PropertyGrid控件(3) 使用

概要：写一个类（主要写这个类的属性），然后将 PropertyGrid 显示这个类的属性，用 PropertyGrid.SelectedObject 来关联这个类。

Where to Use the PropertyGrid Control

There are numerous places in an application where you might want to provide a richer editing experience by having the user interact with a PropertyGrid. One example is an application that has several "settings" or options, some of them complex, that a user can set. You could use radio buttons, combo boxes, or text boxes to represent these options. Instead, this paper will step you though the process of using the PropertyGrid control to create an options window for setting application options. The OptionsDialog form that you created above will be the start of the options window. Now create a class called AppSettings that contains all of the properties that map to the application settings. The settings are much easier to manage and maintain if you create a separate class rather than using individual variables.

Public Class AppSettings
    Private _saveOnClose As Boolean = True
    Private _greetingText As String = "Welcome to your application!"
    Private _maxRepeatRate As Integer = 10
    Private _itemsInMRU As Integer = 4
    Private _settingsChanged As Boolean = False
    Private _appVersion As String = "1.0"

    Public Property SaveOnClose() As Boolean
        Get
            Return _saveOnClose
        End Get
        Set(ByVal Value As Boolean)
            _saveOnClose = Value
        End Set
    End Property
    Public Property GreetingText() As String
        Get
            Return _greetingText
        End Get
        Set(ByVal Value As String)
            _greetingText = Value
        End Set
    End Property
    Public Property ItemsInMRUList() As Integer
        Get
            Return _itemsInMRU
        End Get
        Set(ByVal Value As Integer)
            _itemsInMRU = Value
        End Set
    End Property
    Public Property MaxRepeatRate() As Integer
        Get
            Return _maxRepeatRate
        End Get
        Set(ByVal Value As Integer)
            _maxRepeatRate = Value
        End Set
    End Property
    Public Property SettingsChanged() As Boolean
        Get
            Return _settingsChanged
        End Get
        Set(ByVal Value As Boolean)
            _settingsChanged = Value
        End Set
    End Property
    Public Property AppVersion() As String
        Get
            Return _appVersion
        End Get
        Set(ByVal Value As String)
            _appVersion = Value
        End Set
    End Property
End Class

The PropertyGrid on the options window will manipulate this class, so add the class definition to your application project, either in a new file or at the bottom of the source code for the form.

Selecting an Object

To identify what the PropertyGrid displays, set the PropertyGrid.SelectedObject property to an object instance. The PropertyGrid does the rest. Each time you set SelectedObject, the PropertyGrid refreshes the properties shown. This provides an easy way to force the refresh of properties, or to switch between objects at run time. You can also call the PropertyGrid.Refresh method to refresh properties.

To continue, update the code in the OptionsDialog constructor to create an AppSettings object and set it to the PropertyGrid.SelectedObject property.

 Public Sub New()
      MyBase.New()
      OptionsPropertyGrid = New PropertyGrid()
      OptionsPropertyGrid.Size = New Size(300, 250)
      Me.Controls.Add(OptionsPropertyGrid)
      Me.Text = "Options Dialog"
      ' Create the AppSettings class and display it in the PropertyGrid.
      Dim appset as AppSettings = New AppSettings()
      OptionsPropertyGrid.SelectedObject = appset
End Sub

Compile and run the application. The following screen shot shows how it should look.

Figure 2. AppSettings class selected in the PropertyGrid

编者或作者: 我有闲    收录日期: 2008-12-21
参考或来源: 我有闲IT教程网 WoYouXian.net

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