Porady: dostosowywanie dodawania elementu przy użyciu kontrolki BindingSource formularzy systemu Windows
Jeśli używasz BindingSource składnika do powiązania kontrolki Windows Forms ze źródłem danych, może być konieczne dostosowanie tworzenia nowych elementów. Składnik BindingSource sprawia, że jest to proste, dostarczając AddingNew zdarzenie, które jest zwykle wywoływane, gdy powiązana kontrolka musi utworzyć nowy element. Program obsługi zdarzeń może zapewnić dowolne zachowanie niestandardowe (na przykład wywołanie metody w usłudze internetowej lub pobranie nowego obiektu z fabryki klas).
Uwaga
Po dodaniu elementu przez obsługę AddingNew zdarzenia nie można anulować dodawania.
Przykład
W poniższym przykładzie pokazano, jak powiązać kontrolkę z fabryką DataGridView klas przy użyciu BindingSource składnika. Gdy użytkownik kliknie nowy wiersz kontrolki DataGridView , zostanie AddingNew zgłoszone zdarzenie. Procedura obsługi zdarzeń tworzy nowy DemoCustomer obiekt, który jest przypisany do AddingNewEventArgs.NewObject właściwości . Powoduje to dodanie nowego DemoCustomer obiektu do BindingSource listy składnika i wyświetlenie go w nowym wierszu kontrolki DataGridView .
#using <System.dll>
#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>
using namespace System;
using namespace System::ComponentModel;
using namespace System::Drawing;
using namespace System::Globalization;
using namespace System::Windows::Forms;
namespace DataConnectorAddingNewExample
{
// This class implements a simple customer type.
public ref class DemoCustomer
{
private:
// These fields hold the values for the public properties.
Guid idValue;
String^ customerName;
String^ companyNameValue;
String^ phoneNumberValue;
// The constructor is private to enforce the factory pattern.
DemoCustomer()
{
idValue = Guid::NewGuid();
customerName = String::Empty;
companyNameValue = String::Empty;
phoneNumberValue = String::Empty;
customerName = "no data";
companyNameValue = "no data";
phoneNumberValue = "no data";
}
public:
// This is the public factory method.
static DemoCustomer^ CreateNewCustomer()
{
return gcnew DemoCustomer;
}
property Guid ID
{
// This property represents an ID, suitable
// for use as a primary key in a database.
Guid get()
{
return this->idValue;
}
}
property String^ CompanyName
{
String^ get()
{
return this->companyNameValue;
}
void set(String^ value)
{
this->companyNameValue = value;
}
}
property String^ PhoneNumber
{
String^ get()
{
return this->phoneNumberValue;
}
void set(String^ value)
{
this->phoneNumberValue = value;
}
}
};
// This form demonstrates using a BindingSource to provide
// data from a collection of custom types
// to a DataGridView control.
public ref class MainForm: public System::Windows::Forms::Form
{
private:
// This is the BindingSource that will provide data for
// the DataGridView control.
BindingSource^ customersBindingSource;
// This is the DataGridView control
// that will display our data.
DataGridView^ customersDataGridView;
// Set up the StatusBar for displaying ListChanged events.
StatusBar^ status;
public:
MainForm()
{
customersBindingSource = gcnew BindingSource;
customersDataGridView = gcnew DataGridView;
status = gcnew StatusBar;
// Set up the form.
this->Size = System::Drawing::Size(600, 400);
this->Text = "BindingSource.AddingNew sample";
this->Load +=
gcnew EventHandler(this, &MainForm::OnMainFormLoad);
this->Controls->Add(status);
// Set up the DataGridView control.
this->customersDataGridView->Dock = DockStyle::Fill;
this->Controls->Add(this->customersDataGridView);
// Attach an event handler for the AddingNew event.
this->customersBindingSource->AddingNew +=
gcnew AddingNewEventHandler(this,
&MainForm::OnCustomersBindingSourceAddingNew);
// Attach an event handler for the ListChanged event.
this->customersBindingSource->ListChanged +=
gcnew ListChangedEventHandler(this,
&MainForm::OnCustomersBindingSourceListChanged);
}
private:
void OnMainFormLoad(Object^ sender, EventArgs^ e)
{
// Add a DemoCustomer to cause a row to be displayed.
this->customersBindingSource->AddNew();
// Bind the BindingSource to the DataGridView
// control's DataSource.
this->customersDataGridView->DataSource =
this->customersBindingSource;
}
// This event handler provides custom item-creation behavior.
void OnCustomersBindingSourceAddingNew(Object^ sender,
AddingNewEventArgs^ e)
{
e->NewObject = DemoCustomer::CreateNewCustomer();
}
// This event handler detects changes in the BindingSource
// list or changes to items within the list.
void OnCustomersBindingSourceListChanged(Object^ sender,
ListChangedEventArgs^ e)
{
status->Text = Convert::ToString(e->ListChangedType,
CultureInfo::CurrentCulture);
}
};
}
[STAThread]
int main()
{
Application::EnableVisualStyles();
Application::Run(gcnew DataConnectorAddingNewExample::MainForm);
}
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Data.SqlClient;
using System.Windows.Forms;
// This form demonstrates using a BindingSource to provide
// data from a collection of custom types to a DataGridView control.
public class Form1 : System.Windows.Forms.Form
{
// This is the BindingSource that will provide data for
// the DataGridView control.
private BindingSource customersBindingSource = new BindingSource();
// This is the DataGridView control that will display our data.
private DataGridView customersDataGridView = new DataGridView();
// Set up the StatusBar for displaying ListChanged events.
private StatusBar status = new StatusBar();
public Form1()
{
// Set up the form.
this.Size = new Size(800, 800);
this.Load += new EventHandler(Form1_Load);
this.Controls.Add(status);
// Set up the DataGridView control.
this.customersDataGridView.Dock = DockStyle.Fill;
this.Controls.Add(customersDataGridView);
// Attach an event handler for the AddingNew event.
this.customersBindingSource.AddingNew +=
new AddingNewEventHandler(customersBindingSource_AddingNew);
// Attach an event handler for the ListChanged event.
this.customersBindingSource.ListChanged +=
new ListChangedEventHandler(customersBindingSource_ListChanged);
}
private void Form1_Load(System.Object sender, System.EventArgs e)
{
// Add a DemoCustomer to cause a row to be displayed.
this.customersBindingSource.AddNew();
// Bind the BindingSource to the DataGridView
// control's DataSource.
this.customersDataGridView.DataSource =
this.customersBindingSource;
}
// This event handler provides custom item-creation behavior.
void customersBindingSource_AddingNew(
object sender,
AddingNewEventArgs e)
{
e.NewObject = DemoCustomer.CreateNewCustomer();
}
// This event handler detects changes in the BindingSource
// list or changes to items within the list.
void customersBindingSource_ListChanged(
object sender,
ListChangedEventArgs e)
{
status.Text = e.ListChangedType.ToString();
}
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.Run(new Form1());
}
}
// This class implements a simple customer type.
public class DemoCustomer
{
// These fields hold the values for the public properties.
private Guid idValue = Guid.NewGuid();
private string customerName = String.Empty;
private string companyNameValue = String.Empty;
private string phoneNumberValue = String.Empty;
// The constructor is private to enforce the factory pattern.
private DemoCustomer()
{
customerName = "no data";
companyNameValue = "no data";
phoneNumberValue = "no data";
}
// This is the public factory method.
public static DemoCustomer CreateNewCustomer()
{
return new DemoCustomer();
}
// This property represents an ID, suitable
// for use as a primary key in a database.
public Guid ID
{
get
{
return this.idValue;
}
}
public string CompanyName
{
get
{
return this.companyNameValue;
}
set
{
this.companyNameValue = value;
}
}
public string PhoneNumber
{
get
{
return this.phoneNumberValue;
}
set
{
this.phoneNumberValue = value;
}
}
}
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Data.SqlClient
Imports System.Windows.Forms
' This form demonstrates using a BindingSource to provide
' data from a collection of custom types to a DataGridView control.
Public Class Form1
Inherits System.Windows.Forms.Form
' This is the BindingSource that will provide data for
' the DataGridView control.
Private WithEvents customersBindingSource As New BindingSource()
' This is the DataGridView control that will display our data.
Private customersDataGridView As New DataGridView()
' Set up the StatusBar for displaying ListChanged events.
Private status As New StatusBar()
Public Sub New()
' Set up the form.
Me.Size = New Size(800, 800)
AddHandler Me.Load, AddressOf Form1_Load
Me.Controls.Add(status)
' Set up the DataGridView control.
Me.customersDataGridView.Dock = DockStyle.Fill
Me.Controls.Add(customersDataGridView)
End Sub
Private Sub Form1_Load( _
ByVal sender As System.Object, _
ByVal e As System.EventArgs)
' Add a DemoCustomer to cause a row to be displayed.
Me.customersBindingSource.AddNew()
' Bind the BindingSource to the DataGridView
' control's DataSource.
Me.customersDataGridView.DataSource = Me.customersBindingSource
End Sub
' This event handler provides custom item-creation behavior.
Private Sub customersBindingSource_AddingNew( _
ByVal sender As Object, _
ByVal e As AddingNewEventArgs) _
Handles customersBindingSource.AddingNew
e.NewObject = DemoCustomer.CreateNewCustomer()
End Sub
' This event handler detects changes in the BindingSource
' list or changes to items within the list.
Private Sub customersBindingSource_ListChanged( _
ByVal sender As Object, _
ByVal e As ListChangedEventArgs) _
Handles customersBindingSource.ListChanged
status.Text = e.ListChangedType.ToString()
End Sub
<STAThread()> _
Shared Sub Main()
Application.EnableVisualStyles()
Application.Run(New Form1())
End Sub
End Class
' This class implements a simple customer type.
Public Class DemoCustomer
' These fields hold the values for the public properties.
Private idValue As Guid = Guid.NewGuid()
Private customerName As String = String.Empty
Private companyNameValue As String = String.Empty
Private phoneNumberValue As String = String.Empty
' The constructor is private to enforce the factory pattern.
Private Sub New()
customerName = "no data"
companyNameValue = "no data"
phoneNumberValue = "no data"
End Sub
' This is the public factory method.
Public Shared Function CreateNewCustomer() As DemoCustomer
Return New DemoCustomer()
End Function
' This property represents an ID, suitable
' for use as a primary key in a database.
Public ReadOnly Property ID() As Guid
Get
Return Me.idValue
End Get
End Property
Public Property CompanyName() As String
Get
Return Me.companyNameValue
End Get
Set(ByVal value As String)
Me.companyNameValue = Value
End Set
End Property
Public Property PhoneNumber() As String
Get
Return Me.phoneNumberValue
End Get
Set(ByVal value As String)
Me.phoneNumberValue = Value
End Set
End Property
End Class
Kompilowanie kodu
Ten przykład wymaga:
- Odwołania do zestawów System, System.Data, System.Drawing i System.Windows.Forms.
Zobacz też
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