Gewusst wie: Binden eines Windows Forms-Steuerelements an einen TypHow to: Bind a Windows Forms Control to a Type

Beim Erstellen von Steuerelementen, die mit Daten interagieren, ist es manchmal erforderlich, ein Steuerelement an einen Typ statt an ein Objekt zu binden.When you are building controls that interact with data, you will sometimes find it necessary to bind a control to a type, rather than an object. Diese Situation tritt vor allem zur Entwurfszeit auf, wenn Daten möglicherweise nicht verfügbar sind, aber die datengebundenen Steuerelemente dennoch Informationen von der öffentlichen Schnittstelle eines Typs anzeigen müssen.This situation arises especially at design time, when data may not be available, but your data-bound controls still need to display information from a type's public interface. Sie können beispielsweise ein DataGridView-Steuerelement an ein von einem Webdienst bereitgestelltes Objekt binden, und dafür sorgen, dass das DataGridView-Steuerelement zur Entwurfszeit die zugehörigen Spalten mit den Membernamen eines benutzerdefinierten Typs beschriftet.For example, you may bind a DataGridView control to an object exposed by a Web service and want the DataGridView control to label its columns at design time with the member names of a custom type.

Mit der BindingSource-Komponente können Sie ein Steuerelement problemlos an einen Typ binden.You can easily bind a control to a type with the BindingSource component.

BeispielExample

Im folgenden Codebeispiel wird veranschaulicht, wie ein DataGridView-Steuerelement mithilfe einer BindingSource-Komponente an einen benutzerdefinierten Typ gebunden wird.The following code example demonstrates how to bind a DataGridView control to a custom type by using a BindingSource component. Beim Ausführen des Beispiels werden Sie feststellen, dass DataGridView die Spalten, die die Eigenschaften eines Customer-Objekts darstellen, beschriftet hat, bevor das Steuerelement mit Daten gefüllt wird.When you run the example, you'll notice the DataGridView has labeled columns that reflect the properties of a Customer object, before the control is populated with data. In dem Beispiel ist eine Schaltfläche "Add Customer" enthalten, mit der dem DataGridView-Steuerelement Daten hinzugefügt werden können.The example has an Add Customer button to add data to the DataGridView control. Wenn Sie auf die Schaltfläche klicken, wird Customer ein neues BindingSource-Objekt hinzugefügt.When you click the button, a new Customer object is added to the BindingSource. In einem realen Szenario könnten die Daten durch den Aufruf eines Webdiensts oder einer anderen Datenquelle abgerufen werden.In a real-world scenario, the data might be obtained by a call to a Web service or other data source.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Windows.Forms;

class Form1 : Form
{
    BindingSource bSource = new BindingSource();
    private Button button1;
    DataGridView dgv = new DataGridView();

    public Form1()
    {
        this.button1 = new System.Windows.Forms.Button();
        this.button1.Location = new System.Drawing.Point(140, 326);
        this.button1.Name = "button1";
        this.button1.AutoSize = true;
        this.button1.Text = "Add Customer";
        this.button1.Click += new System.EventHandler(this.button1_Click);
        this.ClientSize = new System.Drawing.Size(362, 370);
        this.Controls.Add(this.button1);

        // Bind the BindingSource to the DemoCustomer type.
        bSource.DataSource = typeof(DemoCustomer);

        // Set up the DataGridView control.
        dgv.Dock = DockStyle.Top;
        this.Controls.Add(dgv);

        // Bind the DataGridView control to the BindingSource.
        dgv.DataSource = bSource;
    }
    public static void Main()
    {
        Application.Run(new Form1());
    }

    private void button1_Click(object sender, EventArgs e)
    {
        bSource.Add(new DemoCustomer(DateTime.Today));
    }
}

// This simple class is used to demonstrate binding to a type.
public class DemoCustomer
{
    public DemoCustomer()
    {
        idValue = Guid.NewGuid();
    }

    public DemoCustomer(DateTime FirstOrderDate)
    {
        FirstOrder = FirstOrderDate;
        idValue = Guid.NewGuid();
    }
    // These fields hold the data that backs the public properties.
    private DateTime firstOrderDateValue;
    private Guid idValue;
    private string custNameValue;

    public string CustomerName
    {
        get { return custNameValue; }
        set { custNameValue = value; }
    }
    
    // This is a property that represents a birth date.
    public DateTime FirstOrder
    {
        get
        {
            return this.firstOrderDateValue;
        }
        set
        {
            if (value != this.firstOrderDateValue)
            {
                this.firstOrderDateValue = value;
            }
        }
    }

    // This is a property that represents a customer ID.
    public Guid ID
    {
        get
        {
            return this.idValue;
        }
    }
}
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Windows.Forms

Class Form1
    Inherits Form
    Private bSource As New BindingSource()
    Private WithEvents button1 As Button
    Private dgv As New DataGridView()

    Public Sub New()
        Me.button1 = New System.Windows.Forms.Button()
        Me.button1.Location = New System.Drawing.Point(140, 326)
        Me.button1.Name = "button1"
        Me.button1.AutoSize = True
        Me.button1.Text = "Add Customer"
        Me.ClientSize = New System.Drawing.Size(362, 370)
        Me.Controls.Add(Me.button1)

        ' Bind the BindingSource to the DemoCustomer type.
        bSource.DataSource = GetType(DemoCustomer)

        ' Set up the DataGridView control.
        dgv.Dock = DockStyle.Top
        Me.Controls.Add(dgv)

        ' Bind the DataGridView control to the BindingSource.
        dgv.DataSource = bSource

    End Sub

    Public Shared Sub Main()
        Application.Run(New Form1())

    End Sub

    Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) _
        Handles button1.Click
        bSource.Add(New DemoCustomer(DateTime.Today))

    End Sub
End Class

' This simple class is used to demonstrate binding to a type.
Public Class DemoCustomer

    Public Sub New()
        idValue = Guid.NewGuid()
    End Sub

    Public Sub New(ByVal FirstOrderDate As DateTime)
        FirstOrder = FirstOrderDate
        idValue = Guid.NewGuid()
    End Sub

    ' These fields hold the data that backs the public properties.
    Private firstOrderDateValue As DateTime
    Private idValue As Guid
    Private custNameValue As String

    Public Property CustomerName() As String
        Get
            Return custNameValue
        End Get
        Set(ByVal value As String)
            custNameValue = value
        End Set
    End Property

    ' This is a property that represents the first order date.
    Public Property FirstOrder() As DateTime
        Get
            Return Me.firstOrderDateValue
        End Get
        Set(ByVal value As DateTime)
            If value <> Me.firstOrderDateValue Then
                Me.firstOrderDateValue = value
            End If
        End Set
    End Property

    ' This is a property that represents a customer ID.
    Public ReadOnly Property ID() As Guid
        Get
            Return Me.idValue
        End Get
    End Property
End Class

Kompilieren des CodesCompiling the Code

Dieses Beispiel erfordert Folgendes:This example requires:

  • Verweise auf die Assemblys "System" und "System.Windows.Forms".References to the System and System.Windows.Forms assemblies.

Weitere InformationenSee also