SystemInformation.DragSize 属性

获取以鼠标按钮的按下点为中心的矩形的宽度和高度，在该矩形内不会开始拖动操作。

**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms（在 system.windows.forms.dll 中）

语法

声明
Public Shared ReadOnly Property DragSize As Size
用法
Dim value As Size

value = SystemInformation.DragSize

public static Size DragSize { get; }

public:
static property Size DragSize {
    Size get ();
}

/** @property */
public static Size get_DragSize ()

public static function get DragSize () : Size

属性值

Size，指定以鼠标按钮的按下点为中心的矩形区域（以像素为单位），在该矩形区域内不会开始拖动操作。

备注

DragSize 属性指示以鼠标按钮按下点为中心的矩形的大小（以像素为单位）。Windows 将该矩形用作边界，在其中不会开始拖动操作。

在开始拖动操作之前，用户可以按住鼠标按钮并在此区域中移动鼠标，这样使用户可以轻松地单击和释放鼠标按钮，而不会在无意中开始拖动操作。

示例

下面的代码示例将 SystemInformation 类的所有属性列在 ListBox 中，并在选择列表项时将属性的当前值显示在 TextBox 中。

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

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());
        }
    }
}

#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 );
}

package SystemInfoBrowser;

import System.*;
import System.Collections.*;
import System.ComponentModel.*;
import System.Drawing.*;
import System.Reflection.*;
import System.Windows.Forms.*;

public class SystemInfoBrowserForm extends 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 = System.Windows.Forms.SystemInformation.class.ToType();
        PropertyInfo pi[] = t.GetProperties();
        for (int i = 0; i < pi.length; i++) {
            listBox1.get_Items().Add(pi[i].get_Name());
        }
        textBox1.set_Text("The SystemInformation class has "
            + ((Int32)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.add_SelectedIndexChanged(
            new EventHandler(listBox1_SelectedIndexChanged));
        this.ResumeLayout(false);
    } //SystemInfoBrowserForm

    private void listBox1_SelectedIndexChanged(Object sender, EventArgs e)
    {
        // Return if no list item is selected.
        if (listBox1.get_SelectedIndex() == -1) {
            return;
        }
        // Get the property name from the list item.
        String propname = listBox1.get_Text();

        if (propname.Equals("PowerStatus")) {
            // Cycle and display the values of each property of the
            // PowerStatus property.
            textBox1.set_Text(textBox1.get_Text()
                + "\r\nThe value of the PowerStatus property is:");
            Type t = System.Windows.Forms.PowerStatus.class.ToType();
            PropertyInfo pi[] = t.GetProperties();
            for (int i = 0; i < pi.length; i++) {
                Object propval = pi[i].GetValue(
                    SystemInformation.get_PowerStatus(), null);
                textBox1.set_Text(textBox1.get_Text()
                    + "\r\n    PowerStatus." + pi[i].get_Name()
                    + " is: " + propval.ToString());
            }
        }
        else {
            // Display the value of the selected property of the
            // SystemInformation type.
            Type t = System.Windows.Forms.SystemInformation.class.ToType();
            PropertyInfo pi[] = t.GetProperties();
            PropertyInfo prop = null;
            for (int i = 0; i < pi.length; i++) {
                if (pi[i].get_Name().Equals(propname)) {
                    prop = pi[i];
                    break;
                }
            }
            Object propval = prop.GetValue(null, null);
            textBox1.set_Text(textBox1.get_Text() + "\r\nThe value of the "
                + propname + " property is: " + propval.ToString());
        }
    } //listBox1_SelectedIndexChanged

    private void InitForm()
    {
        // Initialize the form settings
        this.listBox1 = new System.Windows.Forms.ListBox();
        this.textBox1 = new System.Windows.Forms.TextBox();
        this.listBox1.set_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.set_Location(new System.Drawing.Point(8, 16));
        this.listBox1.set_Size(new System.Drawing.Size(172, 496));
        this.listBox1.set_TabIndex(0);
        this.textBox1.set_Anchor((System.Windows.Forms.AnchorStyles)
            (System.Windows.Forms.AnchorStyles.Top
            | System.Windows.Forms.AnchorStyles.Bottom
            | System.Windows.Forms.AnchorStyles.Right));
        this.textBox1.set_Location(new System.Drawing.Point(188, 16));
        this.textBox1.set_Multiline(true);
        this.textBox1.set_ScrollBars(System.Windows.Forms.ScrollBars.Vertical);
        this.textBox1.set_Size(new System.Drawing.Size(420, 496));
        this.textBox1.set_TabIndex(1);
        this.set_ClientSize(new System.Drawing.Size(616, 525));
        this.get_Controls().Add(this.textBox1);
        this.get_Controls().Add(this.listBox1);
        this.set_Text("Select a SystemInformation property to get the value of");
    } //InitForm

    /** @attribute STAThread()
     */
    public static void main(String[] args)
    {
        Application.Run(new SystemInfoBrowserForm());
    } //main
} //SystemInfoBrowserForm

平台

Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

请参见

参考

SystemInformation 类
SystemInformation 成员
System.Windows.Forms 命名空间
Size