VisualStyleElement Třída
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.
Identifikuje prvek ovládacího prvku nebo uživatelského rozhraní (UI), který je nakreslen vizuálními styly.
public ref class VisualStyleElementpublic class VisualStyleElementtype VisualStyleElement = classPublic Class VisualStyleElement- Dědičnost
-
VisualStyleElement
Příklady
Následující příklad kódu je kompletní aplikace, která poskytuje uživatelské rozhraní pro procházení a kreslení všech VisualStyleElement objektů vystavených oborem System.Windows.Forms.VisualStyles názvů. Chcete-li zobrazit prvek, přejděte pomocí ListView ovládacího prvku na levé straně okna na uzel, který představuje stav prvku, který chcete nakreslit, a klikněte na uzel. Tato ukázka nakreslí vybraný prvek pouze v případě, že je prvek definován aktuálním stylem vizuálu.
#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
Poznámky
Třída VisualStyleElement identifikuje prvek ovládacího prvku windows nebo uživatelského rozhraní (UI), který je definován aktuálním vizuálním stylem operačního systému. Prvek vizuálního stylu je definován z hlediska třídy, části a stavu:
Třída identifikuje skupinu souvisejících prvků vizuálního stylu, které jsou obvykle nakresleny dohromady. Třída je určena ClassName vlastností .
Část definuje diskrétní člen třídy. Část je určena Part vlastností .
Stav popisuje aktuální stav vizuálu elementu definovaného třídou a částí. Stav určuje State vlastnost .
Obor System.Windows.Forms.VisualStyles názvů zveřejňuje stovky VisualStyleElement objektů, které představují ovládací prvky a prvky uživatelského rozhraní, které mohou být definovány vizuálním stylem. Tyto objekty jsou vystaveny jako static vlastnosti vnořených tříd třídy .VisualStyleElement Pro každou vlastnost kvalifikovaný název vlastnící třídy představuje třídu a část nakresleného prvku a název vlastnosti představuje stav prvku. Například vlastnost vrátí VisualStyleElement objekt , VisualStyleElement.Button.PushButton.Pressed který lze použít k vykreslení tlačítka ve stisknutém stavu s vizuálními styly. Název Pressed vlastnosti odpovídá stavu, PushButton odpovídá části a Button identifikuje třídu elementu vizuálního stylu.
Pokud chcete nakreslit prvek vizuálního stylu, vytvořte VisualStyleRendererobjekt , nastavte ho na VisualStyleElement hodnotu, kterou chcete nakreslit, a pak zavolejte metodu DrawBackground . Chcete-li zjistit, zda aktuální vizuální styl poskytuje definici pro určitý prvek, zavolejte metodu IsElementDefined s elementem jako argumentem .
VisualStyleElement a VisualStyleRenderer zabalit funkce rozhraní API vizuálních stylů z prostředí systému Windows v sadě Windows Platform SDK. Další informace o vizuálních stylech najdete v tématu Vizuální styly.
Vlastnosti
| ClassName |
Získá název třídy elementu vizuálního stylu, který představuje VisualStyleElement . |
| Part |
Získá hodnotu označující část vizuální styl prvek, který představuje VisualStyleElement . |
| State |
Získá hodnotu označující stav elementu vizuálního stylu, který představuje VisualStyleElement . |
Metody
| CreateElement(String, Int32, Int32) |
Vytvoří nový prvek vizuálního stylu ze zadaných hodnot třídy, části a stavu. |
| Equals(Object) |
Určí, zda se zadaný objekt rovná aktuálnímu objektu. (Zděděno od Object) |
| GetHashCode() |
Slouží jako výchozí hashovací funkce. (Zděděno od Object) |
| GetType() |
Type Získá z aktuální instance. (Zděděno od Object) |
| MemberwiseClone() |
Vytvoří mělkou kopii aktuálního Objectsouboru . (Zděděno od Object) |
| ToString() |
Vrátí řetězec, který představuje aktuální objekt. (Zděděno od Object) |
