VisualStyleElement Classe
Definizione
Importante
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Identifica un controllo o un elemento di interfaccia utente disegnato con stili di visualizzazione.
public ref class VisualStyleElementpublic class VisualStyleElementtype VisualStyleElement = classPublic Class VisualStyleElement- Ereditarietà
-
VisualStyleElement
Esempio
L'esempio di codice seguente è un'applicazione completa che fornisce un'interfaccia utente per esplorare e disegnare tutti gli VisualStyleElement oggetti esposti dallo System.Windows.Forms.VisualStyles spazio dei nomi . Per visualizzare un elemento, usare il ListView controllo sul lato sinistro della finestra per passare al nodo che rappresenta lo stato dell'elemento da disegnare e quindi fare clic sul nodo. In questo esempio verrà disegnato l'elemento selezionato solo se l'elemento è definito dallo stile di visualizzazione corrente.
#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>
#using <System.dll>
using namespace System;
using namespace System::Text;
using namespace System::Drawing;
using namespace System::Collections::Generic;
using namespace System::Reflection;
using namespace System::Windows::Forms;
using namespace System::Windows::Forms::VisualStyles;
namespace VisualStyleElementViewer
{
public ref class ElementViewer : public UserControl
{
private:
VisualStyleElement^ element;
VisualStyleRenderer^ renderer;
Dictionary<String^, VisualStyleElement^>^ elementDictionary;
Rectangle descriptionRect;
Rectangle displayRect;
Rectangle displayRectFull;
System::Drawing::Size currentTrueSize;
StringBuilder^ elementDescription;
Label^ infoLabel;
TreeView^ treeView;
DomainUpDown^ domainUpDown;
bool drawElement;
public:
ElementViewer():UserControl()
{
elementDictionary =
gcnew Dictionary<String^, VisualStyleElement^>();
currentTrueSize = System::Drawing::Size();
elementDescription = gcnew StringBuilder();
infoLabel = gcnew Label();
treeView = gcnew TreeView();
domainUpDown = gcnew DomainUpDown();
this->Location = Point(10, 10);
this->Size = System::Drawing::Size(650, 500);
this->Text = "VisualStyleElement Viewer";
this->Font = SystemFonts::IconTitleFont;
this->BackColor = Color::White;
this->BorderStyle = System::Windows::Forms::BorderStyle::Fixed3D;
this->AutoSize = true;
this->Load += gcnew EventHandler(this,
&ElementViewer::ElementViewer_Load);
}
private:
void ElementViewer_Load(Object^ sender, EventArgs^ e)
{
// Make sure the visual styles are enabled before
// going any further.
if (!Application::RenderWithVisualStyles)
{
return;
}
infoLabel->Location = Point(320, 10);
infoLabel->Size = System::Drawing::Size(300, 60);
infoLabel->Text = "Expand the element class nodes " +
"in the tree view to access visual style elements. " +
"Click an element name to draw the element below. To " +
"change the size of a resizable element, use the " +
"spin control.";
domainUpDown->Location = Point(320, 80);
domainUpDown->Size = System::Drawing::Size(70, 30);
domainUpDown->ReadOnly = true;
domainUpDown->Items->Add(elementSizes::Large);
domainUpDown->Items->Add(elementSizes::Medium);
domainUpDown->Items->Add(elementSizes::TrueSize);
domainUpDown->SelectedIndex = 2;
domainUpDown->SelectedItemChanged +=
gcnew EventHandler(this,
&ElementViewer::DomainUpDown_SelectedItemChanged);
domainUpDown->DownButton();
descriptionRect = Rectangle(320, 120, 250, 50);
displayRect = Rectangle(320, 160, 0, 0);
displayRectFull = Rectangle(320, 160, 300, 200);
// Initialize the element and renderer to known good values.
element = VisualStyleElement::Button::PushButton::Normal;
renderer = gcnew VisualStyleRenderer(element);
SetupElementCollection();
SetupTreeView();
this->Controls->AddRange(gcnew array<Control^>{treeView,
domainUpDown, infoLabel });
}
// Use reflection to build a Dictionary of all
// VisualStyleElement objects exposed in the
// System.Windows.Forms.VisualStyles namespace.
private:
void SetupElementCollection()
{
StringBuilder^ elementName = gcnew StringBuilder();
VisualStyleElement^ currentElement;
int plusSignIndex = 0;
// Get array of first-level nested types within
// VisualStyleElement; these are the element classes.
array<Type^>^ elementClasses =
VisualStyleElement::typeid->GetNestedTypes();
for each (Type^ elementClass in elementClasses)
{
// Get an array of second-level nested types within
// VisualStyleElement; these are the element parts.
array<Type^>^ elementParts = elementClass->GetNestedTypes();
// Get the index of the first '+' character in
// the full element class name.
plusSignIndex = elementClass->FullName->IndexOf('+');
for each (Type^ elementPart in elementParts)
{
// Get an array of static property details
// for the current type. Each of these types have
// properties that return VisualStyleElement objects.
array<PropertyInfo^>^ elementProperties =
elementPart->GetProperties(BindingFlags::Static |
BindingFlags::Public);
// For each property, insert the unique full element
// name and the element into the collection.
for each(PropertyInfo^ elementProperty in
elementProperties)
{
// Get the element.
currentElement =
(VisualStyleElement^)elementProperty->
GetValue(nullptr, BindingFlags::Static, nullptr,
nullptr, nullptr);
// Append the full element name.
elementName->Append(elementClass->FullName,
plusSignIndex + 1,
elementClass->FullName->Length -
plusSignIndex - 1);
elementName->Append("." +
elementPart->Name + "." +
elementProperty->Name);
// Add the element and element name to
// the Dictionary.
elementDictionary->Add(elementName->ToString(),
currentElement);
// Clear the element name for the
// next iteration.
elementName->Remove(0, elementName->Length);
}
}
}
}
// Initialize the tree view with the element names.
private:
void SetupTreeView()
{
treeView->Location = Point(10, 10);
treeView->Size = System::Drawing::Size(300, 450);
// treeView->BorderStyle = BorderStyle.FixedSingle;
treeView->BackColor = Color::WhiteSmoke;
treeView->SelectedNode = nullptr;
treeView->AfterSelect +=
gcnew TreeViewEventHandler(this,
&ElementViewer::TreeView_AfterSelect);
treeView->BeginUpdate();
// An index into the top-level tree nodes.
int nodeIndex = 0;
// An index into the first '.' character in an element name.
int firstDotIndex = 0;
// Initialize the element class name to compare
// with the class name of the first element
// in the Dictionary, and set this name to the first
// top-level node.
StringBuilder^ compareClassName =
gcnew StringBuilder("Button");
treeView->Nodes->Add(
gcnew TreeNode(compareClassName->ToString()));
// The current element class name.
StringBuilder^ currentClassName = gcnew StringBuilder();
// The text for each second-level node.
StringBuilder^ nodeText = gcnew StringBuilder();
for each(KeyValuePair<String^, VisualStyleElement^>^ entry
in elementDictionary)
{
// Isolate the class name of the current element.
firstDotIndex = entry->Key->IndexOf('.');
currentClassName->Append(entry->Key, 0, firstDotIndex);
// Determine whether we need to increment to the next
// element class.
if (currentClassName->ToString() !=
compareClassName->ToString())
{
// Increment the index to the next top-level node
// in the tree view.
nodeIndex++;
// Get the new class name to compare with.
compareClassName->Remove(0, compareClassName->Length);
compareClassName->Append(entry->Key);
compareClassName->Remove(firstDotIndex,
compareClassName->Length - firstDotIndex);
// Add a new top-level node to the tree view.
treeView->Nodes->Add(
gcnew TreeNode(compareClassName->ToString()));
}
// Get the text for the new second-level node.
nodeText->Append(entry->Key, firstDotIndex + 1,
entry->Key->Length - firstDotIndex - 1);
// Create and insert the new second-level node.
TreeNode^ newNode = gcnew TreeNode(nodeText->ToString());
newNode->Name = entry->Key;
treeView->Nodes[nodeIndex]->Nodes->Add(newNode);
currentClassName->Remove(0, currentClassName->Length);
nodeText->Remove(0, nodeText->Length);
}
treeView->EndUpdate();
}
protected:
virtual void OnPaint(PaintEventArgs^ e) override
{
__super::OnPaint(e);
// Do nothing further if visual styles are disabled.
if (!Application::RenderWithVisualStyles)
{
this->Text = "Visual styles are disabled.";
TextRenderer::DrawText(e->Graphics, this->Text, this->Font,
this->Location, this->ForeColor);
return;
}
// Draw the element description.
TextRenderer::DrawText(e->Graphics, elementDescription->ToString(),
this->Font, descriptionRect, this->ForeColor,
TextFormatFlags::WordBreak);
// Draw the element, if an element is selected.
if (drawElement)
{
renderer->DrawBackground(e->Graphics, this->displayRect);
}
}
// Set the element to draw.
private:
void TreeView_AfterSelect(Object^ sender, TreeViewEventArgs^ e)
{
// Clear the element description.
elementDescription->Remove(0, elementDescription->Length);
// If the user clicked a first-level node, disable drawing.
if (e->Node->Nodes->Count > 0)
{
drawElement = false;
elementDescription->Append("No element is selected");
domainUpDown->Enabled = false;
}
// The user clicked an element node.
else
{
// Add the element name to the description.
elementDescription->Append(e->Node->Text);
// Get the element that corresponds to the selected
// node's name.
String^ key = e->Node->Name;
element = elementDictionary[key];
// Disable resizing if the element is not defined.
if (!VisualStyleRenderer::IsElementDefined(element))
{
drawElement = false;
elementDescription->Append(" is not defined.");
domainUpDown->Enabled = false;
}
else
{
// Set the element to the renderer.
drawElement = true;
renderer->SetParameters(element);
elementDescription->Append(" is defined.");
// Get the system-defined size of the element.
Graphics^ g = this->CreateGraphics();
currentTrueSize = renderer->GetPartSize(g,
ThemeSizeType::True);
delete g;
displayRect.Size = currentTrueSize;
domainUpDown->Enabled = true;
domainUpDown->SelectedIndex = 2;
}
}
Invalidate();
}
// Resize the element display area.
private:
void DomainUpDown_SelectedItemChanged(Object^ sender,
EventArgs^ e)
{
switch ((int)domainUpDown->SelectedItem)
{
case this->elementSizes::TrueSize:
displayRect.Size = currentTrueSize;
break;
case this->elementSizes::Medium:
displayRect.Size =
System::Drawing::Size(displayRectFull.Width / 2,
displayRectFull.Height / 2);
break;
case this->elementSizes::Large:
displayRect.Size = displayRectFull.Size;
break;
}
Invalidate();
}
// These values represent the options in the UpDown control.
private:
enum class elementSizes
{
TrueSize,
Medium,
Large
};
};
public ref class ElementViewerForm : public Form
{
public:
ElementViewerForm()
{
ElementViewer^ elementViewer = gcnew ElementViewer();
this->Controls->Add(elementViewer);
this->Text = elementViewer->Text;
this->Size = System::Drawing::Size(700, 550);
}
};
}
using namespace VisualStyleElementViewer;
[STAThread]
int main()
{
Application::EnableVisualStyles();
Application::Run(gcnew ElementViewerForm());
}
using System;
using System.Text;
using System.Drawing;
using System.Collections.Generic;
using System.Reflection;
using System.Windows.Forms;
using System.Windows.Forms.VisualStyles;
namespace VisualStyleElementViewer
{
class Form1 : Form
{
public Form1()
{
ElementViewer ElementViewer1 = new ElementViewer();
this.Controls.Add(ElementViewer1);
this.Text = ElementViewer1.Text;
this.Size = new Size(700, 550);
}
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.Run(new Form1());
}
}
public class ElementViewer : UserControl
{
private VisualStyleElement element;
private VisualStyleRenderer renderer;
private Dictionary<string, VisualStyleElement> elementDictionary =
new Dictionary<string, VisualStyleElement>();
private Rectangle descriptionRect;
private Rectangle displayRect;
private Rectangle displayRectFull;
private Size currentTrueSize = new Size();
private StringBuilder elementDescription = new StringBuilder();
private Label label1 = new Label();
private TreeView treeView1 = new TreeView();
private DomainUpDown domainUpDown1 = new DomainUpDown();
private bool drawElement = false;
public ElementViewer()
: base()
{
this.Location = new Point(10, 10);
this.Size = new Size(650, 500);
this.Text = "VisualStyleElement Viewer";
this.Font = SystemFonts.IconTitleFont;
this.BackColor = Color.White;
this.BorderStyle = BorderStyle.Fixed3D;
this.AutoSize = true;
this.Load += new EventHandler(ElementViewer_Load);
}
void ElementViewer_Load(object sender, EventArgs e)
{
// Make sure the visual styles are enabled before
// going any further.
if (!Application.RenderWithVisualStyles)
{
return;
}
label1.Location = new Point(320, 10);
label1.Size = new Size(300, 60);
label1.Text = "Expand the element class nodes " +
"in the tree view to access visual style elements. " +
"Click an element name to draw the element below. To " +
"change the size of a resizable element, use the " +
"spin control.";
domainUpDown1.Location = new Point(320, 80);
domainUpDown1.Size = new Size(70, 30);
domainUpDown1.ReadOnly = true;
domainUpDown1.Items.Add(elementSizes.Large);
domainUpDown1.Items.Add(elementSizes.Medium);
domainUpDown1.Items.Add(elementSizes.TrueSize);
domainUpDown1.SelectedIndex = 2;
domainUpDown1.SelectedItemChanged +=
new EventHandler(domainUpDown1_SelectedItemChanged);
domainUpDown1.DownButton();
descriptionRect = new Rectangle(320, 120, 250, 50);
displayRect = new Rectangle(320, 160, 0, 0);
displayRectFull = new Rectangle(320, 160, 300, 200);
// Initialize the element and renderer to known good values.
element = VisualStyleElement.Button.PushButton.Normal;
renderer = new VisualStyleRenderer(element);
SetupElementCollection();
SetupTreeView();
this.Controls.AddRange(new Control[] { treeView1,
domainUpDown1, label1 });
}
// Use reflection to build a Dictionary of all
// VisualStyleElement objects exposed in the
// System.Windows.Forms.VisualStyles namespace.
private void SetupElementCollection()
{
StringBuilder elementName = new StringBuilder();
VisualStyleElement currentElement;
int plusSignIndex = 0;
// Get array of first-level nested types within
// VisualStyleElement; these are the element classes.
Type[] elementClasses =
typeof(VisualStyleElement).GetNestedTypes();
foreach (Type elementClass in elementClasses)
{
// Get an array of second-level nested types within
// VisualStyleElement; these are the element parts.
Type[] elementParts = elementClass.GetNestedTypes();
// Get the index of the first '+' character in
// the full element class name.
plusSignIndex = elementClass.FullName.IndexOf('+');
foreach (Type elementPart in elementParts)
{
// Get an array of static property details
// for the current type. Each of these types have
// properties that return VisualStyleElement objects.
PropertyInfo[] elementProperties =
elementPart.GetProperties(BindingFlags.Static |
BindingFlags.Public);
// For each property, insert the unique full element
// name and the element into the collection.
foreach (PropertyInfo elementProperty in
elementProperties)
{
// Get the element.
currentElement =
(VisualStyleElement)elementProperty.
GetValue(null, BindingFlags.Static, null,
null, null);
// Append the full element name.
elementName.Append(elementClass.FullName,
plusSignIndex + 1,
elementClass.FullName.Length -
plusSignIndex - 1);
elementName.Append("." +
elementPart.Name.ToString() + "." +
elementProperty.Name);
// Add the element and element name to
// the Dictionary.
elementDictionary.Add(elementName.ToString(),
currentElement);
// Clear the element name for the
// next iteration.
elementName.Remove(0, elementName.Length);
}
}
}
}
// Initialize the tree view with the element names.
private void SetupTreeView()
{
treeView1.Location = new Point(10, 10);
treeView1.Size = new Size(300, 450);
treeView1.BorderStyle = BorderStyle.FixedSingle;
treeView1.BackColor = Color.WhiteSmoke;
treeView1.SelectedNode = null;
treeView1.AfterSelect +=
new TreeViewEventHandler(treeView1_AfterSelect);
treeView1.BeginUpdate();
// An index into the top-level tree nodes.
int nodeIndex = 0;
// An index into the first '.' character in an element name.
int firstDotIndex = 0;
// Initialize the element class name to compare
// with the class name of the first element
// in the Dictionary, and set this name to the first
// top-level node.
StringBuilder compareClassName =
new StringBuilder("Button");
treeView1.Nodes.Add(
new TreeNode(compareClassName.ToString()));
// The current element class name.
StringBuilder currentClassName = new StringBuilder();
// The text for each second-level node.
StringBuilder nodeText = new StringBuilder();
foreach (KeyValuePair<string, VisualStyleElement> entry
in elementDictionary)
{
// Isolate the class name of the current element.
firstDotIndex = entry.Key.IndexOf('.');
currentClassName.Append(entry.Key, 0, firstDotIndex);
// Determine whether we need to increment to the next
// element class.
if (currentClassName.ToString() !=
compareClassName.ToString())
{
// Increment the index to the next top-level node
// in the tree view.
nodeIndex++;
// Get the new class name to compare with.
compareClassName.Remove(0, compareClassName.Length);
compareClassName.Append(entry.Key);
compareClassName.Remove(firstDotIndex,
compareClassName.Length - firstDotIndex);
// Add a new top-level node to the tree view.
treeView1.Nodes.Add(
new TreeNode(compareClassName.ToString()));
}
// Get the text for the new second-level node.
nodeText.Append(entry.Key, firstDotIndex + 1,
entry.Key.Length - firstDotIndex - 1);
// Create and insert the new second-level node.
TreeNode newNode = new TreeNode(nodeText.ToString());
newNode.Name = entry.Key;
treeView1.Nodes[nodeIndex].Nodes.Add(newNode);
currentClassName.Remove(0, currentClassName.Length);
nodeText.Remove(0, nodeText.Length);
}
treeView1.EndUpdate();
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
// Do nothing further if visual styles are disabled.
if (!Application.RenderWithVisualStyles)
{
this.Text = "Visual styles are disabled.";
TextRenderer.DrawText(e.Graphics, this.Text, this.Font,
this.Location, this.ForeColor);
return;
}
// Draw the element description.
TextRenderer.DrawText(e.Graphics, elementDescription.ToString(),
this.Font, descriptionRect, this.ForeColor,
TextFormatFlags.WordBreak);
// Draw the element, if an element is selected.
if (drawElement)
{
renderer.DrawBackground(e.Graphics, this.displayRect);
}
}
// Set the element to draw.
void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
{
// Clear the element description.
elementDescription.Remove(0, elementDescription.Length);
// If the user clicked a first-level node, disable drawing.
if (e.Node.Nodes.Count > 0)
{
drawElement = false;
elementDescription.Append("No element is selected");
domainUpDown1.Enabled = false;
}
// The user clicked an element node.
else
{
// Add the element name to the description.
elementDescription.Append(e.Node.Text);
// Get the element that corresponds to the selected
// node's name.
String key = e.Node.Name;
element = elementDictionary[key];
// Disable resizing if the element is not defined.
if (!VisualStyleRenderer.IsElementDefined(element))
{
drawElement = false;
elementDescription.Append(" is not defined.");
domainUpDown1.Enabled = false;
}
else
{
// Set the element to the renderer.
drawElement = true;
renderer.SetParameters(element);
elementDescription.Append(" is defined.");
// Get the system-defined size of the element.
Graphics g = this.CreateGraphics();
currentTrueSize = renderer.GetPartSize(g,
ThemeSizeType.True);
g.Dispose();
displayRect.Size = currentTrueSize;
domainUpDown1.Enabled = true;
domainUpDown1.SelectedIndex = 2;
}
}
Invalidate();
}
// Resize the element display area.
void domainUpDown1_SelectedItemChanged(object sender,
EventArgs e)
{
switch ((int)domainUpDown1.SelectedItem)
{
case (int)elementSizes.TrueSize:
displayRect.Size = currentTrueSize;
break;
case (int)elementSizes.Medium:
displayRect.Size =
new Size(displayRectFull.Width / 2,
displayRectFull.Height / 2);
break;
case (int)elementSizes.Large:
displayRect.Size = displayRectFull.Size;
break;
}
Invalidate();
}
// These values represent the options in the UpDown control.
private enum elementSizes
{
TrueSize,
Medium,
Large
};
}
}
Imports System.Text
Imports System.Drawing
Imports System.Collections.Generic
Imports System.Reflection
Imports System.Windows.Forms
Imports System.Windows.Forms.VisualStyles
Namespace VisualStyleElementViewer
Class Form1
Inherits Form
Public Sub New()
Dim ElementViewer1 As New ElementViewer()
With Me
.Controls.Add(ElementViewer1)
.Text = ElementViewer1.Text
.Size = New Size(700, 550)
End With
End Sub
<STAThread()> Shared Sub Main()
Application.EnableVisualStyles()
Application.Run(New Form1())
End Sub
End Class
Public Class ElementViewer
Inherits UserControl
Private element As VisualStyleElement
Private renderer As VisualStyleRenderer
Private elementDictionary As New Dictionary(Of String, _
VisualStyleElement)
Private descriptionRect As Rectangle
Private displayRect As Rectangle
Private displayRectFull As Rectangle
Private currentTrueSize As New Size()
Private elementDescription As New StringBuilder()
Private label1 As New Label()
Private WithEvents treeView1 As New TreeView()
Private WithEvents domainUpDown1 As New DomainUpDown()
Private drawElement As Boolean = False
Public Sub New()
With Me
.Location = New Point(10, 10)
.Size = New Size(650, 500)
.Text = "VisualStyleElement Viewer"
.Font = SystemFonts.IconTitleFont
.BackColor = Color.White
.BorderStyle = BorderStyle.Fixed3D
.AutoSize = True
End With
End Sub
Private Sub ElementViewer_Load(ByVal sender As Object, _
ByVal e As EventArgs) Handles Me.Load
' Make sure the visual styles are enabled before
' going any further.
If Not Application.RenderWithVisualStyles Then
Return
End If
With label1
.Location = New Point(320, 10)
.Size = New Size(300, 60)
.Text = "Expand the element class nodes in the " + _
"tree view to access visual style elements. " + _
"Click an element name to draw the element " + _
"below. To change the size of a resizable " + _
"element, use the spin control."
End With
With domainUpDown1
.Location = New Point(320, 80)
.Size = New Size(70, 30)
.ReadOnly = True
.Items.Add(elementSizes.Large)
.Items.Add(elementSizes.Medium)
.Items.Add(elementSizes.TrueSize)
.SelectedIndex = 2
.DownButton()
End With
descriptionRect = New Rectangle(320, 120, 250, 50)
displayRect = New Rectangle(320, 160, 0, 0)
displayRectFull = New Rectangle(320, 160, 300, 200)
' Initialize the element and renderer to known good values.
element = VisualStyleElement.Button.PushButton.Normal
renderer = New VisualStyleRenderer(element)
SetupElementCollection()
SetupTreeView()
Me.Controls.AddRange(New Control() {treeView1, _
domainUpDown1, label1})
End Sub
' Use reflection to build a Dictionary of all
' VisualStyleElement objects exposed in the
' System.Windows.Forms.VisualStyles namespace.
Private Sub SetupElementCollection()
Dim elementName As New StringBuilder()
Dim currentElement As VisualStyleElement
Dim tempObject As Object
Dim plusSignIndex As Integer = 0
' Get array of first-level nested types within
' VisualStyleElement; these are the element classes.
Dim elementClasses As Type() = _
GetType(VisualStyleElement).GetNestedTypes()
Dim elementClass As Type
For Each elementClass In elementClasses
' Get an array of second-level nested types within
' VisualStyleElement; these are the element parts.
Dim elementParts As Type() = _
elementClass.GetNestedTypes()
' Get the index of the first '+' character in
' the full element class name.
plusSignIndex = elementClass.FullName.IndexOf("+")
Dim elementPart As Type
For Each elementPart In elementParts
' Get an array of Shared property details
' for the current type. Each of these types have
' properties that return VisualStyleElement objects.
Dim elementProperties As PropertyInfo() = _
elementPart.GetProperties( _
(BindingFlags.Static Or BindingFlags.Public))
' For each property, insert the unique full element
' name and the element into the collection.
Dim elementProperty As PropertyInfo
For Each elementProperty In elementProperties
' Get the element.
tempObject = elementProperty.GetValue( _
Nothing, BindingFlags.Static, Nothing, _
Nothing, Nothing)
currentElement = CType(tempObject, _
VisualStyleElement)
' Append the full element name.
elementName.Append(elementClass.FullName, _
plusSignIndex + 1, _
elementClass.FullName.Length - _
plusSignIndex - 1)
elementName.Append(("." + _
elementPart.Name.ToString() + _
"." + elementProperty.Name))
' Add the element and element name to
' the Dictionary.
elementDictionary.Add(elementName.ToString(), _
currentElement)
' Clear the element name for the next iteration.
elementName.Remove(0, elementName.Length)
Next elementProperty
Next elementPart
Next elementClass
End Sub
' Initialize the tree view with the element names.
Private Sub SetupTreeView()
With treeView1
.Location = New Point(10, 10)
.Size = New Size(300, 450)
.BorderStyle = BorderStyle.FixedSingle
.BackColor = Color.WhiteSmoke
.SelectedNode = Nothing
.BeginUpdate()
End With
' An index into the top-level tree nodes.
Dim nodeIndex As Integer = 0
' An index into the first '.' character in an element name.
Dim firstDotIndex As Integer = 0
' Initialize the element class name to compare
' with the class name of the first element
' in the Dictionary, and set this name to the first
' top-level node.
Dim compareClassName As New StringBuilder("Button")
treeView1.Nodes.Add( _
New TreeNode(compareClassName.ToString()))
' The current element class name.
Dim currentClassName As New StringBuilder()
' The text for each second-level node.
Dim nodeText As New StringBuilder()
Dim entry As KeyValuePair(Of String, VisualStyleElement)
For Each entry In elementDictionary
' Isolate the class name of the current element.
firstDotIndex = entry.Key.IndexOf(".")
currentClassName.Append(entry.Key, 0, firstDotIndex)
' Determine whether we need to increment to the next
' element class.
If currentClassName.ToString() <> _
compareClassName.ToString() Then
' Increment the index to the next top-level node
' in the tree view.
nodeIndex += 1
' Update the class name to compare with.
compareClassName.Remove(0, compareClassName.Length)
compareClassName.Append(entry.Key)
compareClassName.Remove(firstDotIndex, _
compareClassName.Length - firstDotIndex)
' Add a new top-level node to the tree view.
Dim node As New TreeNode(compareClassName.ToString())
treeView1.Nodes.Add(node)
End If
' Get the text for the new second-level node.
nodeText.Append(entry.Key, firstDotIndex + 1, _
entry.Key.Length - firstDotIndex - 1)
' Create and insert the new second-level node.
Dim newNode As New TreeNode(nodeText.ToString())
newNode.Name = entry.Key
treeView1.Nodes(nodeIndex).Nodes.Add(newNode)
currentClassName.Remove(0, currentClassName.Length)
nodeText.Remove(0, nodeText.Length)
Next entry
treeView1.EndUpdate()
End Sub
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
MyBase.OnPaint(e)
' Do nothing further if visual styles are disabled.
If Not Application.RenderWithVisualStyles Then
Me.Text = "Visual styles are disabled."
TextRenderer.DrawText(e.Graphics, Me.Text, Me.Font, _
Me.Location, Me.ForeColor)
Return
End If
' Draw the element description.
TextRenderer.DrawText(e.Graphics, _
elementDescription.ToString(), Me.Font, _
descriptionRect, Me.ForeColor, _
TextFormatFlags.WordBreak)
' Draw the element, if an element is selected.
If drawElement Then
renderer.DrawBackground(e.Graphics, Me.displayRect)
End If
End Sub
' Set the element to draw.
Private Sub treeView1_AfterSelect(ByVal sender As Object, _
ByVal e As TreeViewEventArgs) Handles treeView1.AfterSelect
' Clear the element description.
elementDescription.Remove(0, elementDescription.Length)
' If the user clicked a first-level node, disable drawing.
If e.Node.Nodes.Count > 0 Then
drawElement = False
elementDescription.Append("No element is selected")
domainUpDown1.Enabled = False
' The user clicked an element node.
Else
' Add the element name to the description.
elementDescription.Append(e.Node.Text)
' Get the element that corresponds to the selected
' node's name.
Dim key As String = e.Node.Name
element = elementDictionary(key)
' Disable resizing if the element is not defined.
If Not VisualStyleRenderer.IsElementDefined(element) Then
drawElement = False
elementDescription.Append(" is not defined.")
domainUpDown1.Enabled = False
Else
' Set the element to the renderer.
drawElement = True
renderer.SetParameters(element)
elementDescription.Append(" is defined.")
' Get the system-defined size of the element.
Dim g As Graphics = Me.CreateGraphics()
currentTrueSize = renderer.GetPartSize(g, _
ThemeSizeType.True)
g.Dispose()
displayRect.Size = currentTrueSize
domainUpDown1.Enabled = True
domainUpDown1.SelectedIndex = 2
End If
End If
Invalidate()
End Sub
' Resize the element display area.
Private Sub domainUpDown1_SelectedItemChanged(ByVal sender As Object, _
ByVal e As EventArgs) _
Handles domainUpDown1.SelectedItemChanged
Select Case CInt(domainUpDown1.SelectedItem)
Case CInt(elementSizes.TrueSize)
displayRect.Size = currentTrueSize
Case CInt(elementSizes.Medium)
displayRect.Size = _
New Size(displayRectFull.Width / 2, _
displayRectFull.Height / 2)
Case CInt(elementSizes.Large)
displayRect.Size = displayRectFull.Size
End Select
Invalidate()
End Sub
' These values represent the options in the UpDown control.
Private Enum elementSizes
TrueSize
Medium
Large
End Enum
End Class
End Namespace
Commenti
La VisualStyleElement classe identifica un controllo Windows o un elemento dell'interfaccia utente definito dallo stile di visualizzazione corrente del sistema operativo. Un elemento dello stile di visualizzazione viene definito in termini di classe, parte e stato:
La classe identifica un gruppo di elementi dello stile di visualizzazione correlati che vengono in genere disegnati insieme. La classe viene specificata dalla ClassName proprietà .
La parte definisce un membro discreto di una classe. La parte viene specificata dalla Part proprietà .
Lo stato descrive lo stato di visualizzazione corrente dell'elemento definito dalla classe e dalla parte. Lo stato viene specificato dalla State proprietà .
Lo System.Windows.Forms.VisualStyles spazio dei nomi espone centinaia di VisualStyleElement oggetti che rappresentano i controlli e gli elementi dell'interfaccia utente che possono essere definiti da uno stile di visualizzazione. Questi oggetti vengono esposti come static proprietà di classi annidate di VisualStyleElement. Per ogni proprietà, il nome completo della classe proprietaria rappresenta la classe e la parte dell'elemento disegnato e il nome della proprietà rappresenta lo stato dell'elemento. Ad esempio, la VisualStyleElement.Button.PushButton.Pressed proprietà restituisce un VisualStyleElement oggetto che può essere utilizzato per disegnare un pulsante nello stato premuto con stili di visualizzazione. Il Pressed nome della proprietà corrisponde allo stato , PushButton corrisponde alla parte e Button identifica la classe dell'elemento dello stile di visualizzazione.
Per disegnare un elemento dello stile di visualizzazione, creare un VisualStyleRendereroggetto , impostarlo sull'elemento VisualStyleElement da disegnare e quindi chiamare il DrawBackground metodo . Per determinare se lo stile di visualizzazione corrente fornisce una definizione per un particolare elemento, chiamare il IsElementDefined metodo con l'elemento come argomento.
VisualStyleElement ed VisualStyleRenderer eseguire il wrapping della funzionalità dell'API degli stili di visualizzazione dalla parte shell di Windows di Windows Platform SDK. Per altre informazioni sugli stili di visualizzazione, vedere Stili di visualizzazione.
Proprietà
| ClassName |
Ottiene il nome della classe dell'elemento dello stile di visualizzazione rappresentato da VisualStyleElement. |
| Part |
Ottiene il valore che indica la parte dell'elemento dello stile di visualizzazione rappresentato da VisualStyleElement. |
| State |
Ottiene un valore che indica lo stato dell'elemento dello stile di visualizzazione rappresentato da VisualStyleElement. |
Metodi
| CreateElement(String, Int32, Int32) |
Crea un nuovo elemento dello stile di visualizzazione dai valori di classe, parte e stato specificati. |
| Equals(Object) |
Determina se l'oggetto specificato è uguale all'oggetto corrente. (Ereditato da Object) |
| GetHashCode() |
Funge da funzione hash predefinita. (Ereditato da Object) |
| GetType() |
Ottiene l'oggetto Type dell'istanza corrente. (Ereditato da Object) |
| MemberwiseClone() |
Crea una copia superficiale dell'oggetto Object corrente. (Ereditato da Object) |
| ToString() |
Restituisce una stringa che rappresenta l'oggetto corrente. (Ereditato da Object) |
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