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How to: Share Bound Data Across Forms Using the BindingSource Component

You can easily share data across forms using the BindingSource component. For example, you may want to display one read-only form that summarizes the data-source data and another editable form that contains detailed information about the currently selected item in the data source. This example demonstrates this scenario.

The following code example demonstrates how to share a BindingSource and its bound data across forms. In this example, the shared BindingSource is passed to the constructor of the child form. The child form allows the user to edit the data for the currently selected item in the main form.

Note Note

The BindingComplete event for the BindingSource component is handled in the example to ensure that the two forms remain synchronized. For more information about why this is done, see How to: Ensure Multiple Controls Bound to the Same Data Source Remain Synchronized.

Imports System
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&amp;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

This example requires:

  • References to the System, System.Windows.Forms, System.Drawing, System.Data, and System.Xml 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. How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio
How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio
How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio
How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio
How to: Compile and Run a Complete Windows Forms Code Example Using Visual Studio

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