Procedura: associare dati al controllo MaskedTextBox

Articolo
09/12/2008

Aggiornamento: novembre 2007

È possibile associare dati a un controllo MaskedTextBox in maniera analoga a quanto avviene per qualsiasi altro controllo Windows Form. Tuttavia, se il formato dei dati all'interno del database non corrisponde a quello previsto dalla definizione della maschera, è necessario riformattare i dati. Nella routine riportata di seguito viene illustrato come eseguire questa operazione utilizzando gli eventi Format e Parse della classe Binding per visualizzare campi di database distinti per i numeri telefonici e i numeri interni come un singolo campo modificabile.

Per la routine riportata di seguito è necessario l'accesso a un database SQL Server in cui sia installato il database di esempio Northwind.

Per associare dati a un controllo MaskedTextBox

Creare un nuovo progetto Windows Form.
Trascinare due controlli TextBox nel form; denominarli FirstName e LastName.
Trascinare un controllo MaskedTextBox sul form; denominarlo PhoneMask.
Impostare la proprietà Mask di PhoneMask su (000) 000-0000 x9999.
Aggiungere i seguenti elementi importati dello spazio dei nomi al form:
```
using System.Data.SqlClient;
```
```
Imports System.Data.SqlClient
```

Fare clic con il pulsante destro del mouse sul form, quindi scegliere Visualizza codice. Inserire il codice in un punto della classe del form.

Binding currentBinding, phoneBinding;
DataSet employeesTable = new DataSet();
SqlConnection sc;
SqlDataAdapter dataConnect;

private void Form1_Load(object sender, EventArgs e)
{
    DoMaskBinding();
}

private void DoMaskBinding()
{
    try
    {
        sc = new SqlConnection("Data Source=CLIENTUE;Initial Catalog=NORTHWIND;Integrated Security=SSPI");
        sc.Open();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
        return;
    }

    dataConnect = new SqlDataAdapter("SELECT * FROM Employees", sc);
    dataConnect.Fill(employeesTable, "Employees");

    // Now bind MaskedTextBox to appropriate field. Note that we must create the Binding objects
    // before adding them to the control - otherwise, we won't get a Format event on the 
    // initial load. 
    try
    {
        currentBinding = new Binding("Text", employeesTable, "Employees.FirstName");
        firstName.DataBindings.Add(currentBinding);

        currentBinding = new Binding("Text", employeesTable, "Employees.LastName");
        lastName.DataBindings.Add(currentBinding);

        phoneBinding =new Binding("Text", employeesTable, "Employees.HomePhone");
        // We must add the event handlers before we bind, or the Format event will not get called
        // for the first record.
        phoneBinding.Format += new ConvertEventHandler(phoneBinding_Format);
        phoneBinding.Parse += new ConvertEventHandler(phoneBinding_Parse);
        phoneMask.DataBindings.Add(phoneBinding);
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
        return;
    }
}

Dim WithEvents CurrentBinding, PhoneBinding As Binding
Dim EmployeesTable As New DataSet()
Dim sc As SqlConnection
Dim DataConnect As SqlDataAdapter

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    DoMaskedBinding()
End Sub

Private Sub DoMaskedBinding()
    Try
        sc = New SqlConnection("Data Source=SERVERNAME;Initial Catalog=NORTHWIND;Integrated Security=SSPI")
        sc.Open()
    Catch ex As Exception
        MessageBox.Show(ex.Message)
        Exit Sub
    End Try

    DataConnect = New SqlDataAdapter("SELECT * FROM Employees", sc)
    DataConnect.Fill(EmployeesTable, "Employees")

    ' Now bind MaskedTextBox to appropriate field. Note that we must create the Binding objects
    ' before adding them to the control - otherwise, we won't get a Format event on the 
    ' initial load.
    Try
        CurrentBinding = New Binding("Text", EmployeesTable, "Employees.FirstName")
        firstName.DataBindings.Add(CurrentBinding)
        CurrentBinding = New Binding("Text", EmployeesTable, "Employees.LastName")
        lastName.DataBindings.Add(CurrentBinding)
        PhoneBinding = New Binding("Text", EmployeesTable, "Employees.HomePhone")
        PhoneMask.DataBindings.Add(PhoneBinding)
    Catch ex As Exception
        MessageBox.Show(ex.Message)
        Application.Exit()
    End Try
End Sub

Aggiungere gestori eventi per gli eventi Format e Parse per combinare e separare i campi PhoneNumber e Extension dalla classe DataSet associata.

private void phoneBinding_Format(Object sender, ConvertEventArgs e)
{
    String ext;

    DataRowView currentRow = (DataRowView)BindingContext[employeesTable, "Employees"].Current;
    if (currentRow["Extension"] == null) 
    {
        ext = "";
    } else 
    {
        ext = currentRow["Extension"].ToString();
    }

    e.Value = e.Value.ToString().Trim() + " x" + ext;
}

private void phoneBinding_Parse(Object sender, ConvertEventArgs e)
{
    String phoneNumberAndExt = e.Value.ToString();

    int extIndex = phoneNumberAndExt.IndexOf("x");
    String ext = phoneNumberAndExt.Substring(extIndex).Trim();
    String phoneNumber = phoneNumberAndExt.Substring(0, extIndex).Trim();

    //Get the current binding object, and set the new extension manually. 
    DataRowView currentRow = (DataRowView)BindingContext[employeesTable, "Employees"].Current;
    // Remove the "x" from the extension.
    currentRow["Extension"] = ext.Substring(1);

    //Return the phone number.
    e.Value = phoneNumber;
}

Private Sub PhoneBinding_Format(ByVal sender As Object, ByVal e As ConvertEventArgs) Handles PhoneBinding.Format
    Dim Ext As String

    Dim CurrentRow As DataRowView = CType(Me.BindingContext(EmployeesTable, "Employees").Current, DataRowView)
    If (CurrentRow("Extension") Is Nothing) Then
        Ext = ""
    Else
        Ext = CurrentRow("Extension").ToString()
    End If

    e.Value = e.Value.ToString().Trim() & " x" & Ext
End Sub

Private Sub PhoneBinding_Parse(ByVal sender As Object, ByVal e As ConvertEventArgs) Handles PhoneBinding.Parse
    Dim PhoneNumberAndExt As String = e.Value.ToString()

    Dim ExtIndex As Integer = PhoneNumberAndExt.IndexOf("x")
    Dim Ext As String = PhoneNumberAndExt.Substring(ExtIndex).Trim()
    Dim PhoneNumber As String = PhoneNumberAndExt.Substring(0, ExtIndex).Trim()

    ' Get the current binding object, and set the new extension manually. 
    Dim CurrentRow As DataRowView = CType(Me.BindingContext(EmployeesTable, "Employees").Current, DataRowView)
    ' Remove the "x" from the extension.
    CurrentRow("Extension") = CObj(Ext.Substring(1))

    ' Return the phone number.
    e.Value = PhoneNumber
End Sub

Aggiungere due controlli Button nel form. Denominarli previousButton e nextButton. Fare doppio clic su ciascun pulsante per aggiungere un gestore eventi Click e inserire dati nei gestori eventi come mostrato nell'esempio di codice riportato di seguito.

private void previousButton_Click(object sender, EventArgs e)
{
    BindingContext[employeesTable, "Employees"].Position = BindingContext[employeesTable, "Employees"].Position - 1;
}

private void nextButton_Click(object sender, EventArgs e)
{
    BindingContext[employeesTable, "Employees"].Position = BindingContext[employeesTable, "Employees"].Position + 1;
}

Private Sub PreviousButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PreviousButton.Click
    Me.BindingContext(EmployeesTable, "Employees").Position = Me.BindingContext(EmployeesTable, "Employees").Position - 1
End Sub

Private Sub NextButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles NextButton.Click
    Me.BindingContext(EmployeesTable, "Employees").Position = Me.BindingContext(EmployeesTable, "Employees").Position + 1
End Sub

Eseguire l'esempio. Modificare i dati e utilizzare i pulsanti Previous e Next per verificare la persistenza dei dati nella classe DataSet.

Esempio

L'esempio di codice riportato di seguito rappresenta il listato di codice completo risultante dal completamento della routine precedente.

Imports System.Data.SqlClient

Public Class Form1
    Dim WithEvents CurrentBinding, PhoneBinding As Binding
    Dim EmployeesTable As New DataSet()
    Dim sc As SqlConnection
    Dim DataConnect As SqlDataAdapter

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        DoMaskedBinding()
    End Sub

    Private Sub DoMaskedBinding()
        Try
            sc = New SqlConnection("Data Source=localhost;Initial Catalog=NORTHWIND;Integrated Security=SSPI")
            sc.Open()
        Catch ex As Exception
            MessageBox.Show(ex.Message)
            Application.Exit()
        End Try

        DataConnect = New SqlDataAdapter("SELECT * FROM Employees", sc)
        DataConnect.Fill(EmployeesTable, "Employees")

        ' Now bind MaskedTextBox to appropriate field. Note that we must create the Binding objects
        ' before adding them to the control - otherwise, we won't get a Format event on the 
        ' initial load. 
        Try
            CurrentBinding = New Binding("Text", EmployeesTable, "Employees.FirstName")
            firstName.DataBindings.Add(CurrentBinding)
            CurrentBinding = New Binding("Text", EmployeesTable, "Employees.LastName")
            lastName.DataBindings.Add(CurrentBinding)
            PhoneBinding = New Binding("Text", EmployeesTable, "Employees.HomePhone")
            PhoneMask.DataBindings.Add(PhoneBinding)
        Catch ex As Exception
            MessageBox.Show(ex.Message)
            Application.Exit()
        End Try
    End Sub

    Private Sub PhoneBinding_Format(ByVal sender As Object, ByVal e As ConvertEventArgs) Handles PhoneBinding.Format
        Dim Ext As String

        Dim CurrentRow As DataRowView = CType(Me.BindingContext(EmployeesTable, "Employees").Current, DataRowView)
        If (CurrentRow("Extension") Is Nothing) Then
            Ext = ""
        Else
            Ext = CurrentRow("Extension").ToString()
        End If

        e.Value = e.Value.ToString().Trim() & " x" & Ext
    End Sub

    Private Sub PhoneBinding_Parse(ByVal sender As Object, ByVal e As ConvertEventArgs) Handles PhoneBinding.Parse
        Dim PhoneNumberAndExt As String = e.Value.ToString()

        Dim ExtIndex As Integer = PhoneNumberAndExt.IndexOf("x")
        Dim Ext As String = PhoneNumberAndExt.Substring(ExtIndex).Trim()
        Dim PhoneNumber As String = PhoneNumberAndExt.Substring(0, ExtIndex).Trim()

        ' Get the current binding object, and set the new extension manually. 
        Dim CurrentRow As DataRowView = CType(Me.BindingContext(EmployeesTable, "Employees").Current, DataRowView)
        ' Remove the "x" from the extension.
        CurrentRow("Extension") = CObj(Ext.Substring(1))

        ' Return the phone number.
        e.Value = PhoneNumber
    End Sub

    Private Sub NextButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles NextButton.Click
        Me.BindingContext(EmployeesTable, "Employees").Position = Me.BindingContext(EmployeesTable, "Employees").Position + 1
    End Sub

    Private Sub PreviousButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PreviousButton.Click
        Me.BindingContext(EmployeesTable, "Employees").Position = Me.BindingContext(EmployeesTable, "Employees").Position - 1
    End Sub
End Class

#region Using directives

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

#endregion

namespace MaskedTextBoxDataCSharp
{
    partial class Form1 : Form
    {
        Binding currentBinding, phoneBinding;
        DataSet employeesTable = new DataSet();
        SqlConnection sc;
        SqlDataAdapter dataConnect;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            DoMaskBinding();
        }

        private void DoMaskBinding()
        {
            try
            {
                sc = new SqlConnection("Data Source=localhost;Initial Catalog=NORTHWIND;Integrated Security=SSPI");
                sc.Open();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                return;
            }

            dataConnect = new SqlDataAdapter("SELECT * FROM Employees", sc);
            dataConnect.Fill(employeesTable, "Employees");


            // Now bind MaskedTextBox to appropriate field. Note that we must create the Binding objects
            // before adding them to the control - otherwise, we won't get a Format event on the 
            // initial load. 
            try
            {
                currentBinding = new Binding("Text", employeesTable, "Employees.FirstName");
                firstName.DataBindings.Add(currentBinding);

                currentBinding = new Binding("Text", employeesTable, "Employees.LastName");
                lastName.DataBindings.Add(currentBinding);

                phoneBinding =new Binding("Text", employeesTable, "Employees.HomePhone");
                // We must add the event handlers before we bind, or the Format event will not get called
                // for the first record.
                phoneBinding.Format += new ConvertEventHandler(phoneBinding_Format);
                phoneBinding.Parse += new ConvertEventHandler(phoneBinding_Parse);
                phoneMask.DataBindings.Add(phoneBinding);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                return;
            }
        }

        private void phoneBinding_Format(Object sender, ConvertEventArgs e)
        {
            String ext;

            DataRowView currentRow = (DataRowView)BindingContext[employeesTable, "Employees"].Current;
            if (currentRow["Extension"] == null) 
            {
                ext = "";
            } else 
            {
                ext = currentRow["Extension"].ToString();
            }

            e.Value = e.Value.ToString().Trim() + " x" + ext;
        }

        private void phoneBinding_Parse(Object sender, ConvertEventArgs e)
        {
            String phoneNumberAndExt = e.Value.ToString();

            int extIndex = phoneNumberAndExt.IndexOf("x");
            String ext = phoneNumberAndExt.Substring(extIndex).Trim();
            String phoneNumber = phoneNumberAndExt.Substring(0, extIndex).Trim();

            //Get the current binding object, and set the new extension manually. 
            DataRowView currentRow = (DataRowView)BindingContext[employeesTable, "Employees"].Current;
            // Remove the "x" from the extension.
            currentRow["Extension"] = ext.Substring(1);

            //Return the phone number.
            e.Value = phoneNumber;
        }

        private void previousButton_Click(object sender, EventArgs e)
        {
            BindingContext[employeesTable, "Employees"].Position = BindingContext[employeesTable, "Employees"].Position - 1;
        }

        private void nextButton_Click(object sender, EventArgs e)
        {
            BindingContext[employeesTable, "Employees"].Position = BindingContext[employeesTable, "Employees"].Position + 1;
        }
    }
}

Compilazione del codice

Creare un progetto Visual C# o Visual Basic.
Aggiungere i controlli TextBox e MaskedTextBox al form, come descritto nella routine precedente.
Aprire il file di codice sorgente relativo al form predefinito del progetto.
Sostituire il codice sorgente all'interno del file con il codice della precedente sezione di codice.
Compilare l'applicazione.

Vedere anche

Attività

Procedura dettagliata: utilizzo del controllo MaskedTextBox

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