How to: Bind a Windows Forms Control to a Type
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. 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. 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.
You can easily bind a control to a type with the BindingSource component.
Example
The following code example demonstrates how to bind a DataGridView control to a custom type by using a BindingSource component. 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. The example has an Add Customer button to add data to the DataGridView control. When you click the button, a new Customer object is added to the BindingSource. In a real-world scenario, the data might be obtained by a call to a Web service or other data source.
Imports System
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
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;
}
}
}
Compiling the Code
This example requires:
- References to the System and System.Windows.Forms assemblies.
For information about building this example from the command line for Visual Basic or Visual C#, see Building from the Command Line (Visual Basic) or Command-line Building With csc.exe. You can also build this example in Visual Studio by pasting the code into a new project. For more information, see How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio and How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio and How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio and How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio.