Procedura: creare un editor di tipo con interfaccia utente
Negli esempi di codice riportati di seguito sono inclusi due diversi editor di tipo con interfaccia utente per due proprietà del controllo FlashTrackBar descritto in Procedura: creare un controllo di Windows Form che visualizzi lo stato di avanzamento.
Nel primo esempio, la classe FlashTrackBarValueEditor viene applicata alla proprietà Value e vengono illustrati i seguenti punti:
Come FlashTrackBarValueEditor estende la classe UITypeEditor.
Come eseguire l'override del metodo EditValue per impostare le proprietà dell'editor.
Come eseguire l'override del metodo GetEditStyle per specificare lo stile dell'editor.
Nel secondo esempio, la classe FlashTrackBarDarkenByEditor estende FlashTrackBarValueEditor ed esegue l'override di un metodo di supporto per l'impostazione di proprietà. La classe FlashTrackBarDarkenByEditor viene applicata alla proprietà DarkenBy di FlashTrackBar.
Nota
È necessario compilare questi esempi insieme al controllo FlashTrackBar, come descritto in Procedura: creare un controllo di Windows Form che visualizzi lo stato di avanzamento.
FlashTrackBarValueEditor
Imports System
Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Drawing.Design
Imports System.Windows.Forms
Imports System.Diagnostics
Imports System.Windows.Forms.ComponentModel
Imports System.Windows.Forms.Design
Namespace Microsoft.Samples.WinForms.VB.FlashTrackBar
<System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
Public Class FlashTrackBarValueEditor
Inherits UITypeEditor
Private edSvc As IWindowsFormsEditorService
Overridable Protected Sub SetEditorProps(editingInstance As FlashTrackBar, editor As FlashTrackBar)
editor.ShowValue = true
editor.StartColor = Color.Navy
editor.EndColor = Color.White
editor.ForeColor = Color.White
editor.Min = editingInstance.Min
editor.Max = editingInstance.Max
End Sub
Overrides OverLoads Public Function EditValue(context As ITypeDescriptorContext, provider As IServiceProvider, value As object) As Object
If ((context IsNot Nothing) And (context.Instance IsNot Nothing) And (provider IsNot Nothing)) Then
edSvc = CType(provider.GetService(GetType(IWindowsFormsEditorService)), IWindowsFormsEditorService)
If (edSvc IsNot Nothing) Then
Dim trackBar As FlashTrackBar = New FlashTrackBar()
AddHandler trackBar.ValueChanged, AddressOf Me.ValueChanged
SetEditorProps(CType(context.Instance, FlashTrackBar), TrackBar)
Dim asInt As Boolean = True
If (TypeOf value Is Integer) Then
trackBar.Value = CInt(value)
ElseIf (TypeOf value Is System.Byte) Then
asInt = False
trackBar.Value = CType(value, Byte)
End If
edSvc.DropDownControl(trackBar)
If (asInt) Then
value = trackBar.Value
Else
value = CType(trackBar.Value, Byte)
End If
End If
End If
Return value
End Function
Overrides OverLoads Public Function GetEditStyle(context As ITypeDescriptorContext) As UITypeEditorEditStyle
If ((context IsNot Nothing) And (context.Instance IsNot Nothing)) Then
Return UITypeEditorEditStyle.DropDown
End If
Return MyBase.GetEditStyle(context)
End Function
private Sub ValueChanged(sender As object, e As EventArgs)
If (edSvc IsNot Nothing) Then
edSvc.CloseDropDown()
End If
End Sub
End Class
End Namespace
namespace Microsoft.Samples.WinForms.Cs.FlashTrackBar {
using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Design;
using System.Windows.Forms;
using System.Windows.Forms.ComponentModel;
using System.Windows.Forms.Design;
[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust")]
public class FlashTrackBarValueEditor : System.Drawing.Design.UITypeEditor {
private IWindowsFormsEditorService edSvc = null;
protected virtual void SetEditorProps(FlashTrackBar editingInstance, FlashTrackBar editor) {
editor.ShowValue = true;
editor.StartColor = Color.Navy;
editor.EndColor = Color.White;
editor.ForeColor = Color.White;
editor.Min = editingInstance.Min;
editor.Max = editingInstance.Max;
}
public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value) {
if (context != null
&& context.Instance != null
&& provider != null) {
edSvc = (IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService));
if (edSvc != null) {
FlashTrackBar trackBar = new FlashTrackBar();
trackBar.ValueChanged += new EventHandler(this.ValueChanged);
SetEditorProps((FlashTrackBar)context.Instance, trackBar);
bool asInt = true;
if (value is int) {
trackBar.Value = (int)value;
}
else if (value is byte) {
asInt = false;
trackBar.Value = (byte)value;
}
edSvc.DropDownControl(trackBar);
if (asInt) {
value = trackBar.Value;
}
else {
value = (byte)trackBar.Value;
}
}
}
return value;
}
public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context) {
if (context != null && context.Instance != null) {
return UITypeEditorEditStyle.DropDown;
}
return base.GetEditStyle(context);
}
private void ValueChanged(object sender, EventArgs e) {
if (edSvc != null) {
edSvc.CloseDropDown();
}
}
}
}
FlashTrackBarDarkenByEditor
Imports System
Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Drawing.Design
Imports System.Windows.Forms
Imports System.Diagnostics
Namespace Microsoft.Samples.WinForms.VB.FlashTrackBar
Public Class FlashTrackBarDarkenByEditor
Inherits FlashTrackBarValueEditor
Overrides Protected Sub SetEditorProps(editingInstance As FlashTrackBar, editor As FlashTrackBar)
MyBase.SetEditorProps(editingInstance, editor)
editor.Min = 0
editor.Max = System.Byte.MaxValue
End Sub
End Class
End Namespace
namespace Microsoft.Samples.WinForms.Cs.FlashTrackBar {
using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Design;
using System.Windows.Forms;
using System.Windows.Forms.ComponentModel;
using System.Windows.Forms.Design;
public class FlashTrackBarDarkenByEditor : FlashTrackBarValueEditor {
protected override void SetEditorProps(FlashTrackBar editingInstance, FlashTrackBar editor) {
base.SetEditorProps(editingInstance, editor);
editor.Min = 0;
editor.Max = byte.MaxValue;
}
}
}
Vedere anche
Attività
Procedura: implementare un editor di tipi con interfaccia utente