Procedura: applicare il modello PropertyNameChanged
Aggiornamento: novembre 2007
Nell'esempio di codice seguente viene illustrato come applicare il modello NomeProprietàChanged a un controllo personalizzato. Applicare questo modello quando si implementano i controlli personalizzati utilizzati con il modulo di associazione dati di Windows Form.
Esempio
' This class implements a simple user control
' that demonstrates how to apply the propertyNameChanged pattern.
<ComplexBindingProperties("DataSource", "DataMember")> _
Public Class CustomerControl
Inherits UserControl
Private dataGridView1 As DataGridView
Private label1 As Label
Private lastUpdate As DateTime = DateTime.Now
Public DataSourceChanged As EventHandler
Public Property DataSource() As Object
Get
Return Me.dataGridView1.DataSource
End Get
Set
If DataSource IsNot Value Then
Me.dataGridView1.DataSource = Value
OnDataSourceChanged()
End If
End Set
End Property
Public Property DataMember() As String
Get
Return Me.dataGridView1.DataMember
End Get
Set
Me.dataGridView1.DataMember = value
End Set
End Property
Private Sub OnDataSourceChanged()
If (DataSourceChanged IsNot Nothing) Then
DataSourceChanged(Me, New EventArgs())
End If
End Sub
Public Sub New()
Me.dataGridView1 = New System.Windows.Forms.DataGridView()
Me.label1 = New System.Windows.Forms.Label()
Me.dataGridView1.ColumnHeadersHeightSizeMode = _
System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize
Me.dataGridView1.ImeMode = System.Windows.Forms.ImeMode.Disable
Me.dataGridView1.Location = New System.Drawing.Point(19, 55)
Me.dataGridView1.Size = New System.Drawing.Size(350, 150)
Me.dataGridView1.TabIndex = 1
Me.label1.AutoSize = True
Me.label1.Location = New System.Drawing.Point(19, 23)
Me.label1.Name = "label1"
Me.label1.Size = New System.Drawing.Size(76, 13)
Me.label1.TabIndex = 2
Me.label1.Text = "Customer List:"
Me.Controls.Add(Me.label1)
Me.Controls.Add(Me.dataGridView1)
Me.Size = New System.Drawing.Size(350, 216)
End Sub
End Class
// This class implements a simple user control
// that demonstrates how to apply the propertyNameChanged pattern.
[ComplexBindingProperties("DataSource", "DataMember")]
public class CustomerControl : UserControl
{
private DataGridView dataGridView1;
private Label label1;
private DateTime lastUpdate = DateTime.Now;
public EventHandler DataSourceChanged;
public object DataSource
{
get
{
return this.dataGridView1.DataSource;
}
set
{
if (DataSource != value)
{
this.dataGridView1.DataSource = value;
OnDataSourceChanged();
}
}
}
public string DataMember
{
get { return this.dataGridView1.DataMember; }
set { this.dataGridView1.DataMember = value; }
}
private void OnDataSourceChanged()
{
if (DataSourceChanged != null)
{
DataSourceChanged(this, new EventArgs());
}
}
public CustomerControl()
{
this.dataGridView1 = new System.Windows.Forms.DataGridView();
this.label1 = new System.Windows.Forms.Label();
this.dataGridView1.ColumnHeadersHeightSizeMode =
System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;
this.dataGridView1.ImeMode = System.Windows.Forms.ImeMode.Disable;
this.dataGridView1.Location = new System.Drawing.Point(19, 55);
this.dataGridView1.Size = new System.Drawing.Size(350, 150);
this.dataGridView1.TabIndex = 1;
this.label1.AutoSize = true;
this.label1.Location = new System.Drawing.Point(19, 23);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(76, 13);
this.label1.TabIndex = 2;
this.label1.Text = "Customer List:";
this.Controls.Add(this.label1);
this.Controls.Add(this.dataGridView1);
this.Size = new System.Drawing.Size(350, 216);
}
}
Compilazione del codice
Per compilare l'esempio di codice precedente:
- Incollare il codice in un file di codice vuoto. È necessario utilizzare il controllo personalizzato in un Windows Form contenente un metodo Main.
Vedere anche
Attività
Procedura: implementare l'interfaccia INotifyPropertyChanged
Concetti
Notifica delle modifiche nell'associazione dati dei Windows Form