Procedura: condividere dati associati tra form tramite il componente BindingSource
È possibile condividere facilmente i dati tra i form con il componente BindingSource. Ad esempio, è possibile visualizzare un form di sola lettura che riepiloga i dati dell'origine dati e un altro form modificabile che contiene informazioni dettagliate sull'elemento attualmente selezionato nell'origine dati. L'esempio illustra questo scenario.
Esempio
L'esempio di codice seguente illustra come condividere un oggetto BindingSource e i dati associati tra i form. In questo esempio, l'oggetto BindingSource condiviso viene passato al costruttore del form figlio. Il form figlio consente all'utente di modificare i dati per l'elemento attualmente selezionato nel form principale.
Nota
Nell'esempio viene gestito l'evento BindingComplete del componente BindingSource per essere certi che i due form rimangano sincronizzati Per altre informazioni sul motivo per cui questa operazione viene eseguita, vedere Procedura: Garantire la sincronizzazione di più controlli associati alla stessa origine dati.
using System;
using System.Drawing;
using System.Windows.Forms;
using System.Data;
namespace BindingSourceMultipleForms
{
public class MainForm : Form
{
public MainForm()
{
this.Load += new EventHandler(MainForm_Load);
}
private BindingSource bindingSource1;
private Button button1;
private void MainForm_Load(object sender, EventArgs e)
{
InitializeData();
}
private void InitializeData()
{
bindingSource1 = new System.Windows.Forms.BindingSource();
// Handle the BindingComplete event to ensure the two forms
// remain synchronized.
bindingSource1.BindingComplete +=
new BindingCompleteEventHandler(bindingSource1_BindingComplete);
ClientSize = new System.Drawing.Size(292, 266);
DataSet dataset1 = new DataSet();
// Some xml data to populate the DataSet with.
string musicXml =
"<?xml version='1.0' encoding='UTF-8'?>" +
"<music>" +
"<recording><artist>Dave Matthews</artist>" +
"<cd>Under the Table and Dreaming</cd>" +
"<releaseDate>1994</releaseDate><rating>3.5</rating></recording>" +
"<recording><artist>Coldplay</artist><cd>X&Y</cd>" +
"<releaseDate>2005</releaseDate><rating>4</rating></recording>" +
"<recording><artist>Dave Matthews</artist>" +
"<cd>Live at Red Rocks</cd>" +
"<releaseDate>1997</releaseDate><rating>4</rating></recording>" +
"<recording><artist>U2</artist>" +
"<cd>Joshua Tree</cd><releaseDate>1987</releaseDate>" +
"<rating>5</rating></recording>" +
"<recording><artist>U2</artist>" +
"<cd>How to Dismantle an Atomic Bomb</cd>" +
"<releaseDate>2004</releaseDate><rating>4.5</rating></recording>" +
"<recording><artist>Natalie Merchant</artist>" +
"<cd>Tigerlily</cd><releaseDate>1995</releaseDate>" +
"<rating>3.5</rating></recording>" +
"</music>";
// Read the xml.
System.IO.StringReader reader = new System.IO.StringReader(musicXml);
dataset1.ReadXml(reader);
// Get a DataView of the table contained in the dataset.
DataTableCollection tables = dataset1.Tables;
DataView view1 = new DataView(tables[0]);
// Create a DataGridView control and add it to the form.
DataGridView datagridview1 = new DataGridView();
datagridview1.ReadOnly = true;
datagridview1.AutoGenerateColumns = true;
datagridview1.Width = 300;
this.Controls.Add(datagridview1);
bindingSource1.DataSource = view1;
datagridview1.DataSource = bindingSource1;
datagridview1.Columns.Remove("artist");
datagridview1.Columns.Remove("releaseDate");
// Create and add a button to the form.
button1 = new Button();
button1.AutoSize = true;
button1.Text = "Show/Edit Details";
this.Controls.Add(button1);
button1.Location = new Point(50, 200);
button1.Click += new EventHandler(button1_Click);
}
// Handle the BindingComplete event to ensure the two forms
// remain synchronized.
private void bindingSource1_BindingComplete(object sender, BindingCompleteEventArgs e)
{
if (e.BindingCompleteContext == BindingCompleteContext.DataSourceUpdate
&& e.Exception == null)
e.Binding.BindingManagerBase.EndCurrentEdit();
}
// The detailed form will be shown when the button is clicked.
private void button1_Click(object sender, EventArgs e)
{
DetailForm detailForm = new DetailForm(bindingSource1);
detailForm.Show();
}
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.Run(new MainForm());
}
}
// The detail form class.
public class DetailForm : Form
{
private BindingSource formDataSource;
// The constructor takes a BindingSource object.
public DetailForm(BindingSource dataSource)
{
formDataSource = dataSource;
this.ClientSize = new Size(240, 200);
TextBox textBox1 = new TextBox();
this.Text = "Selection Details";
textBox1.Width = 220;
TextBox textBox2 = new TextBox();
TextBox textBox3 = new TextBox();
TextBox textBox4 = new TextBox();
textBox4.Width = 30;
textBox3.Width = 50;
// Associate each text box with a column from the data source.
textBox1.DataBindings.Add("Text", formDataSource, "cd", true, DataSourceUpdateMode.OnPropertyChanged);
textBox2.DataBindings.Add("Text", formDataSource, "artist", true);
textBox3.DataBindings.Add("Text", formDataSource, "releaseDate", true);
textBox4.DataBindings.Add("Text", formDataSource, "rating", true);
textBox1.Location = new Point(10, 10);
textBox2.Location = new Point(10, 40);
textBox3.Location = new Point(10, 80);
textBox4.Location = new Point(10, 120);
this.Controls.AddRange(new Control[] { textBox1, textBox2, textBox3, textBox4 });
}
}
}
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Data
Public Class MainForm
Inherits Form
Public Sub New()
End Sub
Private WithEvents bindingSource1 As BindingSource
Private WithEvents button1 As Button
Private Sub MainForm_Load(ByVal sender As Object, ByVal e As EventArgs) _
Handles Me.Load
InitializeData()
End Sub
Private Sub InitializeData()
bindingSource1 = New System.Windows.Forms.BindingSource()
Dim dataset1 As New DataSet()
ClientSize = New System.Drawing.Size(292, 266)
' Some xml data to populate the DataSet with.
' Some xml data to populate the DataSet with.
Dim musicXml As String = "<?xml version='1.0' encoding='UTF-8'?>" & _
"<music><recording><artist>Dave Matthews</artist>" & _
"<cd>Under the Table and Dreaming</cd>" & _
"<releaseDate>1994</releaseDate><rating>3.5</rating></recording>" & _
"<recording><artist>Coldplay</artist><cd>X&Y</cd>" & _
"<releaseDate>2005</releaseDate><rating>4</rating></recording>" & _
"<recording><artist>Dave Matthews</artist>" & _
"<cd>Live at Red Rocks</cd>" & _
"<releaseDate>1997</releaseDate><rating>4</rating></recording>" & _
"<recording><artist>U2</artist>" & _
"<cd>Joshua Tree</cd><releaseDate>1987</releaseDate>" & _
"<rating>5</rating></recording>" & _
"<recording><artist>U2</artist>" & _
"<cd>How to Dismantle an Atomic Bomb</cd>" & _
"<releaseDate>2004</releaseDate><rating>4.5</rating></recording>" & _
"<recording><artist>Natalie Merchant</artist>" & _
"<cd>Tigerlily</cd><releaseDate>1995</releaseDate>" & _
"<rating>3.5</rating></recording>" & _
"</music>"
' Read the xml.
Dim reader As New System.IO.StringReader(musicXml)
dataset1.ReadXml(reader)
' Get a DataView of the table contained in the dataset.
Dim tables As DataTableCollection = dataset1.Tables
Dim view1 As New DataView(tables(0))
' Create a DataGridView control and add it to the form.
Dim datagridview1 As New DataGridView()
datagridview1.ReadOnly = True
datagridview1.AutoGenerateColumns = True
datagridview1.Width = 300
Me.Controls.Add(datagridview1)
bindingSource1.DataSource = view1
datagridview1.DataSource = bindingSource1
datagridview1.Columns.Remove("artist")
datagridview1.Columns.Remove("releaseDate")
' Create and add a button to the form.
button1 = New Button()
button1.AutoSize = True
button1.Text = "Show/Edit Details"
Me.Controls.Add(button1)
button1.Location = New Point(50, 200)
End Sub
' Handle the BindingComplete event to ensure the two forms
' remain synchronized.
Private Sub bindingSource1_BindingComplete(ByVal sender As Object, _
ByVal e As BindingCompleteEventArgs) Handles bindingSource1.BindingComplete
If e.BindingCompleteContext = BindingCompleteContext.DataSourceUpdate _
AndAlso e.Exception Is Nothing Then
e.Binding.BindingManagerBase.EndCurrentEdit()
End If
End Sub
' The detailed form will be shown when the button is clicked.
Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) _
Handles button1.Click
Dim detailForm As New DetailForm(bindingSource1)
detailForm.Show()
End Sub
<STAThread()> _
Shared Sub Main()
Application.EnableVisualStyles()
Application.Run(New MainForm())
End Sub
End Class
' The detail form class.
Public Class DetailForm
Inherits Form
Private formDataSource As BindingSource
' The constructor takes a BindingSource object.
Public Sub New(ByVal dataSource As BindingSource)
formDataSource = dataSource
Me.ClientSize = New Size(240, 200)
Dim textBox1 As New TextBox()
Me.Text = "Selection Details"
textBox1.Width = 220
Dim textBox2 As New TextBox()
Dim textBox3 As New TextBox()
Dim textBox4 As New TextBox()
textBox4.Width = 30
textBox3.Width = 50
' Associate each text box with a column from the data source.
textBox1.DataBindings.Add("Text", formDataSource, "cd", _
True, DataSourceUpdateMode.OnPropertyChanged)
textBox2.DataBindings.Add("Text", formDataSource, "artist", True)
textBox3.DataBindings.Add("Text", formDataSource, "releaseDate", True)
textBox4.DataBindings.Add("Text", formDataSource, "rating", True)
textBox1.Location = New Point(10, 10)
textBox2.Location = New Point(10, 40)
textBox3.Location = New Point(10, 80)
textBox4.Location = New Point(10, 120)
Me.Controls.AddRange(New Control() {textBox1, textBox2, textBox3, _
textBox4})
End Sub
End Class
Compilazione del codice
L'esempio presenta i requisiti seguenti:
- Riferimenti agli assembly System, System.Windows.Forms, System.Drawing, System.Data e System.Xml.
Vedi anche
Collabora con noi su GitHub
L'origine di questo contenuto è disponibile in GitHub, in cui è anche possibile creare ed esaminare i problemi e le richieste pull. Per ulteriori informazioni, vedere la guida per i collaboratori.
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