Binding 類別

定義

表示物件屬性值和控制項屬性值之間的簡單繫結 (Simple Binding)。Represents the simple binding between the property value of an object and the property value of a control.

public ref class Binding
[System.ComponentModel.TypeConverter(typeof(System.Windows.Forms.ListBindingConverter))]
public class Binding
type Binding = class
Public Class Binding
繼承
Binding
屬性

範例

下列程式碼範例會建立 Windows Form,其中包含數個示範簡單資料系結的控制項。The following code example creates a Windows Form with several controls that demonstrate simple data binding. 此範例會建立 DataSet,其中包含兩個數據表,名為 CustomersOrders,而 DataRelation 名為 custToOrdersThe example creates a DataSet with two tables named Customers and Orders, and a DataRelation named custToOrders. 四個控制項(DateTimePicker 和三個 @no__t 1 控制項)系結至資料表中的資料行。Four controls (a DateTimePicker and three TextBox controls) are data bound to columns in the tables. 針對每個控制項,此範例會透過 DataBindings 屬性來建立 Binding,並將其新增至控制項。For each control, the example creates and adds a Binding to the control through the DataBindings property. 此範例會透過表單的 BindingContext,傳回每個資料表的 BindingManagerBaseThe example returns a BindingManagerBase for each table through the form's BindingContext. 四個 Button 控制項遞增或遞減 @no__t 2 物件上的 Position 屬性。Four Button controls increment or decrement the Position property on the BindingManagerBase objects.

#using <system.dll>
#using <system.data.dll>
#using <system.drawing.dll>
#using <system.windows.forms.dll>
#using <system.xml.dll>

using namespace System;
using namespace System::Data;
using namespace System::Drawing;
using namespace System::Globalization;
using namespace System::Windows::Forms;

#define null 0L
public ref class Form1: public Form
{
private:
   System::ComponentModel::Container^ components;
   Button^ button1;
   Button^ button2;
   Button^ button3;
   Button^ button4;
   TextBox^ text1;
   TextBox^ text2;
   TextBox^ text3;
   BindingManagerBase^ bmCustomers;
   BindingManagerBase^ bmOrders;
   DataSet^ ds;
   DateTimePicker^ DateTimePicker1;

public:
   Form1()
   {
      // Required for Windows Form Designer support.
      InitializeComponent();

      // Call SetUp to bind the controls.
      SetUp();
   }

private:
   void InitializeComponent()
   {
      // Create the form and its controls.
      this->components = gcnew System::ComponentModel::Container;
      this->button1 = gcnew Button;
      this->button2 = gcnew Button;
      this->button3 = gcnew Button;
      this->button4 = gcnew Button;
      this->text1 = gcnew TextBox;
      this->text2 = gcnew TextBox;
      this->text3 = gcnew TextBox;
      this->DateTimePicker1 = gcnew DateTimePicker;
      this->Text =  "Binding Sample";
      this->ClientSize = System::Drawing::Size( 450, 200 );
      button1->Location = System::Drawing::Point( 24, 16 );
      button1->Size = System::Drawing::Size( 64, 24 );
      button1->Text =  "<";
      button1->Click += gcnew System::EventHandler( this, &Form1::button1_Click );
      button2->Location = System::Drawing::Point( 90, 16 );
      button2->Size = System::Drawing::Size( 64, 24 );
      button2->Text =  ">";
      button2->Click += gcnew System::EventHandler( this, &Form1::button2_Click );
      button3->Location = System::Drawing::Point( 90, 100 );
      button3->Size = System::Drawing::Size( 64, 24 );
      button3->Text =  "<";
      button3->Click += gcnew System::EventHandler( this, &Form1::button3_Click );
      button4->Location = System::Drawing::Point( 150, 100 );
      button4->Size = System::Drawing::Size( 64, 24 );
      button4->Text =  ">";
      button4->Click += gcnew System::EventHandler( this, &Form1::button4_Click );
      text1->Location = System::Drawing::Point( 24, 50 );
      text1->Size = System::Drawing::Size( 150, 24 );
      text2->Location = System::Drawing::Point( 190, 50 );
      text2->Size = System::Drawing::Size( 150, 24 );
      text3->Location = System::Drawing::Point( 290, 150 );
      text3->Size = System::Drawing::Size( 150, 24 );
      DateTimePicker1->Location = System::Drawing::Point( 90, 150 );
      DateTimePicker1->Size = 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 );
   }

public:
   ~Form1()
   {
      if ( components != nullptr )
      {
         delete components;
      }
   }

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

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->DataBindings->Add( gcnew Binding( "Text",ds,"customers.custName" ) );
      text2->DataBindings->Add( gcnew 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( gcnew 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 = gcnew Binding( "Text",ds,"customers.custToOrders.OrderAmount" );
      b->Parse += gcnew ConvertEventHandler( this, &Form1::CurrencyStringToDecimal );
      b->Format += gcnew ConvertEventHandler( this, &Form1::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:
   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->DesiredType != String::typeid )
            return;

      cevent->Value = (dynamic_cast<Decimal^>(cevent->Value))->ToString( "c" );
   }

   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->DesiredType != Decimal::typeid )
            return;

      cevent->Value = Decimal::Parse( cevent->Value->ToString(), NumberStyles::Currency, nullptr );
      
      /* 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 );
   }

private:
   void button1_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Go to the previous item in the Customer list.
      bmCustomers->Position -= 1;
   }

   void button2_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Go to the next item in the Customer list.
      bmCustomers->Position += 1;
   }

   void button3_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      
      // Go to the previous item in the Orders list.
      bmOrders->Position = bmOrders->Position - 1;
   }

   void button4_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      
      // Go to the next item in the Orders list.
      bmOrders->Position = bmOrders->Position + 1;
   }

private:

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

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

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

      // Create three columns, and add them to the second table.
      DataColumn^ cID = gcnew DataColumn( "CustID",Int32::typeid );
      DataColumn^ cOrderDate = gcnew DataColumn( "orderDate",DateTime::typeid );
      DataColumn^ cOrderAmount = gcnew DataColumn( "OrderAmount",Decimal::typeid );
      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.
      DataRelation^ dr = gcnew DataRelation( "custToOrders",cCustID,cID );
      ds->Relations->Add( dr );
      
      /* Populate the tables. For each customer and order, 
              create two DataRow variables. */
      DataRow^ newRow1; // = new DataRow();

      DataRow^ newRow2; // = new DataRow();

      // Create three customers in the Customers Table.
      for ( int i = 1; i < 4; i++ )
      {
         newRow1 = tCust->NewRow();
         newRow1[ "custID" ] = i;
         
         // Add the row to the Customers table.
         tCust->Rows->Add( newRow1 );

      }
      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 ( int i = 1; i < 4; i++ )
      {
         for ( int j = 1; j < 6; j++ )
         {
            newRow2 = tOrders->NewRow();
            newRow2[ "CustID" ] = i;
            newRow2[ "orderDate" ] = System::DateTime( 2001, i, j * 2 );
            newRow2[ "OrderAmount" ] = i * 10 + j * .1;
            
            // Add the row to the Orders table.
            tOrders->Rows->Add( newRow2 );
         }
      }
   }
};

int main()
{
   Application::Run( gcnew Form1 );
}
using System;
using System.Data;
using System.Drawing;
using System.Globalization;
using System.Windows.Forms;

public class Form1 : 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();
   }
 
   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.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.Click+=new System.EventHandler(button1_Click);

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

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

      button4.Location = new System.Drawing.Point(150, 100);
      button4.Size = new System.Drawing.Size(64, 24);
      button4.Text = ">";
      button4.Click+=new System.EventHandler(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 void Dispose( bool disposing ){
      if( disposing ){
         if (components != null){
            components.Dispose();}
      }
      base.Dispose( disposing );
   }
   public static void Main()
   {
      Application.Run(new Form1());
   }
   
   private void SetUp()
   {
      // Create a DataSet with two tables and one relation.
      MakeDataSet();
      BindControls();
   }

   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.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. */
      Binding b = new Binding
         ("Text", ds, "customers.custToOrders.OrderAmount");
      b.Parse+=new ConvertEventHandler(CurrencyStringToDecimal);
      b.Format+=new ConvertEventHandler(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 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.DesiredType != typeof(string)) return;

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

   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.DesiredType != typeof(decimal)) 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);
   }

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

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

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

   // 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", typeof(int));
      DataColumn cCustName = new DataColumn("CustName");
      tCust.Columns.Add(cCustID);
      tCust.Columns.Add(cCustName);

      // Create three columns, and add them to the second table.
      DataColumn cID = 
         new DataColumn("CustID", typeof(int));
      DataColumn cOrderDate = 
         new DataColumn("orderDate",typeof(DateTime));
      DataColumn cOrderAmount = 
         new DataColumn("OrderAmount", typeof(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.
      DataRelation dr = new DataRelation
      ("custToOrders", cCustID , cID);
      ds.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["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(int i = 1; i < 4; i++)
      {
         for(int j = 1; j < 6; j++)
         {
            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);
         }
      }
   }
 }

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 (components IsNot 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 cevent.DesiredType IsNot 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 cevent.DesiredType IsNot 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

備註

使用 Binding 類別,在控制項的屬性和物件的屬性,或物件清單中目前物件的屬性之間建立和維護簡單的系結。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.

作為第一個案例的範例,您可以將 @no__t 1 控制項的 Text 屬性系結至 Customer 物件的 FirstName 屬性。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. 作為第二個案例的範例,您可以將 @no__t 1 控制項的 Text 屬性系結至包含客戶之 DataTable 的 @no__t 2 屬性。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.

@No__t 0 類別也可讓您將值格式化,以便透過 Format 事件來顯示,以及透過 @no__t 2 事件來抓取格式化的值。The Binding class also enables you to format values for display through the Format event and to retrieve formatted values through the Parse event.

使用 Binding 的函式來建立 Binding 實例時,您必須指定三個專案:When constructing a Binding instance with Binding constructor, you must specify three items:

  • 要系結之控制項屬性的名稱。The name of the control property to bind to.

  • 資料來源。The data source.

  • 解析為數據源中清單或屬性的導覽路徑。The navigation path that resolves to a list or property in the data source. 導覽路徑也會用來建立物件的 BindingMemberInfo 屬性。The navigation path is also used to create the object's BindingMemberInfo property.

首先,您必須指定您想要系結資料之控制項屬性的名稱。First, you must specify name of the control property you want to bind the data to. 例如,若要顯示 @no__t 0 控制項中的資料,請指定 Text 屬性。For example, to display data in a TextBox control, specify the Text property.

第二,您可以指定下表中任何一個類別的實例做為資料來源。Second, you can specify an instance of any one of the classes in the following table as the data source.

說明Description C# 範例C# example
任何會執行 IBindingListITypedList 的類別。Any class that implements IBindingList or ITypedList. 其中包括下列各項: DataSetDataTableDataViewDataViewManagerThese include the following: DataSet, DataTable, DataView, or DataViewManager. DataSet ds = new DataSet("myDataSet");
任何會執行 IList 的類別,以建立物件的索引集合。Any class that implements IList to create an indexed collection of objects. 建立 Binding 之前,必須先建立並填入集合。The collection must be created and filled before creating the Binding. 清單中的物件必須是相同的類型;否則,將會擲回例外狀況。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);
強型別物件的強型別 IListA strongly typed IList of strongly typed objects Customer [] custList = new Customer[3];

第三,您必須指定導覽路徑,它可以是空字串("")、單一屬性名稱或以句點分隔的名稱階層。Third, you must specify the navigation path, which can be an empty string (""), a single property name, or a period-delimited hierarchy of names. 如果您將導覽路徑設定為空字串,則會在基礎資料來源物件上呼叫 ToString 方法。If you set the navigation path to an empty string, the ToString method will be called on the underlying data source object.

如果資料來源是 DataTable,其中可以包含多個 @no__t 1 的物件,則必須使用導覽路徑來解析為特定資料行。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.

注意

當資料來源為 DataSetDataViewManagerDataTable 時,您實際上是系結至 DataViewWhen the data source is a DataSet, DataViewManager, or DataTable, you are actually binding to a DataView. 因此,系結的資料列實際上是 @no__t 0 的物件。Consequently, the bound rows are actually DataRowView objects.

當資料來源設定為包含多個 @no__t 0 物件(例如 DataSetDataViewManager)的物件時,需要以句點分隔的導覽路徑。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). 當您系結至物件,且其屬性會傳回其他物件的參考(例如具有傳回其他類別物件之屬性的類別)時,您也可以使用以句點分隔的導覽路徑。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). 例如,下列導覽路徑全都描述有效的資料欄位:For example, the following navigation paths all describe valid data fields:

  • 「大小. 高度」"Size.Height"

  • "Suppliers.CompanyName""Suppliers.CompanyName"

  • "Regions.regionsToCustomers.CustomerFirstName""Regions.regionsToCustomers.CustomerFirstName"

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

路徑的每個成員都可以傳回解析成單一值的屬性(例如整數),或值的清單(例如字串陣列)。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). 雖然路徑中的每個成員都可以是清單或屬性,但最終成員必須解析為屬性。Although each member in the path can be a list or property, the final member must resolve to a property. 每個成員都是以上一個成員為基礎:「大小. 高度」會解析為目前 SizeHeight 屬性;「區域. regionsToCustomers. CustomerFirstName」會解析為目前客戶的名字,其中客戶是目前區域的其中一個客戶。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.

@No__t-0 會傳回值的清單,方法是將一個 DataTable 連結到 DataSet 中的第二個 DataTableA DataRelation returns a list of values by linking one DataTable to a second DataTable in a DataSet. 如果 DataSet 包含 DataRelation 個物件,您可以將資料成員指定為 TableName,後面接著 RelationName,然後 ColumnNameIf the DataSet contains DataRelation objects, you can specify the data member as a TableName followed by a RelationName, and then a ColumnName. 例如,如果名為「供應商」的 @no__t 0 包含名為 "suppliers2products" 的 DataRelation,則資料成員可能是 "suppliers2products"。For example, if the DataTable named "Suppliers" contains a DataRelation named "suppliers2products", the data member could be "Suppliers.suppliers2products.ProductName".

資料來源可以包含一組相關的類別。The data source can consist of a set of related classes. 例如,假設有一組類別目錄日光系統。For example, imagine a set of classes that catalogs solar systems. 名為 System 的類別包含名為 Stars 的屬性,其會傳回 @no__t 2 物件的集合。The class named System contains a property named Stars that returns a collection of Star objects. 每個 @no__t 0 物件都有 Name 和 @no__t 2 屬性,以及會傳回 @no__t 4 物件集合的 Planets 屬性。Each Star object has Name and Mass properties, as well as a Planets property that returns a collection of Planet objects. 在此系統中,每個地球也有 Mass 和 @no__t 1 的屬性。In this system, each planet also has Mass and Name properties. 每個 @no__t 0 物件都有一個 Moons 屬性,它會傳回 @no__t 2 物件的集合,其中每一個都有 Name 和 @no__t 4 屬性。Each Planet object further has a Moons property that returns a collection of Moon objects, each of which also has Name and Mass properties. 如果您指定 System 物件做為資料來源,您可以指定下列任何一個做為資料成員:If you specify a System object as the data source, you can specify any of the following as the data member:

  • "Stars.Name""Stars.Name"

  • "Stars.Mass""Stars.Mass"

  • "Stars.Planets.Name""Stars.Planets.Name"

  • "Stars.Planets.Mass""Stars.Planets.Mass"

  • "Stars.Planets.Moons.Name""Stars.Planets.Moons.Name"

  • "Stars.Planets.Moons.Mass""Stars.Planets.Moons.Mass"

可以是簡單系結功能的控制項是 ControlBindingsCollection 中的 @no__t 0 物件的集合,您可以透過控制項的 @no__t 2 屬性來存取。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. 藉由呼叫 Add 方法,將 Binding 新增至集合,藉此將控制項的屬性系結至物件的屬性(或清單中目前物件的屬性)。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).

您可以簡單地系結至衍生自 @no__t 0 類別的任何物件,例如下列 Windows 控制項:You can simple-bind to any object that derives from the System.Windows.Forms.Control class, for example, the following Windows controls:

注意

只有 ComboBoxCheckedListBox 和 @no__t 3 控制項的 SelectedValue 屬性是簡單系結。Only the SelectedValue property of the ComboBox, CheckedListBox, and ListBox control is simple bound.

@No__t 0 類別是抽象類別,可管理特定資料來源和資料成員的所有 Binding 物件。The BindingManagerBase class is an abstract class that manages all the Binding objects for a particular data source and data member. 衍生自 BindingManagerBase 的類別是 CurrencyManager 和 @no__t 2 類別。Classes that derive from BindingManagerBase are the CurrencyManager and the PropertyManager classes. @No__t-0 的管理方式取決於 Binding 是否為清單系結或屬性系結。How a Binding is managed depends on whether the Binding is a list binding or a property binding. 例如,如果它是清單系結,您可以使用 BindingManagerBase 來指定清單中的 Position;因此,Position 會判斷哪個專案(不在清單中的所有專案中)實際系結至控制項。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. 若要傳回適當的 BindingManagerBase,請使用 BindingContextTo return the appropriate BindingManagerBase, use the BindingContext.

若要將新的資料列加入至系結至相同 DataSource 的一組控制項,請使用 BindingManagerBase 類別的 AddNew 方法。To add a new row to a set of controls bound to the same DataSource, use the AddNew method of the BindingManagerBase class. 請使用 BindingContext 類別的 Item[Object] 屬性來傳回適當的 CurrencyManagerUse the Item[Object] property of the BindingContext class to return the appropriate CurrencyManager. 若要將新資料列的新增設為 escape,請使用 CancelCurrentEdit 方法。To escape the addition of the new row, use the CancelCurrentEdit method.

建構函式

Binding(String, Object, String)

初始化 Binding 類別的新執行個體,其可將所指的控制項屬性簡單繫結至資料來源的指定資料成員。Initializes a new instance of the Binding class that simple-binds the indicated control property to the specified data member of the data source.

Binding(String, Object, String, Boolean)

初始化 Binding 類別的新執行個體,其可將表示的控制項屬性繫結至資料來源的指定資料成員,並選擇性地啟用要套用的格式。Initializes a new instance of the Binding class that binds the indicated control property to the specified data member of the data source, and optionally enables formatting to be applied.

Binding(String, Object, String, Boolean, DataSourceUpdateMode)

初始化 Binding 類別的新執行個體,其可將指定的控制項屬性繫結至指定資料來源的指定資料成員。Initializes a new instance of the Binding class that binds the specified control property to the specified data member of the specified data source. 選擇性地啟用格式,並根據指定的更新設定將值散佈至資料來源。Optionally enables formatting and propagates values to the data source based on the specified update setting.

Binding(String, Object, String, Boolean, DataSourceUpdateMode, Object)

初始化 Binding 類別的新執行個體,其可將指定的控制項屬性繫結至指定之資料來源的指定資料成員。Initializes a new instance of the Binding class that binds the indicated control property to the specified data member of the specified data source. 選擇性地啟用格式、根據指定的更新設定將值散佈至資料來源,並當從資料來源傳回 DBNull 時將屬性設為指定的值。Optionally enables formatting, propagates values to the data source based on the specified update setting, and sets the property to the specified value when a DBNull is returned from the data source.

Binding(String, Object, String, Boolean, DataSourceUpdateMode, Object, String)

初始化 Binding 類別的新執行個體,其可將指定的控制項屬性繫結至指定資料來源的指定資料成員。Initializes a new instance of the Binding class that binds the specified control property to the specified data member of the specified data source. 選擇性地啟用包含指定格式字串的格式、根據指定的更新設定將值散佈至資料來源,並且在從資料來源傳回 DBNull 時將屬性設定為指定的值。Optionally enables formatting with the specified format string; propagates values to the data source based on the specified update setting; and sets the property to the specified value when a DBNull is returned from the data source.

Binding(String, Object, String, Boolean, DataSourceUpdateMode, Object, String, IFormatProvider)

初始化 Binding 類別的新執行個體,其可將指定的控制項屬性繫結至指定資料來源的指定資料成員。Initializes a new instance of the Binding class with the specified control property to the specified data member of the specified data source. 使用指定的格式字串選擇性地啟用格式;根據指定的更新設定將值散佈至資料來源;使用指定的格式字串啟用格式;當從資料來源傳回 DBNull 時將屬性設為指定的值,並設定指定的格式提供者。Optionally enables formatting with the specified format string; propagates values to the data source based on the specified update setting; enables formatting with the specified format string; sets the property to the specified value when a DBNull is returned from the data source; and sets the specified format provider.

屬性

BindableComponent

取得與 Binding 有關聯的控制項。Gets the control the Binding is associated with.

BindingManagerBase

取得這個 BindingManagerBaseBindingGets the BindingManagerBase for this Binding.

BindingMemberInfo

根據 Binding 建構函式中的 dataMember 參數,取得包含這個繫結之相關資訊的物件。Gets an object that contains information about this binding based on the dataMember parameter in the Binding constructor.

Control

取得繫結所屬的控制項。Gets the control that the binding belongs to.

ControlUpdateMode

取得或設定資料來源的變更何時送到已繫結的控制項屬性的值。Gets or sets when changes to the data source are propagated to the bound control property.

DataSource

取得這個繫結的資料來源。Gets the data source for this binding.

DataSourceNullValue

如果控制項值為 null 或空白,則取得或設定要儲存在資料來源中的值。Gets or sets the value to be stored in the data source if the control value is null or empty.

DataSourceUpdateMode

取得或設定值,此值表示何時將繫結控制屬性填入到資料來源中。Gets or sets a value that indicates when changes to the bound control property are propagated to the data source.

FormatInfo

取得或設定提供自訂格式化行為的 IFormatProviderGets or sets the IFormatProvider that provides custom formatting behavior.

FormatString

取得或設定格式規範字元,表示要如何顯示值。Gets or sets the format specifier characters that indicate how a value is to be displayed.

FormattingEnabled

取得或設定值,指出控制項屬性資料是否會套用類型轉換和格式。Gets or sets a value indicating whether type conversion and formatting is applied to the control property data.

IsBinding

取得值,指出繫結是否在作用中。Gets a value indicating whether the binding is active.

NullValue

取得或設定當資料來源包含 Object 值時要設定成控制項屬性的 DBNullGets or sets the Object to be set as the control property when the data source contains a DBNull value.

PropertyName

取得控制項的資料繫結屬性名稱。Gets the name of the control's data-bound property.

方法

Equals(Object)

判斷指定的物件是否等於目前的物件。Determines whether the specified object is equal to the current object.

(繼承來源 Object)
GetHashCode()

作為預設雜湊函數。Serves as the default hash function.

(繼承來源 Object)
GetType()

取得目前執行個體的 TypeGets the Type of the current instance.

(繼承來源 Object)
MemberwiseClone()

建立目前 Object 的淺層複製。Creates a shallow copy of the current Object.

(繼承來源 Object)
OnBindingComplete(BindingCompleteEventArgs)

引發 BindingComplete 事件。Raises the BindingComplete event.

OnFormat(ConvertEventArgs)

引發 Format 事件。Raises the Format event.

OnParse(ConvertEventArgs)

引發 Parse 事件。Raises the Parse event.

ReadValue()

將控制項屬性設定為從資料來源讀取的值。Sets the control property to the value read from the data source.

ToString()

傳回代表目前物件的字串。Returns a string that represents the current object.

(繼承來源 Object)
WriteValue()

從控制項屬性讀取目前的值,並將它寫入資料來源中。Reads the current value from the control property and writes it to the data source.

事件

BindingComplete

發生於 FormattingEnabled 屬性設定為 true 且繫結作業完成時,例如將資料從控制項推入資料來源時,反之亦然。Occurs when the FormattingEnabled property is set to true and a binding operation is complete, such as when data is pushed from the control to the data source or vice versa.

Format

發生於控制項屬性繫結至資料值時。Occurs when the property of a control is bound to a data value.

Parse

發生於資料繫結控制項的值變更時。Occurs when the value of a data-bound control changes.

適用於

另請參閱