InkPicture.DesiredPacketDescription 属性

项目
11/04/2008

获取或设置对与 InkPicture 对象上所绘制的墨迹关联的数据包 方面的关注。

命名空间： Microsoft.Ink
程序集： Microsoft.Ink（在 Microsoft.Ink.dll 中）

语法

声明
<BrowsableAttribute(False)> _
Public Property DesiredPacketDescription As Guid()
用法
Dim instance As InkPicture
Dim value As Guid()

value = instance.DesiredPacketDescription

instance.DesiredPacketDescription = value

[BrowsableAttribute(false)]
public Guid[] DesiredPacketDescription { get; set; }

[BrowsableAttribute(false)]
public:
property array<Guid>^ DesiredPacketDescription {
    array<Guid>^ get ();
    void set (array<Guid>^ value);
}

/** @property */
/** @attribute BrowsableAttribute(false) */
public Guid[] get_DesiredPacketDescription()
/** @property */
/** @attribute BrowsableAttribute(false) */
public  void set_DesiredPacketDescription(Guid[] value)

public function get DesiredPacketDescription () : Guid[]
public function set DesiredPacketDescription (value : Guid[])

属性值

类型：array<System.Guid[]
Guid 对象的数组，其中每个对象都表示一个与 InkPicture 对象上绘制的墨迹关联的数据包方面。

备注

数据包说明是来自 PacketProperty 对象的 Guid 对象的数组。

默认情况下，DesiredPacketDescription 包含来自 PacketProperty 对象的 X、Y 和 NormalPressure。如果将 DesiredPacketDescription 设置为其他任何值，则还会添加 X 和 Y。例如，如果仅将 DesiredPacketDescription 设置为 ButtonPressure，则 get 返回 {X, Y, ButtonPressure}，而不只是 {ButtonPressure}。

如果 DesiredPacketDescription 设置为包括 PacketStatus 的值，则会在第三个位置添加 PacketStatus。例如，如果将 DesiredPacketDescription 设置为 (a, b, c, d, PacketStatus, e, f)，则 get 将返回 (X, Y, PacketStatus, a, b, c, d, e, f)。

在多 Tablet 模式中，这是所有 Tablet 设备的数据包说明。如果任何设备不支持某个已知数据包说明属性，则不返回该属性数据。

对此属性的更改不会影响到传入的数据包数据，除非 InkEnabled 属性从 false 更改为 true。

示例

下面的示例演示如何使用 DesiredPacketDescription 属性来表示 PacketProperty 对象对特定 Guid 对象的关注，然后在 NewPackets 事件过程中使用公开的数据包属性。

首先，初始化 DesiredPacketDescription 属性，并分配事件处理程序。

' Express interest in PacketStatus, TimerTick, and NormalPressure
' X and Y will be added automatically
Dim PacketDesc As Guid() = New Guid() _
    { _
        PacketProperty.PacketStatus, _
        PacketProperty.TimerTick, _
        PacketProperty.NormalPressure _
    }

' mInkObject can be InkCollector, InkOverlay, or InkPicture
mInkObject.DesiredPacketDescription = PacketDesc
' assign event handlers
AddHandler mInkObject.CursorInRange, New InkCollectorCursorInRangeEventHandler(AddressOf mInkObject_CursorInRange)
AddHandler mInkObject.NewPackets, New InkCollectorNewPacketsEventHandler(AddressOf mInkObject_NewPackets)

// Express interest in PacketStatus, TimerTick, and NormalPressure
// X and Y will be added automatically
Guid[] PacketDesc = new Guid[] 
{
    PacketProperty.PacketStatus,
    PacketProperty.TimerTick,
    PacketProperty.NormalPressure
};
// mInkObject can be InkCollector, InkOverlay, or InkPicture
mInkObject.DesiredPacketDescription = PacketDesc;
// assign event handlers
mInkObject.CursorInRange += new InkCollectorCursorInRangeEventHandler(mInkObject_CursorInRange);
mInkObject.NewPackets += new InkCollectorNewPacketsEventHandler(mInkObject_NewPackets);

当 CursorInRange 事件激发时，将检查 InkPicture 对象是否第一次与该特定 Cursor 对象相联系。如果是，则将 DefaultDrawingAttributes 属性的复本分配给 DrawingAttributes 属性。这将确保对 DrawingAttributes 属性的后续访问不会引发 null 引用异常。

Private Sub mInkObject_CursorInRange(ByVal sender As Object, ByVal e As InkCollectorCursorInRangeEventArgs)
    Const MOUSE_CURSOR_ID As Integer = 1
    If e.NewCursor Then
        ' mInkObject can be InkCollector, InkOverlay, or InkPicture
        e.Cursor.DrawingAttributes = mInkObject.DefaultDrawingAttributes.Clone()
        ' if this cursor is the mouse, we'll set color to red
        If (MOUSE_CURSOR_ID = e.Cursor.Id) Then
            e.Cursor.DrawingAttributes.Color = Color.Red
        End If

    End If
End Sub

private void mInkObject_CursorInRange(object sender, InkCollectorCursorInRangeEventArgs e)
{
    const int MOUSE_CURSOR_ID = 1;

    if (e.NewCursor)
    {
        // mInkObject can be InkCollector, InkOverlay, or InkPicture
        e.Cursor.DrawingAttributes = mInkObject.DefaultDrawingAttributes.Clone();
        // if this cursor is the mouse, we'll set color to red
        if (MOUSE_CURSOR_ID == e.Cursor.Id)
        {
            e.Cursor.DrawingAttributes.Color = Color.Red;
        }
    }
}

当 NewPackets 事件激发时，将检查数据包数据中是否包含 NormalPressure。如果包含，则在状态标签上显示压力信息，并修改 DrawingAttributes 属性。

Private Sub mInkObject_NewPackets(ByVal sender As Object, ByVal e As InkCollectorNewPacketsEventArgs)

    ' find the NormalPressure PacketProperty
    ' Set NormalPressure to -1 if not there, as some digitizers won't support it
    Dim PacketDesc As Guid() = e.Stroke.PacketDescription
    Dim NormalPressure As Integer = -1

    For k As Integer = 0 To PacketDesc.Length - 1
        If PacketDesc(k) = PacketProperty.NormalPressure Then
            ' for simplicity, in case of multiple packets, use the first packet only
            NormalPressure = e.PacketData(k)
        End If
    Next k

    ' If we have the NormalPressure information
    ' change DrawingAttributes according to the NormalPressure
    ' Note that the change does not take effect until the next stroke
    If NormalPressure <> -1 Then
        ' display the pressure on a status label
        Me.statusLabelPressure.Text = NormalPressure.ToString()
        e.Cursor.DrawingAttributes.Width = NormalPressure * 4
        ' if pressure is above 127, change color to Red
        If NormalPressure > 127 Then
            e.Cursor.DrawingAttributes.Color = Color.Red
        Else
            e.Cursor.DrawingAttributes.Color = mInkObject.DefaultDrawingAttributes.Color
        End If
    End If

End Sub

private void mInkObject_NewPackets(object sender, InkCollectorNewPacketsEventArgs e)
{
    // find the NormalPressure PacketProperty
    // Set NormalPressure to -1 if not there, as some digitizers won't support it
    Guid[] PacketDesc = e.Stroke.PacketDescription;
    int NormalPressure = -1;
    for (int k = 0; k < PacketDesc.Length; k++)
    {
        if (PacketDesc[k] == PacketProperty.NormalPressure)
        {
            // for simplicity, in case of multiple packets, use the first packet only
            NormalPressure = e.PacketData[k];
        }
    }

    // If we have the NormalPressure information
    // change DrawingAttributes according to the NormalPressure
    // Note that the change does not take effect until the next stroke
    if (NormalPressure != -1)
    {
        // display the pressure on a status label
        this.statusLabelPressure.Text = NormalPressure.ToString();
        e.Cursor.DrawingAttributes.Width = NormalPressure * 4;
        // if pressure is above 127, change color to Red
        if (NormalPressure > 127)
        {
            e.Cursor.DrawingAttributes.Color = Color.Red;
        }
        else
        {
            e.Cursor.DrawingAttributes.Color = mInkObject.DefaultDrawingAttributes.Color;
        }
    }
}