyDown
If e.KeyCode = Keys.Return Then
' Attach the data source to the BindingSource control.
Me.ordersBindingSource.DataSource = _
GetOrdersByCustomerId(Me.customerIdTextBox.Text)
End If
End Sub
<STAThread()> _
Shared Sub Main()
Application.EnableVisualStyles()
Application.Run(New Form1())
End Sub
End Class
using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.Common;
using System.Diagnostics;
using System.Drawing;
using System.Data.SqlClient;
using System.Windows.Forms;
// This form demonstrates using a BindingSource to bind to a factory
// object.
public class Form1 : System.Windows.Forms.Form
{
// This is the TextBox for entering CustomerID values.
private TextBox customerIdTextBox = new TextBox();
// This is the DataGridView that displays orders for the
// specified customer.
private DataGridView customersDataGridView = new DataGridView();
// This is the BindingSource for binding the database query
// result set to the DataGridView.
private BindingSource ordersBindingSource = new BindingSource();
public Form1()
{
// Set up the CustomerID TextBox.
this.customerIdTextBox.Location = new Point(100, 200);
this.customerIdTextBox.Size = new Size(500, 30);
this.customerIdTextBox.Text =
"Enter a valid Northwind CustomerID, for example: ALFKI," +
" then RETURN or click outside the TextBox";
this.customerIdTextBox.Leave +=
new EventHandler(customerIdTextBox_Leave);
this.customerIdTextBox.KeyDown +=
new KeyEventHandler(customerIdTextBox_KeyDown);
this.Controls.Add(this.customerIdTextBox);
// Set up the DataGridView.
customersDataGridView.Dock = DockStyle.Top;
this.Controls.Add(customersDataGridView);
// Set up the form.
this.Size = new Size(800, 500);
this.Load += new EventHandler(Form1_Load);
}
// This event handler binds the BindingSource to the DataGridView
// control's DataSource property.
private void Form1_Load(
System.Object sender,
System.EventArgs e)
{
// Attach the BindingSource to the DataGridView.
this.customersDataGridView.DataSource =
this.ordersBindingSource;
}
// This is a static factory method. It queries the Northwind
// database for the orders belonging to the specified
// customer and returns an IEnumerable.
public static IEnumerable GetOrdersByCustomerId(string id)
{
// Open a connection to the database.
string connectString = "Integrated Security=SSPI;" +
"Persist Security Info=False;Initial Catalog=Northwind;" +
"Data Source= localhost";
SqlConnection connection = new SqlConnection();
connection.ConnectionString = connectString;
connection.Open();
// Execute the query.
string queryString =
String.Format("Select * From Orders where CustomerID = '{0}'",
id);
SqlCommand command = new SqlCommand(queryString, connection);
SqlDataReader reader =
command.ExecuteReader(CommandBehavior.CloseConnection);
return reader;
}
// These event handlers are called when the user tabs or clicks
// out of the customerIdTextBox or hits the return key.
// The database is then queried with the CustomerID
// in the customerIdTextBox.Text property.
void customerIdTextBox_Leave(object sender, EventArgs e)
{
// Attach the data source to the BindingSource control.
this.ordersBindingSource.DataSource =
GetOrdersByCustomerId(this.customerIdTextBox.Text);
}
void customerIdTextBox_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Return)
{
// Attach the data source to the BindingSource control.
this.ordersBindingSource.DataSource =
GetOrdersByCustomerId(this.customerIdTextBox.Text);
}
}
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.Run(new Form1());
}
}
#using <System.dll>
#using <System.Data.dll>
#using <System.Drawing.dll>
#using <System.EnterpriseServices.dll>
#using <System.Transactions.dll>
#using <System.Windows.Forms.dll>
#using <System.Xml.dll>
using namespace System;
using namespace System::Collections;
using namespace System::Collections::Generic;
using namespace System::ComponentModel;
using namespace System::Data;
using namespace System::Data::Common;
using namespace System::Data::SqlClient;
using namespace System::Diagnostics;
using namespace System::Drawing;
using namespace System::Windows::Forms;
// This form demonstrates using a BindingSource to bind to a factory
// object.
public ref class Form1: public System::Windows::Forms::Form
{
private:
// This is the TextBox for entering CustomerID values.
static TextBox^ customerIdTextBox = gcnew TextBox;
// This is the DataGridView that displays orders for the
// specified customer.
static DataGridView^ customersDataGridView = gcnew DataGridView;
// This is the BindingSource for binding the database query
// result set to the DataGridView.
static BindingSource^ ordersBindingSource = gcnew BindingSource;
public:
Form1()
{
// Set up the CustomerID TextBox.
this->customerIdTextBox->Dock = DockStyle::Bottom;
this->customerIdTextBox->Text =
L"Enter a valid Northwind CustomerID, for example: ALFKI,"
L" then TAB or click outside the TextBox";
this->customerIdTextBox->Leave += gcnew EventHandler(
this, &Form1::customerIdTextBox_Leave );
this->Controls->Add( this->customerIdTextBox );
// Set up the DataGridView.
customersDataGridView->Dock = DockStyle::Top;
this->Controls->Add( customersDataGridView );
// Set up the form.
this->Size = System::Drawing::Size( 800, 800 );
this->Load += gcnew EventHandler( this, &Form1::Form1_Load );
}
private:
// This event handler binds the BindingSource to the DataGridView
// control's DataSource property.
void Form1_Load(
System::Object^ /*sender*/,
System::EventArgs^ /*e*/ )
{
// Attach the BindingSource to the DataGridView.
this->customersDataGridView->DataSource =
this->ordersBindingSource;
}
public:
// This is a static factory method. It queries the Northwind
// database for the orders belonging to the specified
// customer and returns an IList.
static System::Collections::IList^ GetOrdersByCustomerId( String^ id )
{
// Open a connection to the database.
String^ connectString = L"Integrated Security=SSPI;"
L"Persist Security Info=False;Initial Catalog=Northwind;"
L"Data Source= localhost";
SqlConnection^ connection = gcnew SqlConnection;
connection->ConnectionString = connectString;
connection->Open();
// Execute the query.
String^ queryString = String::Format(
L"Select * From Orders where CustomerID = '{0}'", id );
SqlCommand^ command = gcnew SqlCommand( queryString,connection );
SqlDataReader^ reader = command->ExecuteReader(
CommandBehavior::CloseConnection );
// Build an IList from the result set.
List< DbDataRecord^ >^ list = gcnew List< DbDataRecord^ >;
System::Collections::IEnumerator^ e = reader->GetEnumerator();
while ( e->MoveNext() )
{
list->Add( dynamic_cast<DbDataRecord^>(e->Current) );
}
return list;
}
// This event handler is called when the user tabs or clicks
// out of the customerIdTextBox. The database is then queried
// with the CustomerID in the customerIdTextBox.Text property.
private:
void customerIdTextBox_Leave( Object^ /*sender*/, EventArgs^ /*e*/ )
{
// Attach the data source to the BindingSource control.
this->ordersBindingSource->DataSource = GetOrdersByCustomerId(
this->customerIdTextBox->Text );
}
public:
[STAThread]
static void main()
{
Application::EnableVisualStyles();
Application::Run( gcnew Form1 );
}
};
编译代码
此示例要求：
- 对 System、System.Data、System.Drawing 和 System.Windows.Forms 程序集的引用。
有关从 Visual Basic 或 Visual C# 的命令行生成此示例的信息，请参见从命令行生成 (Visual Basic) 或在命令行上使用 csc.exe 生成。也可以通过将代码粘贴到新项目，在 Visual Studio 中生成此示例。 如何：使用 Visual Studio 编译和运行完整的 Windows 窗体代码示例
如何：使用 Visual Studio 编译和运行完整的 Windows 窗体代码示例
如何：使用 Visual Studio 编译和运行完整的 Windows 窗体代码示例
如何：使用 Visual Studio 编译和运行完整的 Windows 窗体代码示例
如何：使用 Visual Studio 编译和运行完整的 Windows 窗体代码示例