SystemInformation.DragSize Vlastnost
Definice
Důležité
Některé informace platí pro předběžně vydaný produkt, který se může zásadně změnit, než ho výrobce nebo autor vydá. Microsoft neposkytuje žádné záruky, výslovné ani předpokládané, týkající se zde uváděných informací.
Získá šířku a výšku obdélníku uprostřed v místě, kde bylo tlačítko myši stisknuto, ve kterém operace přetažení nezačne.
public:
static property System::Drawing::Size DragSize { System::Drawing::Size get(); };public static System.Drawing.Size DragSize { get; }static member DragSize : System.Drawing.SizePublic Shared ReadOnly Property DragSize As SizeHodnota vlastnosti
Určuje Size oblast obdélníku v pixelech uprostřed místa, ve kterém bylo tlačítko myši stisknuto, ve kterém operace přetažení nezačne.
Příklady
Následující příklad kódu vypíše všechny vlastnosti SystemInformation třídy a ListBox zobrazí aktuální hodnotu vlastnosti v objektu TextBox při výběru položky seznamu.
#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
Poznámky
Vlastnost DragSize označuje velikost obdélníku v pixelech uprostřed kolem bodu, ve kterém bylo tlačítko myši stisknuto. Systém Windows používá obdélník jako hranici, ve které nespustí operaci přetažení.
Uživatel může podržet tlačítko myši dolů a pohybovat myší v této oblasti před zahájením operace přetažení, což uživateli umožňuje snadno kliknout a uvolnit tlačítko myši, aniž by neúmyslně zahájil operaci přetažení.
Platí pro
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