Comment : accéder à des objets liés à des lignes DataGridView Windows Forms

  • Article

Il est parfois utile d’afficher une table d’informations stockée dans une collection d’objets métier. Quand vous liez un contrôle DataGridView à une telle collection, chaque propriété publique est affichée dans sa propre colonne, à moins que la propriété n'ait été marquée comme non consultable avec un BrowsableAttribute. Par exemple, une collection d’objets Customer aurait des colonnes telles que Nom et Adresse.

Si ces objets contiennent des informations supplémentaires et du code auquel vous souhaitez accéder, vous pouvez l'atteindre via des objets de ligne. Dans l'exemple de code suivant, les utilisateurs peuvent sélectionner plusieurs lignes et cliquer sur un bouton pour envoyer une facture à chacun des clients correspondants.

Pour accéder à des objets liés à une ligne

  • Utilisez la propriété DataGridViewRow.DataBoundItem.

    void invoiceButton_Click(object sender, EventArgs e)
{
    foreach (DataGridViewRow row in this.dataGridView1.SelectedRows)
    {
        Customer cust = row.DataBoundItem as Customer;
        if (cust != null)
        {
            cust.SendInvoice();
        }
    }
}

    Private Sub InvoiceButton_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles InvoiceButton.Click

    For Each row As DataGridViewRow In Me.DataGridView1.SelectedRows

        Dim cust As Customer = TryCast(row.DataBoundItem, Customer)
        If cust IsNot Nothing Then
            cust.SendInvoice()
        End If

    Next

End Sub

Exemple

L'exemple de code complet comprend une implémentation Customer simple et lie le DataGridView à un ArrayList contenant quelques objets Customer. Le gestionnaire d’événements Click du System.Windows.Forms.Button doit accéder aux objets Customer par l’intermédiaire des lignes, car la collection de clients n’est pas accessible en dehors du gestionnaire d’événements Form.Load.

using System;
using System.Windows.Forms;

public class DataGridViewObjectBinding : Form
{
    // These declarations and the Main() and New() methods
    // below can be replaced with designer-generated code.
    private Button invoiceButton = new Button();
    private DataGridView dataGridView1 = new DataGridView();

    // Entry point code.
    [STAThreadAttribute()]
    public static void Main()
    {
        Application.Run(new DataGridViewObjectBinding());
    }

    // Sets up the form.
    public DataGridViewObjectBinding()
    {
        this.dataGridView1.Dock = DockStyle.Fill;
        this.Controls.Add(this.dataGridView1);

        this.invoiceButton.Text = "invoice the selected customers";
        this.invoiceButton.Dock = DockStyle.Top;
        this.invoiceButton.Click += new EventHandler(invoiceButton_Click);
        this.Controls.Add(this.invoiceButton);

        this.Load += new EventHandler(DataGridViewObjectBinding_Load);
        this.Text = "DataGridView collection-binding demo";
    }

    void  DataGridViewObjectBinding_Load(object sender, EventArgs e)
    {
        // Set up a collection of objects for binding.
        System.Collections.ArrayList customers = new System.Collections.ArrayList();
        customers.Add(new Customer("Harry"));
        customers.Add(new Customer("Sally"));
        customers.Add(new Customer("Roy"));
        customers.Add(new Customer("Pris"));

        // Initialize and bind the DataGridView.
        this.dataGridView1.SelectionMode =
            DataGridViewSelectionMode.FullRowSelect;
        this.dataGridView1.AutoGenerateColumns = true;
        this.dataGridView1.DataSource = customers;
    }

    // Calls the SendInvoice() method for the Customer
    // object bound to each selected row.
    void invoiceButton_Click(object sender, EventArgs e)
    {
        foreach (DataGridViewRow row in this.dataGridView1.SelectedRows)
        {
            Customer cust = row.DataBoundItem as Customer;
            if (cust != null)
            {
                cust.SendInvoice();
            }
        }
    }
}

public class Customer
{
    private String nameValue;

    public Customer(String name)
    {
        nameValue = name;
    }

    public String Name
    {
        get
        {
            return nameValue;
        }
        set
        {
            nameValue = value;
        }
    }

    public void SendInvoice()
    {
        MessageBox.Show(nameValue + " has been billed.");
    }
}

Imports System.Windows.Forms

Public Class DataGridViewObjectBinding
    Inherits Form

    ' These declarations and the Main() and New() methods 
    ' below can be replaced with designer-generated code. 
    Private WithEvents InvoiceButton As New Button()
    Private WithEvents DataGridView1 As New DataGridView()

    ' Entry point code. 
    <STAThreadAttribute()> _
    Public Shared Sub Main()

        Application.Run(New DataGridViewObjectBinding())

    End Sub

    ' Sets up the form. 
    Public Sub New()

        Me.DataGridView1.Dock = DockStyle.Fill
        Me.Controls.Add(Me.DataGridView1)

        Me.InvoiceButton.Text = "invoice the selected customers"
        Me.InvoiceButton.Dock = DockStyle.Top
        Me.Controls.Add(Me.InvoiceButton)
        Me.Text = "DataGridView collection-binding demo"

    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles MyBase.Load

        ' Set up a collection of objects for binding.
        Dim customers As New System.Collections.ArrayList()
        customers.Add(New Customer("Harry"))
        customers.Add(New Customer("Sally"))
        customers.Add(New Customer("Roy"))
        customers.Add(New Customer("Pris"))

        ' Initialize and bind the DataGridView.
        Me.DataGridView1.SelectionMode = _
            DataGridViewSelectionMode.FullRowSelect
        Me.DataGridView1.AutoGenerateColumns = True
        Me.DataGridView1.DataSource = customers

    End Sub

    ' Calls the SendInvoice() method for the Customer 
    ' object bound to each selected row.
    Private Sub InvoiceButton_Click(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles InvoiceButton.Click

        For Each row As DataGridViewRow In Me.DataGridView1.SelectedRows

            Dim cust As Customer = TryCast(row.DataBoundItem, Customer)
            If cust IsNot Nothing Then
                cust.SendInvoice()
            End If

        Next

    End Sub

End Class

Public Class Customer

    Private nameValue As String

    Public Sub New(ByVal name As String)
        nameValue = name
    End Sub

    Public Property Name() As String
        Get
            Return nameValue
        End Get
        Set(ByVal value As String)
            nameValue = value
        End Set
    End Property

    Public Sub SendInvoice()
        MsgBox(nameValue & " has been billed.")
    End Sub

End Class

Compilation du code

Cet exemple nécessite :

  • des références aux assemblys System et System.Windows.Forms ;

Voir aussi