SystemInformation.MouseWheelScrollLines Propriété

Définition

Obtient le nombre de lignes à faire défiler lors de la rotation de la roulette de la souris.Gets the number of lines to scroll when the mouse wheel is rotated.

public:
 static property int MouseWheelScrollLines { int get(); };
public static int MouseWheelScrollLines { get; }
member this.MouseWheelScrollLines : int
Public Shared ReadOnly Property MouseWheelScrollLines As Integer

Valeur de propriété

Nombre de lignes à faire défiler lors de la rotation de la roulette de la souris, ou -1 si l'option de la souris "Écran par écran" est sélectionnée.The number of lines to scroll on a mouse wheel rotation, or -1 if the "One screen at a time" mouse option is selected.

Exemples

L’exemple de code suivant répertorie toutes les propriétés de la classe SystemInformation dans un ListBox et affiche la valeur actuelle de la propriété dans un TextBox lorsqu’un élément de liste est sélectionné.The following code example lists all properties of the SystemInformation class in a ListBox and displays the current value of the property in a TextBox when a list item selected.

#using <System.Windows.Forms.dll>
#using <System.Drawing.dll>
#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::ComponentModel;
using namespace System::Drawing;
using namespace System::Reflection;
using namespace System::Windows::Forms;
public ref class SystemInfoBrowserForm: public System::Windows::Forms::Form
{
private:
   System::Windows::Forms::ListBox^ listBox1;
   System::Windows::Forms::TextBox^ textBox1;

public:
   SystemInfoBrowserForm()
   {
      this->SuspendLayout();
      InitForm();
      
      // Add each property of the SystemInformation class to the list box.
      Type^ t = System::Windows::Forms::SystemInformation::typeid;
      array<PropertyInfo^>^pi = t->GetProperties();
      for ( int i = 0; i < pi->Length; i++ )
         listBox1->Items->Add( pi[ i ]->Name );
      textBox1->Text = String::Format( "The SystemInformation class has {0} properties.\r\n", pi->Length );
      
      // Configure the list item selected handler for the list box to invoke a 
      // method that displays the value of each property.
      listBox1->SelectedIndexChanged += gcnew EventHandler( this, &SystemInfoBrowserForm::listBox1_SelectedIndexChanged );
      this->ResumeLayout( false );
   }


private:
   void listBox1_SelectedIndexChanged( Object^ /*sender*/, EventArgs^ /*e*/ )
   {
      
      // Return if no list item is selected.
      if ( listBox1->SelectedIndex == -1 )
            return;

      
      // Get the property name from the list item.
      String^ propname = listBox1->Text;
      if ( propname->Equals( "PowerStatus" ) )
      {
         
         // Cycle and display the values of each property of the PowerStatus property.
         textBox1->Text = String::Concat( textBox1->Text, "\r\nThe value of the PowerStatus property is:" );
         Type^ t = System::Windows::Forms::PowerStatus::typeid;
         array<PropertyInfo^>^pi = t->GetProperties();
         for ( int i = 0; i < pi->Length; i++ )
         {
            Object^ propval = pi[ i ]->GetValue( SystemInformation::PowerStatus, nullptr );
            textBox1->Text = String::Format( "{0}\r\n    PowerStatus.{1} is: {2}", textBox1->Text, pi[ i ]->Name, propval );

         }
      }
      else
      {
         
         // Display the value of the selected property of the SystemInformation type.
         Type^ t = System::Windows::Forms::SystemInformation::typeid;
         array<PropertyInfo^>^pi = t->GetProperties();
         PropertyInfo^ prop = nullptr;
         for ( int i = 0; i < pi->Length; i++ )
            if ( pi[ i ]->Name == propname )
            {
               prop = pi[ i ];
               break;
            }
         Object^ propval = prop->GetValue( nullptr, nullptr );
         textBox1->Text = String::Format( "{0}\r\nThe value of the {1} property is: {2}", textBox1->Text, propname, propval );
      }
   }

   void InitForm()
   {
      
      // Initialize the form settings
      this->listBox1 = gcnew System::Windows::Forms::ListBox;
      this->textBox1 = gcnew System::Windows::Forms::TextBox;
      this->listBox1->Anchor = (System::Windows::Forms::AnchorStyles)(System::Windows::Forms::AnchorStyles::Top | System::Windows::Forms::AnchorStyles::Bottom | System::Windows::Forms::AnchorStyles::Left | System::Windows::Forms::AnchorStyles::Right);
      this->listBox1->Location = System::Drawing::Point( 8, 16 );
      this->listBox1->Size = System::Drawing::Size( 172, 496 );
      this->listBox1->TabIndex = 0;
      this->textBox1->Anchor = (System::Windows::Forms::AnchorStyles)(System::Windows::Forms::AnchorStyles::Top | System::Windows::Forms::AnchorStyles::Bottom | System::Windows::Forms::AnchorStyles::Right);
      this->textBox1->Location = System::Drawing::Point( 188, 16 );
      this->textBox1->Multiline = true;
      this->textBox1->ScrollBars = System::Windows::Forms::ScrollBars::Vertical;
      this->textBox1->Size = System::Drawing::Size( 420, 496 );
      this->textBox1->TabIndex = 1;
      this->ClientSize = System::Drawing::Size( 616, 525 );
      this->Controls->Add( this->textBox1 );
      this->Controls->Add( this->listBox1 );
      this->Text = "Select a SystemInformation property to get the value of";
   }

};


[STAThread]
int main()
{
   Application::Run( gcnew SystemInfoBrowserForm );
}

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Reflection;
using System.Windows.Forms;

namespace SystemInfoBrowser
{
    public class SystemInfoBrowserForm : System.Windows.Forms.Form
    {
        private System.Windows.Forms.ListBox listBox1;
        private System.Windows.Forms.TextBox textBox1;        
        
        public SystemInfoBrowserForm()
        {
            this.SuspendLayout();
            InitForm();
            
            // Add each property of the SystemInformation class to the list box.
            Type t = typeof(System.Windows.Forms.SystemInformation);            
            PropertyInfo[] pi = t.GetProperties();            
            for( int i=0; i<pi.Length; i++ )
                listBox1.Items.Add( pi[i].Name );            
            textBox1.Text = "The SystemInformation class has "+pi.Length.ToString()+" properties.\r\n";

            // Configure the list item selected handler for the list box to invoke a 
            // method that displays the value of each property.
            listBox1.SelectedIndexChanged += new EventHandler(listBox1_SelectedIndexChanged);
            this.ResumeLayout(false);
        }
        
        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            // Return if no list item is selected.
            if( listBox1.SelectedIndex == -1 ) return;
            // Get the property name from the list item.
            string propname = listBox1.Text;
            
            if( propname == "PowerStatus" )
            {
                // Cycle and display the values of each property of the PowerStatus property.
                textBox1.Text += "\r\nThe value of the PowerStatus property is:";                                
                Type t = typeof(System.Windows.Forms.PowerStatus);
                PropertyInfo[] pi = t.GetProperties();            
                for( int i=0; i<pi.Length; i++ )
                {
                    object propval = pi[i].GetValue(SystemInformation.PowerStatus, null);            
                    textBox1.Text += "\r\n    PowerStatus."+pi[i].Name+" is: "+propval.ToString();
                }
            }
            else
            {
                // Display the value of the selected property of the SystemInformation type.
                Type t = typeof(System.Windows.Forms.SystemInformation);
                PropertyInfo[] pi = t.GetProperties();            
                PropertyInfo prop = null;
                for( int i=0; i<pi.Length; i++ )
                    if( pi[i].Name == propname )
                    {
                        prop = pi[i];
                        break;           
                    }
                object propval = prop.GetValue(null, null);            
                textBox1.Text += "\r\nThe value of the "+propname+" property is: "+propval.ToString();
            }
        }

        private void InitForm()
        {
            // Initialize the form settings
            this.listBox1 = new System.Windows.Forms.ListBox();
            this.textBox1 = new System.Windows.Forms.TextBox();            
            this.listBox1.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom) 
                | System.Windows.Forms.AnchorStyles.Left) | System.Windows.Forms.AnchorStyles.Right)));
            this.listBox1.Location = new System.Drawing.Point(8, 16);
            this.listBox1.Size = new System.Drawing.Size(172, 496);
            this.listBox1.TabIndex = 0;            
            this.textBox1.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom) 
                | System.Windows.Forms.AnchorStyles.Right)));
            this.textBox1.Location = new System.Drawing.Point(188, 16);
            this.textBox1.Multiline = true;
            this.textBox1.ScrollBars = System.Windows.Forms.ScrollBars.Vertical;           
            this.textBox1.Size = new System.Drawing.Size(420, 496);
            this.textBox1.TabIndex = 1;            
            this.ClientSize = new System.Drawing.Size(616, 525);            
            this.Controls.Add(this.textBox1);
            this.Controls.Add(this.listBox1);            
            this.Text = "Select a SystemInformation property to get the value of";                   
        }

        [STAThread]
        static void Main() 
        {
            Application.Run(new SystemInfoBrowserForm());
        }
    }
}
Imports System.Collections
Imports System.ComponentModel
Imports System.Drawing
Imports System.Reflection
Imports System.Windows.Forms

Public Class SystemInfoBrowserForm
    Inherits System.Windows.Forms.Form
    
    Private listBox1 As System.Windows.Forms.ListBox
    Private textBox1 As System.Windows.Forms.TextBox  
    
    Public Sub New()
        Me.SuspendLayout()
        InitForm()
        
        ' Add each property of the SystemInformation class to the list box.
        Dim t As Type = GetType(System.Windows.Forms.SystemInformation)
        Dim pi As PropertyInfo() = t.GetProperties()
        Dim i As Integer
        For i = 0 To pi.Length - 1
            listBox1.Items.Add(pi(i).Name)
        Next i
        textBox1.Text = "The SystemInformation class has " + pi.Length.ToString() + " properties." + ControlChars.CrLf
        
        ' Configure the list item selected handler for the list box to invoke a 
        ' method that displays the value of each property.
        AddHandler listBox1.SelectedIndexChanged, AddressOf listBox1_SelectedIndexChanged
        
        Me.ResumeLayout(False)
    End Sub    
    
    Private Sub listBox1_SelectedIndexChanged(sender As Object, e As EventArgs)
        ' Return if no list item is selected.
        If listBox1.SelectedIndex = - 1 Then
            Return
        End If         
        ' Get the property name from the list item.
        Dim propname As String = listBox1.Text
        
        If propname = "PowerStatus" Then
            ' Cycle and display the values of each property of the PowerStatus property.
            textBox1.Text += ControlChars.CrLf + "The value of the PowerStatus property is:"
            Dim t As Type = GetType(System.Windows.Forms.PowerStatus)
            Dim pi As PropertyInfo() = t.GetProperties()
            Dim i As Integer
            For i = 0 To pi.Length - 1
                Dim propval As Object = pi(i).GetValue(SystemInformation.PowerStatus, Nothing)
                textBox1.Text += ControlChars.CrLf + "    PowerStatus." + pi(i).Name + " is: " + propval.ToString()
            Next i
        Else
            ' Display the value of the selected property of the SystemInformation type.
            Dim t As Type = GetType(System.Windows.Forms.SystemInformation)
            Dim pi As PropertyInfo() = t.GetProperties()
            Dim prop As PropertyInfo = Nothing
            Dim i As Integer
            For i = 0 To pi.Length - 1
                If pi(i).Name = propname Then
                    prop = pi(i)
                    Exit For
                End If
            Next i
            Dim propval As Object = prop.GetValue(Nothing, Nothing)
            textBox1.Text += ControlChars.CrLf + "The value of the " + propname + " property is: " + propval.ToString()
        End If
    End Sub    
    
    Private Sub InitForm()
        ' Initialize the form settings
        Me.listBox1 = New System.Windows.Forms.ListBox()
        Me.textBox1 = New System.Windows.Forms.TextBox()
        Me.listBox1.Anchor = CType(System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Left Or System.Windows.Forms.AnchorStyles.Right, System.Windows.Forms.AnchorStyles)
        Me.listBox1.Location = New System.Drawing.Point(8, 16)
        Me.listBox1.Size = New System.Drawing.Size(172, 496)
        Me.listBox1.TabIndex = 0
        Me.textBox1.Anchor = CType(System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Right, System.Windows.Forms.AnchorStyles)
        Me.textBox1.Location = New System.Drawing.Point(188, 16)
        Me.textBox1.Multiline = True
        Me.textBox1.ScrollBars = System.Windows.Forms.ScrollBars.Vertical
        Me.textBox1.Size = New System.Drawing.Size(420, 496)
        Me.textBox1.TabIndex = 1
        Me.ClientSize = New System.Drawing.Size(616, 525)
        Me.Controls.Add(Me.textBox1)
        Me.Controls.Add(Me.listBox1)
        Me.Text = "Select a SystemInformation property to get the value of"
    End Sub
        
    <STAThread()>  _
    Shared Sub Main()
        Application.Run(New SystemInfoBrowserForm())
    End Sub

End Class

Remarques

La propriété MouseWheelScrollLines indique le nombre de lignes à faire défiler, par défaut, dans un contrôle multiligne qui a une barre de défilement.The MouseWheelScrollLines property indicates how many lines to scroll, by default, in a multi-line control that has a scroll bar. Les paramètres système correspondants dans le kit de développement Platform SDK sont SPI_GETWHEELSCROLLLINES et SPI_SETWHEELSCROLLLINES.The corresponding Platform SDK system-wide parameters are SPI_GETWHEELSCROLLLINES and SPI_SETWHEELSCROLLLINES. Pour plus d’informations sur les paramètres à l’ensemble du système, consultez SystemParametersInfo.For more information about system-wide parameters, see SystemParametersInfo.

Notes

Veillez à gérer le cas spécial qui se produit si l’option de souris « un écran à la fois » est sélectionnée.Be sure to handle the special case that occurs if the "One screen at a time" mouse option is selected. Dans ce cas, la propriété MouseWheelScrollLines a la valeur-1.In this case, the MouseWheelScrollLines property has a value of -1.

S’applique à

Voir aussi