SystemInformation.MouseWheelScrollLines SystemInformation.MouseWheelScrollLines SystemInformation.MouseWheelScrollLines SystemInformation.MouseWheelScrollLines Property

定义

获取滚动鼠标轮时所滚动过的行数。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

属性值

单次鼠标轮旋转所滚动的行数,或 -1(如果选中“一次滚动一个屏幕”鼠标选项)。The number of lines to scroll on a mouse wheel rotation, or -1 if the "One screen at a time" mouse option is selected.

示例

下面的代码示例列出了SystemInformation ListBox中的类的所有属性, 并在选定列表项TextBox时显示中的属性的当前值。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 Microsoft.VisualBasic
Imports System
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

注解

MouseWheelScrollLines属性指示默认情况下在具有滚动条的多行控件中滚动的行数。The MouseWheelScrollLines property indicates how many lines to scroll, by default, in a multi-line control that has a scroll bar. 对应的 Platform SDK 系统级参数为 SPI_GETWHEELSCROLLLINES 和 SPI_SETWHEELSCROLLLINES。The corresponding Platform SDK system-wide parameters are SPI_GETWHEELSCROLLLINES and SPI_SETWHEELSCROLLLINES. 有关系统范围内参数的详细信息, 请参阅中的平台 SDK 文档http://msdn.microsoft.com中的 "SystemParametersInfo"。For more information about system-wide parameters, see "SystemParametersInfo" in the Platform SDK documentation at http://msdn.microsoft.com.

备注

如果选择了 "一次一个屏幕" 鼠标选项, 则一定要处理出现的特殊情况。Be sure to handle the special case that occurs if the "One screen at a time" mouse option is selected. 在这种情况下MouseWheelScrollLines , 属性的值为-1。In this case, the MouseWheelScrollLines property has a value of -1.

适用于

另请参阅