|
Il presente articolo è stato tradotto automaticamente. Passare il puntatore sulle frasi nell'articolo per visualizzare il testo originale. Ulteriori informazioni.
|
Traduzione
Originale
|
Delegato KeyPressEventHandler
.NET Framework 4.5
Spazio dei nomi: System.Windows.Forms
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
Parametri
- sender
- Tipo: System.Object
Il database di origine.
- e
- Tipo: System.Windows.Forms.KeyPressEventArgs
In KeyPressEventArgs contenente i dati degli eventi.
Imports System Imports System.Windows.Forms Public Class Form1 Inherits Form Public Sub New() ' Create a TextBox control. Dim tb As New TextBox() Me.Controls.Add(tb) AddHandler tb.KeyPress, AddressOf keypressed End Sub 'New Private Sub keypressed(ByVal o As [Object], ByVal e As KeyPressEventArgs) ' The keypressed method uses the KeyChar property to check ' whether the ENTER key is pressed. ' If the ENTER key is pressed, the Handled property is set to true, ' to indicate the event is handled. If e.KeyChar = Microsoft.VisualBasic.ChrW(Keys.Return) Then e.Handled = True End If End Sub 'keypressed Public Shared Sub Main() Application.Run(New Form1()) End Sub 'Main End Class 'Form1
using System; using System.Windows.Forms; public class Form1: Form { public Form1() { // Create a TextBox control. TextBox tb = new TextBox(); this.Controls.Add(tb); tb.KeyPress += new KeyPressEventHandler(keypressed); } private void keypressed(Object o, KeyPressEventArgs e) { // The keypressed method uses the KeyChar property to check // whether the ENTER key is pressed. // If the ENTER key is pressed, the Handled property is set to true, // to indicate the event is handled. if (e.KeyChar == (char)Keys.Return) { e.Handled = true; } } public static void Main() { Application.Run(new Form1()); } }
#using <System.dll> #using <System.Drawing.dll> #using <System.Windows.Forms.dll> using namespace System; using namespace System::Windows::Forms; public ref class Form1: public Form { public: Form1() { // Create a TextBox control. TextBox^ tb = gcnew TextBox; this->Controls->Add( tb ); tb->KeyPress += gcnew KeyPressEventHandler( this, &Form1::keypressed ); } private: void keypressed( Object^ /*o*/, KeyPressEventArgs^ e ) { // The keypressed method uses the KeyChar property to check // whether the ENTER key is pressed. // If the ENTER key is pressed, the Handled property is set to true, // to indicate the event is handled. if ( e->KeyChar == (char)13 ) e->Handled = true; } }; int main() { Application::Run( gcnew Form1 ); }
' Boolean flag used to determine when a character other than a number is entered. Private nonNumberEntered As Boolean = False ' Handle the KeyDown event to determine the type of character entered into the control. Private Sub textBox1_KeyDown(sender As Object, e As System.Windows.Forms.KeyEventArgs) _ Handles textBox1.KeyDown ' Initialize the flag to false. nonNumberEntered = False ' Determine whether the keystroke is a number from the top of the keyboard. If e.KeyCode < Keys.D0 OrElse e.KeyCode > Keys.D9 Then ' Determine whether the keystroke is a number from the keypad. If e.KeyCode < Keys.NumPad0 OrElse e.KeyCode > Keys.NumPad9 Then ' Determine whether the keystroke is a backspace. If e.KeyCode <> Keys.Back Then ' A non-numerical keystroke was pressed. ' Set the flag to true and evaluate in KeyPress event. nonNumberEntered = True End If End If End If 'If shift key was pressed, it's not a number. If Control.ModifierKeys = Keys.Shift Then nonNumberEntered = true End If End Sub 'textBox1_KeyDown ' This event occurs after the KeyDown event and can be used ' to prevent characters from entering the control. Private Sub textBox1_KeyPress(sender As Object, e As System.Windows.Forms.KeyPressEventArgs) _ Handles textBox1.KeyPress ' Check for the flag being set in the KeyDown event. If nonNumberEntered = True Then ' Stop the character from being entered into the control since it is non-numerical. e.Handled = True End If End Sub 'textBox1_KeyPress
// Boolean flag used to determine when a character other than a number is entered.
private bool nonNumberEntered = false;
// Handle the KeyDown event to determine the type of character entered into the control.
private void textBox1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
// Initialize the flag to false.
nonNumberEntered = false;
// Determine whether the keystroke is a number from the top of the keyboard.
if (e.KeyCode < Keys.D0 || e.KeyCode > Keys.D9)
{
// Determine whether the keystroke is a number from the keypad.
if (e.KeyCode < Keys.NumPad0 || e.KeyCode > Keys.NumPad9)
{
// Determine whether the keystroke is a backspace.
if(e.KeyCode != Keys.Back)
{
// A non-numerical keystroke was pressed.
// Set the flag to true and evaluate in KeyPress event.
nonNumberEntered = true;
}
}
}
//If shift key was pressed, it's not a number.
if (Control.ModifierKeys == Keys.Shift) {
nonNumberEntered = true;
}
}
// This event occurs after the KeyDown event and can be used to prevent
// characters from entering the control.
private void textBox1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
// Check for the flag being set in the KeyDown event.
if (nonNumberEntered == true)
{
// Stop the character from being entered into the control since it is non-numerical.
e.Handled = true;
}
}
// Boolean flag used to determine when a character other than a number is entered. private: bool nonNumberEntered; // Handle the KeyDown event to determine the type of character entered into the control. void textBox1_KeyDown( Object^ /*sender*/, System::Windows::Forms::KeyEventArgs^ e ) { // Initialize the flag to false. nonNumberEntered = false; // Determine whether the keystroke is a number from the top of the keyboard. if ( e->KeyCode < Keys::D0 || e->KeyCode > Keys::D9 ) { // Determine whether the keystroke is a number from the keypad. if ( e->KeyCode < Keys::NumPad0 || e->KeyCode > Keys::NumPad9 ) { // Determine whether the keystroke is a backspace. if ( e->KeyCode != Keys::Back ) { // A non-numerical keystroke was pressed. // Set the flag to true and evaluate in KeyPress event. nonNumberEntered = true; } } } //If shift key was pressed, it's not a number. if (Control::ModifierKeys == Keys::Shift) { nonNumberEntered = true; } } // This event occurs after the KeyDown event and can be used to prevent // characters from entering the control. void textBox1_KeyPress( Object^ /*sender*/, System::Windows::Forms::KeyPressEventArgs^ e ) { // Check for the flag being set in the KeyDown event. if ( nonNumberEntered == true ) { // Stop the character from being entered into the control since it is non-numerical. e->Handled = true; } }
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (ruoli di base del server non supportati), Windows Server 2008 R2 (ruoli di base del server supportati con SP1 o versione successiva, Itanium non supportato)
.NET Framework non supporta tutte le versioni di ciascuna piattaforma. Per un elenco delle versioni supportate, vedere Requisiti di sistema di .NET Framework.
