Export (0) Print
Expand All

Binding Class

Represents the simple binding between the property value of an object and the property value of a control.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

'Declaration
Public Class Binding
'Usage
Dim instance As Binding

public class Binding
public class Binding

Use the Binding class to create and maintain a simple binding between the property of a control and either the property of an object, or the property of the current object in a list of objects.

As an example of the first case, you can bind the Text property of a TextBox control to the FirstName property of a Customer object. As an example of the second case, you can bind the Text property of a TextBox control to the FirstName property of a DataTable that contains customers.

The Binding class also enables you to format values for display through the Format event and to retrieve formatted values through the Parse event.

When constructing a Binding instance with Binding constructor, you must specify three items:

  • The name of the control property to bind to.

  • The data source.

  • The navigation path that resolves to a list or property in the data source. The navigation path is also used to create the object's BindingMemberInfo property.

First, you must specify name of the control property you want to bind the data to. For example, to display data in a TextBox control, specify the Text property.

Second, you can specify an instance of any of classes in the following table as the data source.

Description

C# example

Any class that implements IBindingList or ITypedList. These include: DataSet, DataTable, DataView, or DataViewManager.

DataSet ds = new DataSet("myDataSet");

Any class that implements IList to create an indexed collection of objects. The collection must be created and filled before creating the Binding. The objects in the list must all be of the same type; otherwise, an exception will be thrown.

ArrayList ar1 = new ArrayList;

Customer1 cust1 = new Customer("Louis");

ar1.Add(cust1);

A strongly typed IList of strongly typed objects

Customer [] custList = new Customer[3];

Third, you must specify the navigation path, which can be an empty string (""), a single property name, or a period-delimited hierarchy of names. If you set the navigation path to an empty string, the ToString method will be called on the underlying data source object.

If the data source is a DataTable, which can contain multiple DataColumn objects, the navigation path must be used to resolve to a specific column.

NoteNote

When the data source is a DataSet, DataViewManager, or DataTable, you are actually binding to a DataView. Consequently, the bound rows are actually DataRowView objects.

A period-delimited navigation path is required when the data source is set to an object that contains multiple DataTable objects (such as a DataSet or DataViewManager). You can also use a period-delimited navigation path when you bind to an object whose properties return references to other objects (such as a class with properties that return other class objects). For example, the following navigation paths all describe valid data fields:

  • "Size.Height"

  • "Suppliers.CompanyName"

  • "Regions.regionsToCustomers.CustomerFirstName"

  • "Regions.regionsToCustomers.customersToOrders.ordersToDetails.Quantity"

Each member of the path can return either a property that resolves to a single value (such as an integer), or a list of values (such as an array of strings). Although each member in the path can be a list or property, the final member must resolve to a property. Each member builds on the previous member: "Size.Height" resolves to the Height property for the current Size; "Regions.regionsToCustomers.CustomerFirstName" resolves to the first name for the current customer, where the customer is one of the customers for the current region.

A DataRelation returns a list of values by linking one DataTable to a second DataTable in a DataSet. If the DataSet contains DataRelation objects, you can specify the data member as a TableName followed by a RelationName, and then a ColumnName. For example, if the DataTable named "Suppliers" contains a DataRelation named "suppliers2products", the data member could be "Suppliers.suppliers2products.ProductName".

The data source can consist of a set of related classes. For example, imagine a set of classes that catalogs solar systems. The class named System contains a property named Stars that returns a collection of Star objects. Each Star object has Name and Mass properties, as well as a Planets property that returns a collection of Planet objects. In this system, each planet also has Mass and Name properties. Each Planet object further has a Moons property that returns a collection of Moon objects, each of which also has Name and Mass properties. If you specify a System object as the data source, you can specify any of the following as the data member:

  • "Stars.Name"

  • "Stars.Mass"

  • "Stars.Planets.Name"

  • "Stars.Planets.Mass"

  • "Stars.Planets.Moons.Name"

  • "Stars.Planets.Moons.Mass"

Controls that can be simple-bound feature a collection of Binding objects in a ControlBindingsCollection, which you can access through the control's DataBindings property. You add a Binding to the collection by calling the Add method, thereby binding a property of the control to a property of an object (or to a property of the current object in a list).

You can simple-bind to any object that derives from the System.Windows.Forms.Control class, for example, the following Windows controls:

NoteNote

Only the SelectedValue property of the ComboBox, CheckedListBox, and ListBox control is simple bound.

The BindingManagerBase class is an abstract class that manages all the Binding objects for a particular data source and data member. Classes that derive from BindingManagerBase are the CurrencyManager and the PropertyManager classes. How a Binding is managed depends on whether the Binding is a list binding or a property binding. For example, if it is a list binding, you can use the BindingManagerBase to specify a Position in the list; the Position, therefore, determines which item (out of all items in the list) is actually bound to a control. To return the appropriate BindingManagerBase, use the BindingContext.

To add a new row to a set of controls bound to the same DataSource, use the AddNew method of the BindingManagerBase class. Use the Item property of the BindingContext class to return the appropriate CurrencyManager. To escape the addition of the new row, use the CancelCurrentEdit method.

The following code example creates a Windows Form with several controls that demonstrate simple data binding. The example creates a DataSet with two tables named Customers and Orders, and a DataRelation named custToOrders. Four controls (a DateTimePicker and three TextBox controls) are data bound to columns in the tables. For each control, the example creates and adds a Binding to the control through the DataBindings property. The example returns a BindingManagerBase for each table through the form's BindingContext. Four Button controls increment or decrement the Position property on the BindingManagerBase objects.

Imports System
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Globalization
Imports System.Windows.Forms

Public Class Form1
   Inherits Form

   Private components As Container
   Private button1 As Button
   Private button2 As Button
   Private button3 As Button
   Private button4 As Button
   Private text1 As TextBox
   Private text2 As TextBox
   Private text3 As TextBox

   Private bmCustomers As BindingManagerBase
   Private bmOrders As BindingManagerBase
   Private ds As DataSet
   Private DateTimePicker1 As DateTimePicker
   
   Public Sub New
      ' Required for Windows Form Designer support.
      InitializeComponent
      ' Call SetUp to bind the controls.
      SetUp
   End Sub

   Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
      If disposing Then
         If Not (components Is Nothing) Then
            components.Dispose()
         End If
      End If
      MyBase.Dispose(disposing)
    End Sub


   Private Sub InitializeComponent
      ' Create the form and its controls.
      With Me
         .components = New Container
         .button1 = New Button
         .button2 = New Button
         .button3 = New Button
         .button4 = New Button
         .text1 = New TextBox
         .text2 = New TextBox
         .text3 = New TextBox

         .DateTimePicker1 = New DateTimePicker
         
         .Text = "Binding Sample"
         .ClientSize = New Size(450, 200)

         With .button1
            .Location = New Point(24, 16)
            .Size = New Size(64, 24)
            .Text = "<"
            AddHandler button1.click, AddressOf button1_Click
         End With
         
         
         With .button2
            .Location = New Point(90, 16)
            .Size = New Size(64, 24)
            .Text = ">"
            AddHandler button2.click, AddressOf button2_Click
         End With
         
         With .button3
            .Location = New Point(90, 100)
            .Size = New Size(64, 24)
            .Text = ">"
            AddHandler button3.click, AddressOf button3_Click
         End With

         With .button4
            .Location = New Point(150, 100)
            .Size = New Size(64, 24)
            .Text = ">"
            AddHandler button4.click, AddressOf button4_Click
         End With

         With .text1
            .Location = New Point(24, 50)
            .Size = New Size(150, 24)
         End With

         With .text2
            .Location = New Point(190, 50)
            .Size = New Size(150, 24)
         End With

         With .text3
            .Location = New Point(290, 150)
            .Size = New Size(150, 24)
         End With

            With .DateTimePicker1
               .Location = New Point(90, 150)
               .Size = New Size(200, 800)
            End With

            With .Controls
            .Add(button1)
            .Add(button2)
            .Add(button3)
            .Add(button4)
            .Add(text1)
            .Add(text2)
            .Add(text3)
            .Add(DateTimePicker1)
            End With
      End With
   End Sub
      
   Public Shared Sub Main
      Application.Run(new Form1)
   End Sub

   Private Sub SetUp
      ' Create a DataSet with two tables and one relation.
      MakeDataSet
      BindControls
   End Sub

   Private Sub BindControls
      ' Create two Binding objects for the first two TextBox
      ' controls. The data-bound property for both controls
      ' is the Text property.  The data source is a DataSet
      ' (ds). The data member is the 
      ' TableName.ColumnName" string.

      text1.DataBindings.Add(New _
         Binding("Text", ds, "customers.custName"))
      text2.DataBindings.Add(New _
         Binding("Text", ds, "customers.custID"))
      ' Bind the DateTimePicker control by adding a new Binding.
      ' The data member of the DateTimePicker is a
      ' TableName.RelationName.ColumnName string
      DateTimePicker1.DataBindings.Add(New _
         Binding("Value", ds, "customers.CustToOrders.OrderDate"))
      ' Add event delegates for the Parse and Format events to a
      ' new Binding object, and add the object to the third
      ' TextBox control's BindingsCollection. The delegates
      ' must be added before adding the Binding to the
      ' collection; otherwise, no formatting occurs until
      ' the Current object of the BindingManagerBase for
      ' the data source changes.
      Dim b As Binding = New _
         Binding("Text", ds, "customers.custToOrders.OrderAmount")
      AddHandler b.Parse, AddressOf CurrencyStringToDecimal
      AddHandler b.Format, AddressOf DecimalToCurrencyString
      text3.DataBindings.Add(b)
      
         ' Get the BindingManagerBase for the Customers table.
         bmCustomers = Me.BindingContext(ds, "Customers")

         ' Get the BindingManagerBase for the Orders table using the
         ' RelationName.
         bmOrders = Me.BindingContext(ds, "customers.CustToOrders")
   End Sub

   Private Sub DecimalToCurrencyString(sender As Object, cevent As ConvertEventArgs)
      ' This method is the Format event handler. Whenever the 
      ' control displays a new value, the value is converted from 
      ' its native Decimal type to a string. The ToString method 
      ' then formats the value as a Currency, by using the 
      ' formatting character "c".

      ' The application can only convert to string type. 
   
      If Not cevent.DesiredType Is GetType(String) Then
         Exit Sub
      End If 
   
      cevent.Value = CType(cevent.Value, decimal).ToString("c")
   End Sub

   Private Sub CurrencyStringToDecimal(sender As Object, cevent As ConvertEventArgs)
      ' This method is the Parse event handler. The Parse event 
      ' occurs whenever the displayed value changes. The static 
      ' ToDecimal method of the Convert class converts the 
      ' value back to its native Decimal type.

      ' Can only convert to decimal type.
      If Not cevent.DesiredType Is GetType(decimal) Then
         Exit Sub
      End If

      cevent.Value = Decimal.Parse(cevent.Value.ToString, _
      NumberStyles.Currency, nothing)
      
      ' To see that no precision is lost, print the unformatted 
      ' value. For example, changing a value to "10.0001" 
      ' causes the control to display "10.00", but the 
      ' unformatted value remains "10.0001".
      Console.WriteLine(cevent.Value)
   End Sub

   Private Sub button1_Click(sender As Object, e As System.EventArgs)
      ' Go to the previous item in the Customer list.
      bmCustomers.Position -= 1
   End Sub

   Private Sub button2_Click(sender As Object, e As System.EventArgs)
      ' Go to the next item in the Customer list.
      bmCustomers.Position += 1
   End Sub

   Private Sub button3_Click(sender As Object, e As System.EventArgs)
      ' Go to the previous item in the Order list.
      bmOrders.Position -= 1
   End Sub

   Private Sub button4_Click(sender As Object, e As System.EventArgs)
      ' Go to the next item in the Orders list.
      bmOrders.Position += 1
   End Sub

   ' Creates a DataSet with two tables and populates it.
   Private Sub MakeDataSet
      ' Create a DataSet.
      ds = New DataSet("myDataSet")

      ' Creates two DataTables.
      Dim tCust As DataTable = New DataTable("Customers")
      Dim tOrders As DataTable = New DataTable("Orders")

      ' Create two columns, and add them to the first table.
      Dim cCustID As DataColumn = New DataColumn("CustID", _
      System.Type.GetType("System.Int32"))
      Dim cCustName As DataColumn = New DataColumn("CustName")
      tCust.Columns.Add(cCustID)
      tCust.Columns.Add(cCustName)

      ' Create three columns, and add them to the second table.
      Dim cID As DataColumn = _
         New DataColumn("CustID", System.Type.GetType("System.Int32"))
      Dim cOrderDate As DataColumn = _
         New DataColumn("orderDate", System.Type.GetType("System.DateTime"))
      Dim cOrderAmount As DataColumn = _
         New DataColumn("OrderAmount", System.Type.GetType("System.Decimal"))
      tOrders.Columns.Add(cOrderAmount)
      tOrders.Columns.Add(cID)
      tOrders.Columns.Add(cOrderDate)

      ' Add the tables to the DataSet.
      ds.Tables.Add(tCust)
      ds.Tables.Add(tOrders)

      ' Create a DataRelation, and add it to the DataSet.
      Dim dr As DataRelation = New _
         DataRelation("custToOrders", cCustID, cID)
      ds.Relations.Add(dr)
      
      ' Populate the tables. For each customer and orders,
      ' create two DataRow variables.
      Dim newRow1 As DataRow
      Dim newRow2 As DataRow

         ' Create three customers in the Customers Table.
         Dim i As Integer
         For i = 1 to 3
            newRow1 = tCust.NewRow
            newRow1("custID") = i
            ' Adds the row to the Customers table.
            tCust.Rows.Add(newRow1)
         Next

         ' Give each customer a distinct name.
         tCust.Rows(0)("custName") = "Alpha"
         tCust.Rows(1)("custName") = "Beta"
         tCust.Rows(2)("custName") = "Omega"

         ' For each customer, create five rows in the Orders table.
         Dim j As Integer
         For i = 1 to 3
         For j = 1 to 5
            newRow2 = tOrders.NewRow
            newRow2("CustID") = i
            newRow2("orderDate") = New DateTime(2001, i, j * 2)
            newRow2("OrderAmount") = i * 10 + j * .1
            ' Add the row to the Orders table.
            tOrders.Rows.Add(newRow2)
         Next
         Next
   End Sub
End Class

import System.*;
import System.Data.*;
import System.Drawing.*;
import System.Globalization.*;
import System.Windows.Forms.*;

public class Form1 extends System.Windows.Forms.Form
{
    private System.ComponentModel.Container components;
    private Button button1;
    private Button button2;
    private Button button3;
    private Button button4;
    private TextBox text1;
    private TextBox text2;
    private TextBox text3;
    private BindingManagerBase bmCustomers;
    private BindingManagerBase bmOrders;
    private DataSet ds;
    private DateTimePicker dateTimePicker1;

    public Form1()
    {
        // Required for Windows Form Designer support.
        InitializeComponent();
        // Call SetUp to bind the controls.
        SetUp();
    } //Form1

    private void InitializeComponent()
    {
        // Create the form and its controls.
        this.components = new System.ComponentModel.Container();
        this.button1 = new System.Windows.Forms.Button();
        this.button2 = new System.Windows.Forms.Button();
        this.button3 = new System.Windows.Forms.Button();
        this.button4 = new System.Windows.Forms.Button();
        this.text1 = new System.Windows.Forms.TextBox();
        this.text2 = new System.Windows.Forms.TextBox();
        this.text3 = new System.Windows.Forms.TextBox();
        this.dateTimePicker1 = new DateTimePicker();
        this.set_Text("Binding Sample");
        this.set_ClientSize(new System.Drawing.Size(450, 200));
        button1.set_Location(new System.Drawing.Point(24, 16));
        button1.set_Size(new System.Drawing.Size(64, 24));
        button1.set_Text("<");
        button1.add_Click(new System.EventHandler(button1_Click));
        button2.set_Location(new System.Drawing.Point(90, 16));
        button2.set_Size(new System.Drawing.Size(64, 24));
        button2.set_Text(">");
        button2.add_Click(new System.EventHandler(button2_Click));
        button3.set_Location(new System.Drawing.Point(90, 100));
        button3.set_Size(new System.Drawing.Size(64, 24));
        button3.set_Text("<");
        button3.add_Click(new System.EventHandler(button3_Click));
        button4.set_Location(new System.Drawing.Point(150, 100));
        button4.set_Size(new System.Drawing.Size(64, 24));
        button4.set_Text(">");
        button4.add_Click(new System.EventHandler(button4_Click));
        text1.set_Location(new System.Drawing.Point(24, 50));
        text1.set_Size(new System.Drawing.Size(150, 24));
        text2.set_Location(new System.Drawing.Point(190, 50));
        text2.set_Size(new System.Drawing.Size(150, 24));
        text3.set_Location(new System.Drawing.Point(290, 150));
        text3.set_Size(new System.Drawing.Size(150, 24));
        dateTimePicker1.set_Location(new System.Drawing.Point(90, 150));
        dateTimePicker1.set_Size(new System.Drawing.Size(200, 800));
        this.get_Controls().Add(button1);
        this.get_Controls().Add(button2);
        this.get_Controls().Add(button3);
        this.get_Controls().Add(button4);
        this.get_Controls().Add(text1);
        this.get_Controls().Add(text2);
        this.get_Controls().Add(text3);
        this.get_Controls().Add(dateTimePicker1);
    } //InitializeComponent

    protected void Dispose(boolean disposing)
    {
        if (disposing) {
            if (components != null) {
                components.Dispose();
            }
        }
        super.Dispose(disposing);
    } //Dispose

    public static void main(String[] args)
    {
        Application.Run(new Form1());
    } //main

    private void SetUp()
    {
        // Create a DataSet with two tables and one relation.
        MakeDataSet();
        BindControls();
    } //SetUp

    protected void BindControls()
    {
        /* Create two Binding objects for the first two TextBox 
           controls. The data-bound property for both controls 
           is the Text property. The data source is a DataSet 
           (ds). The data member is the  
           "TableName.ColumnName" string. 
         */
        text1.get_DataBindings().Add(new Binding("Text", ds, 
            "customers.custName"));
        text2.get_DataBindings().Add(new Binding("Text", ds, 
            "customers.custID"));

        /* Bind the DateTimePicker control by adding a new Binding. 
           The data member of the DateTimePicker is a 
           TableName.RelationName.ColumnName string. 
         */
        dateTimePicker1.get_DataBindings().Add(new Binding("Value", ds, 
            "customers.CustToOrders.OrderDate"));

        /* Add event delegates for the Parse and Format events to a 
           new Binding object, and add the object to the third 
           TextBox control's BindingsCollection. The delegates 
           must be added before adding the Binding to the 
           collection; otherwise, no formatting occurs until 
           the Current object of the BindingManagerBase for 
           the data source changes. 
         */
        Binding b = new Binding("Text", ds, 
            "customers.custToOrders.OrderAmount");

        b.add_Parse(new ConvertEventHandler(CurrencyStringToDecimal));
        b.add_Format(new ConvertEventHandler(DecimalToCurrencyString));
        text3.get_DataBindings().Add(b);

        // Get the BindingManagerBase for the Customers table. 
        bmCustomers = this.get_BindingContext().get_Item(ds, "Customers");

        /* Get the BindingManagerBase for the Orders table using the 
           RelationName. 
         */
        bmOrders = this.get_BindingContext().get_Item(ds, 
            "customers.CustToOrders");
    } //BindControls

    private void DecimalToCurrencyString(Object sender, ConvertEventArgs cevent)
    {
        /* This method is the Format event handler. Whenever the 
           control displays a new value, the value is converted from 
           its native Decimal type to a string. The ToString method 
           then formats the value as a Currency, by using the 
           formatting character "c". 
         */

        // The application can only convert to string type. 
        if (!cevent.get_DesiredType().Equals(String.class.ToType())) {
            return;
        }
        cevent.set_Value(((System.Decimal)(cevent.get_Value())).ToString("c"));
    } //DecimalToCurrencyString

    private void CurrencyStringToDecimal(Object sender, ConvertEventArgs cevent)
    {
        /* This method is the Parse event handler. The Parse event 
           occurs whenever the displayed value changes. The static 
           ToDecimal method of the Convert class converts the 
           value back to its native Decimal type. 
         */

        // Can only convert to decimal type.
        if (!cevent.get_DesiredType().Equals(System.Decimal.class.ToType())) {
            return;
        }
        cevent.set_Value(Decimal.Parse(cevent.get_Value().ToString(), 
            NumberStyles.Currency, null));

        /* To see that no precision is lost, print the unformatted 
           value. For example, changing a value to "10.0001" 
           causes the control to display "10.00", but the 
           unformatted value remains "10.0001". 
         */
        Console.WriteLine(cevent.get_Value());
    } //CurrencyStringToDecimal

    protected void button1_Click(Object sender, System.EventArgs e)
    {
        // Go to the previous item in the Customer list.
        bmCustomers.set_Position(bmCustomers.get_Position() - 1);
    } //button1_Click

    protected void button2_Click(Object sender, System.EventArgs e)
    {
        // Go to the next item in the Customer list.
        bmCustomers.set_Position(bmCustomers.get_Position() + 1);
    } //button2_Click

    protected void button3_Click(Object sender, System.EventArgs e)
    {
        // Go to the previous item in the Orders list.
        bmOrders.set_Position(bmOrders.get_Position() - 1);
    } //button3_Click

    protected void button4_Click(Object sender, System.EventArgs e)
    {
        // Go to the next item in the Orders list.
        bmOrders.set_Position(bmOrders.get_Position() + 1);
    } //button4_Click

    // Create a DataSet with two tables and populate it.
    private void MakeDataSet()
    {
        // Create a DataSet.
        ds = new DataSet("myDataSet");

        // Create two DataTables.
        DataTable tCust = new DataTable("Customers");
        DataTable tOrders = new DataTable("Orders");

        // Create two columns, and add them to the first table.
        DataColumn cCustID = new DataColumn("CustID", int.class.ToType());
        DataColumn cCustName = new DataColumn("CustName");

        tCust.get_Columns().Add(cCustID);
        tCust.get_Columns().Add(cCustName);

        // Create three columns, and add them to the second table.
        DataColumn cID = new DataColumn("CustID", int.class.ToType());
        DataColumn cOrderDate = new DataColumn("orderDate", 
            DateTime.class.ToType());
        DataColumn cOrderAmount = new DataColumn("OrderAmount", 
            System.Decimal.class.ToType());

        tOrders.get_Columns().Add(cOrderAmount);
        tOrders.get_Columns().Add(cID);
        tOrders.get_Columns().Add(cOrderDate);

        // Add the tables to the DataSet.
        ds.get_Tables().Add(tCust);
        ds.get_Tables().Add(tOrders);

        // Create a DataRelation, and add it to the DataSet.
        DataRelation dr = new DataRelation("custToOrders", cCustID, cID);
        ds.get_Relations().Add(dr);

        /* Populate the tables. For each customer and order, 
           create two DataRow variables. 
         */
        DataRow newRow1;
        DataRow newRow2;

        // Create three customers in the Customers Table.
        for (int i = 1; i < 4; i++) {
            newRow1 = tCust.NewRow();
            newRow1.set_Item("custID", (Int32)i);
            // Add the row to the Customers table.
            tCust.get_Rows().Add(newRow1);
        }

        // Give each customer a distinct name.
        tCust.get_Rows().get_Item(0).set_Item("custName", "Alpha");
        tCust.get_Rows().get_Item(1).set_Item("custName", "Beta");
        tCust.get_Rows().get_Item(2).set_Item("custName", "Omega");

        // For each customer, create five rows in the Orders table.
        for (int i = 1; i < 4; i++) {
            for (int j = 1; j < 6; j++) {
                newRow2 = tOrders.NewRow();
                newRow2.set_Item("CustID", (Int32)i);
                newRow2.set_Item("orderDate", new DateTime(2001, i, j * 2));
                newRow2.set_Item("OrderAmount",    
                    (System.Double)(i * 10 + j * 0.1));
                // Add the row to the Orders table.
                tOrders.get_Rows().Add(newRow2);
            }
        }
    } //MakeDataSet
} //Form1

import System;
import System.Data;
import System.Drawing;
import System.Globalization;
import System.Windows.Forms;

public class Form1 extends System.Windows.Forms.Form
{
   private var components : System.ComponentModel.Container;
   private var button1 : Button;
   private var button2 : Button;
   private var button3 : Button;
   private var button4 : Button;
   private var text1 : TextBox;
   private var text2 : TextBox;
   private var text3 : TextBox;

   private var bmCustomers : BindingManagerBase;
   private var bmOrders : BindingManagerBase;
   private var ds : DataSet;
   private var DateTimePicker1 : DateTimePicker;

   public function Form1()
   {
      // Required for Windows Form Designer support.
      InitializeComponent();
      // Call SetUp to bind the controls.
      SetUp();
   }
 
   private function InitializeComponent()
   {
      // Create the form and its controls.
      this.components = new System.ComponentModel.Container();
      this.button1 = new System.Windows.Forms.Button();
      this.button2 = new System.Windows.Forms.Button();
      this.button3 = new System.Windows.Forms.Button();
      this.button4 = new System.Windows.Forms.Button();
      
      this.text1= new System.Windows.Forms.TextBox();
      this.text2= new System.Windows.Forms.TextBox();
      this.text3= new System.Windows.Forms.TextBox();
      
      this.DateTimePicker1 = new DateTimePicker();
      
      this.Text = "Binding Sample";
      this.ClientSize = new System.Drawing.Size(450, 200);
      
      button1.Location = new System.Drawing.Point(24, 16);
      button1.Size = new System.Drawing.Size(64, 24);
      button1.Text = "<";
      button1.add_Click(button1_Click);

      button2.Location = new System.Drawing.Point(90, 16);
      button2.Size = new System.Drawing.Size(64, 24);
      button2.Text = ">";
      button2.add_Click(button2_Click);

      button3.Location = new System.Drawing.Point(90, 100);
      button3.Size = new System.Drawing.Size(64, 24);
      button3.Text = "<";
      button3.add_Click(button3_Click);

      button4.Location = new System.Drawing.Point(150, 100);
      button4.Size = new System.Drawing.Size(64, 24);
      button4.Text = ">";
      button4.add_Click(button4_Click);

      text1.Location = new System.Drawing.Point(24, 50);
      text1.Size = new System.Drawing.Size(150, 24);

      text2.Location = new System.Drawing.Point(190, 50);
      text2.Size = new System.Drawing.Size(150, 24);

      text3.Location = new System.Drawing.Point(290, 150);
      text3.Size = new System.Drawing.Size(150, 24);
      
      DateTimePicker1.Location = new System.Drawing.Point(90, 150);
      DateTimePicker1.Size = new System.Drawing.Size(200, 800);
      
      this.Controls.Add(button1);
      this.Controls.Add(button2);
      this.Controls.Add(button3);
      this.Controls.Add(button4);
      this.Controls.Add(text1);
      this.Controls.Add(text2);
      this.Controls.Add(text3);
      this.Controls.Add(DateTimePicker1);
   }

   protected override function Dispose(disposing : boolean){
      if( disposing ){
         if (components != null){
            components.Dispose();}
      }
      super.Dispose( disposing );
   }

   public static function Main()
   {
      Application.Run(new Form1());
   }
   
   private function SetUp()
   {
      // Create a DataSet with two tables and one relation.
      MakeDataSet();
      BindControls();
   }

   protected function BindControls()
   {
      /* Create two Binding objects for the first two TextBox 
         controls. The data-bound property for both controls 
         is the Text property. The data source is a DataSet 
         (ds). The data member is the  
         "TableName.ColumnName" string. */
      text1.DataBindings.Add(new Binding
      ("Text", ds, "customers.custName"));
      text2.DataBindings.Add(new Binding
      ("Text", ds, "customers.custID"));
      
      /* Bind the DateTimePicker control by adding a new Binding. 
         The data member of the DateTimePicker is a 
         TableName.RelationName.ColumnName string. */
      DateTimePicker1.DataBindings.Add(new 
      Binding("Value", ds, "customers.CustToOrders.OrderDate"));

      /* Add event delegates for the Parse and Format events to a 
         new Binding object, and add the object to the third 
         TextBox control's BindingsCollection. The delegates 
         must be added before adding the Binding to the 
         collection; otherwise, no formatting occurs until 
         the Current object of the BindingManagerBase for 
         the data source changes. */
      var b : Binding = new Binding
         ("Text", ds, "customers.custToOrders.OrderAmount");
      b.add_Parse(CurrencyStringToDecimal);
      b.add_Format(DecimalToCurrencyString);
      text3.DataBindings.Add(b);

      // Get the BindingManagerBase for the Customers table. 
      bmCustomers = this.BindingContext [ds, "Customers"];

      /* Get the BindingManagerBase for the Orders table using the 
         RelationName. */ 
      bmOrders = this.BindingContext[ds, "customers.CustToOrders"];
   }

   private function DecimalToCurrencyString(sender, cevent : ConvertEventArgs)
   {
      /* This method is the Format event handler. Whenever the 
         control displays a new value, the value is converted from 
         its native Decimal type to a string. The ToString method 
         then formats the value as a Currency, by using the 
         formatting character "c". */

      // The application can only convert to string type. 
      if(cevent.DesiredType != String.GetType()) return;

      cevent.Value = (Decimal(cevent.Value)).ToString("c");
   }

   private function CurrencyStringToDecimal(sender, cevent : ConvertEventArgs)
   {   
      /* This method is the Parse event handler. The Parse event 
         occurs whenever the displayed value changes. The static 
         ToDecimal method of the Convert class converts the 
         value back to its native Decimal type. */

      // Can only convert to Decimal type.
      if(cevent.DesiredType != Decimal.GetType()) return;

      cevent.Value = Decimal.Parse(cevent.Value.ToString(),
      	NumberStyles.Currency, null);

      /* To see that no precision is lost, print the unformatted 
         value. For example, changing a value to "10.0001" 
         causes the control to display "10.00", but the 
         unformatted value remains "10.0001". */
      Console.WriteLine(cevent.Value);
   }

   protected function button1_Click(sender, e : System.EventArgs)
   {
      // Go to the previous item in the Customer list.
      bmCustomers.Position -= 1;
   }

   protected function button2_Click(sender, e : System.EventArgs)
   {
      // Go to the next item in the Customer list.
      bmCustomers.Position += 1;
   }
    
   protected function button3_Click(sender, e : System.EventArgs)
   {
      // Go to the previous item in the Orders list.
      bmOrders.Position-=1;
   }

   protected function button4_Click(sender, e : System.EventArgs)
   {
      // Go to the next item in the Orders list.
      bmOrders.Position+=1;
   }

   // Create a DataSet with two tables and populate it.
   private function MakeDataSet()
   {
      // Create a DataSet.
      ds = new DataSet("myDataSet");
      
      // Create two DataTables.
      var tCust : DataTable = new DataTable("Customers");
      var tOrders : DataTable= new DataTable("Orders");

      // Create two columns, and add them to the first table.
      var cCustID : DataColumn = new DataColumn("CustID", Int32);
      var cCustName : DataColumn = new DataColumn("CustName");
      tCust.Columns.Add(cCustID);
      tCust.Columns.Add(cCustName);

      // Create three columns, and add them to the second table.
      var cID : DataColumn  = 
         new DataColumn("CustID", Int32);
      var cOrderDate : DataColumn  = 
         new DataColumn("orderDate", DateTime);
      var cOrderAmount : DataColumn = 
         new DataColumn("OrderAmount", Decimal);
      tOrders.Columns.Add(cOrderAmount);
      tOrders.Columns.Add(cID);
      tOrders.Columns.Add(cOrderDate);

      // Add the tables to the DataSet.
      ds.Tables.Add(tCust);
      ds.Tables.Add(tOrders);

      // Create a DataRelation, and add it to the DataSet.
      var dr : DataRelation = new DataRelation
      ("custToOrders", cCustID , cID);
      ds.Relations.Add(dr);
   
      /* Populate the tables. For each customer and order, 
         create two DataRow variables. */
      var newRow1 : DataRow;
      var newRow2 : DataRow;

      // Create three customers in the Customers Table.
      for(var i : int = 1; i < 4; i++)
      {
         newRow1 = tCust.NewRow();
         newRow1["custID"] = i;
         // Add the row to the Customers table.
         tCust.Rows.Add(newRow1);
      }
      // Give each customer a distinct name.
      tCust.Rows[0]["custName"] = "Alpha";
      tCust.Rows[1]["custName"] = "Beta";
      tCust.Rows[2]["custName"] = "Omega";
      
      // For each customer, create five rows in the Orders table.
      for(var j : int = 1; j < 4; j++)
      {
         for(var k : int = 1; k < 6; k++)
         {
            newRow2 = tOrders.NewRow();
            newRow2["CustID"]= j;
            newRow2["orderDate"]= new DateTime(2001, j, k * 2);
            newRow2["OrderAmount"] = j * 10 + k  * .1;
            // Add the row to the Orders table.
            tOrders.Rows.Add(newRow2);
         }
      }
   }
 }


System.Object
  System.Windows.Forms.Binding

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

Community Additions

ADD
Show:
© 2014 Microsoft