HelpEventHandler Délégué
Définition
Important
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Représente la méthode qui gérera l'événement HelpRequested d'un Control.
public delegate void HelpEventHandler(System::Object ^ sender, HelpEventArgs ^ hlpevent);
public delegate void HelpEventHandler(object sender, HelpEventArgs hlpevent);
public delegate void HelpEventHandler(object? sender, HelpEventArgs hlpevent);
type HelpEventHandler = delegate of obj * HelpEventArgs -> unit
Public Delegate Sub HelpEventHandler(sender As Object, hlpevent As HelpEventArgs)
Paramètres
- sender
- Object
Source de l'événement.
- hlpevent
- HelpEventArgs
HelpEventArgs qui contient les données d’événement.
Exemples
L’exemple suivant illustre la gestion de l’événement pour afficher le HelpRequested contenu d’aide personnalisé sur un formulaire contenant quatre champs d’adresse. L’événement HelpRequested est déclenché en appuyant sur la touche F1 avec le focus dans un champ d’adresse, ou en utilisant le bouton Aide contextuelle et en cliquant sur le curseur Aide sur un champ d’adresse. La Handled propriété a la valeur true pour indiquer que l’événement HelpRequested
est géré. L’exemple montre également le stockage du texte d’aide dans la Control.Tag propriété .
#using <System.dll>
#using <System.Windows.Forms.dll>
#using <System.Drawing.dll>
using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;
public ref class Form1: public System::Windows::Forms::Form
{
private:
System::Windows::Forms::TextBox^ addressTextBox;
System::Windows::Forms::Label ^ label2;
System::Windows::Forms::TextBox^ cityTextBox;
System::Windows::Forms::Label ^ label3;
System::Windows::Forms::TextBox^ stateTextBox;
System::Windows::Forms::TextBox^ zipTextBox;
System::Windows::Forms::Label ^ helpLabel;
public:
Form1()
{
this->addressTextBox = gcnew System::Windows::Forms::TextBox;
this->helpLabel = gcnew System::Windows::Forms::Label;
this->label2 = gcnew System::Windows::Forms::Label;
this->cityTextBox = gcnew System::Windows::Forms::TextBox;
this->label3 = gcnew System::Windows::Forms::Label;
this->stateTextBox = gcnew System::Windows::Forms::TextBox;
this->zipTextBox = gcnew System::Windows::Forms::TextBox;
// Help Label
this->helpLabel->BorderStyle = System::Windows::Forms::BorderStyle::Fixed3D;
this->helpLabel->Location = System::Drawing::Point( 8, 80 );
this->helpLabel->Size = System::Drawing::Size( 272, 72 );
this->helpLabel->Text = "Click on any control to give it focus, and then press F1 to display help for that control. Alternately, you can click the help button at the top of the dialog and then click on a control.";
// Address Label
this->label2->Location = System::Drawing::Point( 16, 8 );
this->label2->Size = System::Drawing::Size( 100, 16 );
this->label2->Text = "Address:";
// Comma Label
this->label3->Location = System::Drawing::Point( 136, 56 );
this->label3->Size = System::Drawing::Size( 16, 16 );
this->label3->Text = ", ";
// Address TextBox
this->addressTextBox->Location = System::Drawing::Point( 16, 24 );
this->addressTextBox->Size = System::Drawing::Size( 264, 20 );
this->addressTextBox->TabIndex = 0;
this->addressTextBox->Tag = "Enter the street address in this text box.";
this->addressTextBox->Text = "";
this->addressTextBox->HelpRequested += gcnew System::Windows::Forms::HelpEventHandler( this, &Form1::textBox_HelpRequested );
// City TextBox
this->cityTextBox->Location = System::Drawing::Point( 16, 48 );
this->cityTextBox->Size = System::Drawing::Size( 120, 20 );
this->cityTextBox->TabIndex = 3;
this->cityTextBox->Tag = "Enter the city here.";
this->cityTextBox->Text = "";
this->cityTextBox->HelpRequested += gcnew System::Windows::Forms::HelpEventHandler( this, &Form1::textBox_HelpRequested );
// State TextBox
this->stateTextBox->Location = System::Drawing::Point( 152, 48 );
this->stateTextBox->MaxLength = 2;
this->stateTextBox->Size = System::Drawing::Size( 32, 20 );
this->stateTextBox->TabIndex = 5;
this->stateTextBox->Tag = "Enter the state in this text box.";
this->stateTextBox->Text = "";
this->stateTextBox->HelpRequested += gcnew System::Windows::Forms::HelpEventHandler( this, &Form1::textBox_HelpRequested );
// Zip TextBox
this->zipTextBox->Location = System::Drawing::Point( 192, 48 );
this->zipTextBox->Name = "zipTextBox";
this->zipTextBox->Size = System::Drawing::Size( 88, 20 );
this->zipTextBox->TabIndex = 6;
this->zipTextBox->Tag = "Enter the zip code here.";
this->zipTextBox->Text = "";
this->zipTextBox->HelpRequested += gcnew System::Windows::Forms::HelpEventHandler( this, &Form1::textBox_HelpRequested );
// Set up how the form should be displayed and add the controls to the form.
this->ClientSize = System::Drawing::Size( 292, 160 );
array<System::Windows::Forms::Control^>^temp0 = {this->zipTextBox,this->stateTextBox,this->label3,this->cityTextBox,this->label2,this->helpLabel,this->addressTextBox};
this->Controls->AddRange( temp0 );
this->FormBorderStyle = System::Windows::Forms::FormBorderStyle::FixedDialog;
this->HelpButton = true;
this->MaximizeBox = false;
this->MinimizeBox = false;
this->Text = "Help Event Demonstration";
}
private:
void textBox_HelpRequested( Object^ sender, System::Windows::Forms::HelpEventArgs^ hlpevent )
{
// This event is raised when the F1 key is pressed or the
// Help cursor is clicked on any of the address fields.
// The Help text for the field is in the control's
// Tag property. It is retrieved and displayed in the label.
Control^ requestingControl = dynamic_cast<Control^>(sender);
helpLabel->Text = dynamic_cast<String^>(requestingControl->Tag);
hlpevent->Handled = true;
}
};
[STAThread]
int main()
{
Application::Run( gcnew Form1 );
}
using System;
using System.Drawing;
using System.Windows.Forms;
public class Form1 : System.Windows.Forms.Form
{
private System.Windows.Forms.TextBox addressTextBox;
private System.Windows.Forms.Label label2;
private System.Windows.Forms.TextBox cityTextBox;
private System.Windows.Forms.Label label3;
private System.Windows.Forms.TextBox stateTextBox;
private System.Windows.Forms.TextBox zipTextBox;
private System.Windows.Forms.Label helpLabel;
[STAThread]
static void Main()
{
Application.Run(new Form1());
}
public Form1()
{
this.addressTextBox = new System.Windows.Forms.TextBox();
this.helpLabel = new System.Windows.Forms.Label();
this.label2 = new System.Windows.Forms.Label();
this.cityTextBox = new System.Windows.Forms.TextBox();
this.label3 = new System.Windows.Forms.Label();
this.stateTextBox = new System.Windows.Forms.TextBox();
this.zipTextBox = new System.Windows.Forms.TextBox();
// Help Label
this.helpLabel.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
this.helpLabel.Location = new System.Drawing.Point(8, 80);
this.helpLabel.Size = new System.Drawing.Size(272, 72);
this.helpLabel.Text = "Click on any control to give it focus, and then " +
"press F1 to display help for that control. Alternately, you can " +
"click the help button at the top of the dialog and then click on a control.";
// Address Label
this.label2.Location = new System.Drawing.Point(16, 8);
this.label2.Size = new System.Drawing.Size(100, 16);
this.label2.Text = "Address:";
// Comma Label
this.label3.Location = new System.Drawing.Point(136, 56);
this.label3.Size = new System.Drawing.Size(16, 16);
this.label3.Text = ",";
// Address TextBox
this.addressTextBox.Location = new System.Drawing.Point(16, 24);
this.addressTextBox.Size = new System.Drawing.Size(264, 20);
this.addressTextBox.TabIndex = 0;
this.addressTextBox.Tag = "Enter the street address in this text box.";
this.addressTextBox.Text = "";
this.addressTextBox.HelpRequested += new System.Windows.Forms.HelpEventHandler(this.textBox_HelpRequested);
// City TextBox
this.cityTextBox.Location = new System.Drawing.Point(16, 48);
this.cityTextBox.Size = new System.Drawing.Size(120, 20);
this.cityTextBox.TabIndex = 3;
this.cityTextBox.Tag = "Enter the city here.";
this.cityTextBox.Text = "";
this.cityTextBox.HelpRequested += new System.Windows.Forms.HelpEventHandler(this.textBox_HelpRequested);
// State TextBox
this.stateTextBox.Location = new System.Drawing.Point(152, 48);
this.stateTextBox.MaxLength = 2;
this.stateTextBox.Size = new System.Drawing.Size(32, 20);
this.stateTextBox.TabIndex = 5;
this.stateTextBox.Tag = "Enter the state in this text box.";
this.stateTextBox.Text = "";
this.stateTextBox.HelpRequested += new System.Windows.Forms.HelpEventHandler(this.textBox_HelpRequested);
// Zip TextBox
this.zipTextBox.Location = new System.Drawing.Point(192, 48);
this.zipTextBox.Name = "zipTextBox";
this.zipTextBox.Size = new System.Drawing.Size(88, 20);
this.zipTextBox.TabIndex = 6;
this.zipTextBox.Tag = "Enter the zip code here.";
this.zipTextBox.Text = "";
this.zipTextBox.HelpRequested += new System.Windows.Forms.HelpEventHandler(this.textBox_HelpRequested);
// Set up how the form should be displayed and add the controls to the form.
this.ClientSize = new System.Drawing.Size(292, 160);
this.Controls.AddRange(new System.Windows.Forms.Control[] { this.zipTextBox,
this.stateTextBox, this.label3, this.cityTextBox,
this.label2, this.helpLabel, this.addressTextBox});
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;
this.HelpButton = true;
this.MaximizeBox = false;
this.MinimizeBox = false;
this.Text = "Help Event Demonstration";
}
private void textBox_HelpRequested(object sender, System.Windows.Forms.HelpEventArgs hlpevent)
{
// This event is raised when the F1 key is pressed or the
// Help cursor is clicked on any of the address fields.
// The Help text for the field is in the control's
// Tag property. It is retrieved and displayed in the label.
Control requestingControl = (Control)sender;
helpLabel.Text = (string)requestingControl.Tag;
hlpevent.Handled = true;
}
}
Imports System.Drawing
Imports System.Windows.Forms
Public Class Form1
Inherits System.Windows.Forms.Form
Private WithEvents addressTextBox As System.Windows.Forms.TextBox
Private WithEvents label2 As System.Windows.Forms.Label
Private WithEvents cityTextBox As System.Windows.Forms.TextBox
Private WithEvents label3 As System.Windows.Forms.Label
Private WithEvents stateTextBox As System.Windows.Forms.TextBox
Private WithEvents zipTextBox As System.Windows.Forms.TextBox
Private WithEvents helpLabel As System.Windows.Forms.Label
<STAThread()> _
Shared Sub Main()
Application.Run(New Form1)
End Sub
Public Sub New()
Me.addressTextBox = New System.Windows.Forms.TextBox
Me.helpLabel = New System.Windows.Forms.Label
Me.label2 = New System.Windows.Forms.Label
Me.cityTextBox = New System.Windows.Forms.TextBox
Me.label3 = New System.Windows.Forms.Label
Me.stateTextBox = New System.Windows.Forms.TextBox
Me.zipTextBox = New System.Windows.Forms.TextBox
' Help Label
Me.helpLabel.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D
Me.helpLabel.Location = New System.Drawing.Point(8, 80)
Me.helpLabel.Size = New System.Drawing.Size(272, 72)
Me.helpLabel.Text = "Click on any control to give it focus, and then " & _
"press F1 to display help for that" + " control. Alternately, you can " & _
"click the help button at the top of the dialog and then click on a control."
' Address Label
Me.label2.Location = New System.Drawing.Point(16, 8)
Me.label2.Size = New System.Drawing.Size(100, 16)
Me.label2.Text = "Address:"
' Comma Label
Me.label3.Location = New System.Drawing.Point(136, 56)
Me.label3.Size = New System.Drawing.Size(16, 16)
Me.label3.Text = ","
' Address TextBox
Me.addressTextBox.Location = New System.Drawing.Point(16, 24)
Me.addressTextBox.Size = New System.Drawing.Size(264, 20)
Me.addressTextBox.TabIndex = 0
Me.addressTextBox.Tag = "Enter the stree address in this text box."
Me.addressTextBox.Text = ""
' City TextBox
Me.cityTextBox.Location = New System.Drawing.Point(16, 48)
Me.cityTextBox.Size = New System.Drawing.Size(120, 20)
Me.cityTextBox.TabIndex = 3
Me.cityTextBox.Tag = "Enter the city here."
Me.cityTextBox.Text = ""
' State TextBox
Me.stateTextBox.Location = New System.Drawing.Point(152, 48)
Me.stateTextBox.MaxLength = 2
Me.stateTextBox.Size = New System.Drawing.Size(32, 20)
Me.stateTextBox.TabIndex = 5
Me.stateTextBox.Tag = "Enter the state in this text box."
Me.stateTextBox.Text = ""
' Zip TextBox
Me.zipTextBox.Location = New System.Drawing.Point(192, 48)
Me.zipTextBox.Size = New System.Drawing.Size(88, 20)
Me.zipTextBox.TabIndex = 6
Me.zipTextBox.Tag = "Enter the zip code here."
Me.zipTextBox.Text = ""
' Set up how the form should be displayed and add the controls to the form.
Me.ClientSize = New System.Drawing.Size(292, 160)
Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.zipTextBox, _
Me.stateTextBox, Me.label3, Me.cityTextBox, _
Me.label2, Me.helpLabel, Me.addressTextBox})
Me.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog
Me.HelpButton = True
Me.MaximizeBox = False
Me.MinimizeBox = False
Me.Text = "Help Event Demonstration"
End Sub
Private Sub textBox_HelpRequested(ByVal sender As Object, ByVal hlpevent As System.Windows.Forms.HelpEventArgs) Handles addressTextBox.HelpRequested, cityTextBox.HelpRequested, stateTextBox.HelpRequested, zipTextBox.HelpRequested
' This event is raised when the F1 key is pressed or the
' Help cursor is clicked on any of the address fields.
' The Help text for the field is in the control's
' Tag property. It is retrieved and displayed in the label.
Dim requestingControl As Control = CType(sender, Control)
helpLabel.Text = CStr(requestingControl.Tag)
hlpevent.Handled = True
End Sub
End Class
Remarques
Lorsque vous créez un délégué HelpEventHandler, vous identifiez la méthode qui gérera l'événement. Pour associer l'événement au gestionnaire d'événements, ajoutez une instance du délégué à l'événement. Le gestionnaire d'événements est appelé chaque fois qu'un événement se produit, sauf si vous supprimez le délégué. Pour plus d’informations sur la gestion des événements avec des délégués, consultez Gestion et déclenchement d’événements.
Méthodes d’extension
GetMethodInfo(Delegate) |
Obtient un objet qui représente la méthode représentée par le délégué spécifié. |