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Procedure: Toegang krijgen tot objecten die zijn gebonden aan Windows Forms DataGridView-rijen

Soms is het handig om een tabel weer te geven met informatie die is opgeslagen in een verzameling zakelijke objecten. Wanneer u een DataGridView besturingselement verbindt met een dergelijke verzameling, wordt elke openbare eigenschap weergegeven in een eigen kolom, tenzij de eigenschap is gemarkeerd als niet-bladerbaar met een BrowsableAttribute. Een verzameling Customer objecten bevat bijvoorbeeld kolommen zoals Name en Address.

Als deze objecten aanvullende informatie en code bevatten die u wilt openen, kunt u deze bereiken via rijobjecten. In het volgende codevoorbeeld kunnen gebruikers meerdere rijen selecteren en op een knop klikken om een factuur naar elk van de bijbehorende klanten te verzenden.

Toegang krijgen tot rijgebonden objecten

  • Gebruik de eigenschap 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

Voorbeeld

Het volledige codevoorbeeld bevat een eenvoudige Customer-implementatie en verbindt de DataGridView met een ArrayList met enkele Customer objecten. De Click event handler van de System.Windows.Forms.Button moet toegang krijgen tot de Customer objecten via de rijen, omdat de klantencollectie niet toegankelijk is buiten de Form.Load event handler.

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

De code compileren

Voor dit voorbeeld is het volgende vereist:

  • Verwijzingen naar de assemblies System en System.Windows.Forms.

Zie ook

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