ExtendedProperties.DoesPropertyExist 方法

指示指定的 ExtendedProperty 对象是否存在于 ExtendedProperties 集合中。

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

语法

声明
Public Function DoesPropertyExist ( _
    id As Guid _
) As Boolean
用法
Dim instance As ExtendedProperties
Dim id As Guid
Dim returnValue As Boolean

returnValue = instance.DoesPropertyExist(id)

public bool DoesPropertyExist(
    Guid id
)

public:
bool DoesPropertyExist(
    Guid id
)

public boolean DoesPropertyExist(
    Guid id
)

public function DoesPropertyExist(
    id : Guid
) : boolean

参数

• id
  类型：System.Guid
  要检查的属性的全局唯一标识符 (GUID)。

返回值

类型：System.Boolean
如果指定的 ExtendedProperty 对象存在于 ExtendedProperties 集合中，则为 true；否则为 false。

示例

此示例演示如何订阅 CursorDown 事件和 Stroke 事件来计算用户创建笔画所用的时间长度。

在笔画开始时，会激发 CursorDown 事件。当前时间会放置在 Stroke 对象的 ExtendedProperties 集合中。

Private Sub mInkObject_CursorDown(ByVal sender As Object, ByVal e As InkCollectorCursorDownEventArgs)
    ' add extended property indicating the time the stroke started
    ' STROKE_START_GUID is class level string via GUID generator
    e.Stroke.ExtendedProperties.Add(New Guid(STROKE_START_GUID), DateTime.Now)
End Sub

private void mInkObject_CursorDown(object sender, InkCollectorCursorDownEventArgs e)
{
    // add extended property indicating the time the stroke started
    // STROKE_START_GUID is class level string via GUID generator
    e.Stroke.ExtendedProperties.Add(new Guid(STROKE_START_GUID), DateTime.Now);
}

笔画完成时，会激发 Stroke 事件。起始时间是从 Stroke 对象的 ExtendedProperties 集合中获取的，可用于计算所用的时间。

Private Sub mInkObject_Stroke1(ByVal sender As Object, ByVal e As InkCollectorStrokeEventArgs)
    ' check to see if extended property for start time exists
    ' Attempting to access an extended property that hasn't been created throws an exception
    ' STROKE_START_GUID is class level string via GUID generator
    If (e.Stroke.ExtendedProperties.DoesPropertyExist(New Guid(STROKE_START_GUID))) Then

        Dim startTime As DateTime = DirectCast(e.Stroke.ExtendedProperties(New Guid(STROKE_START_GUID)).Data, DateTime)
        Dim endTime As DateTime = DateTime.Now
        Dim span As TimeSpan = New TimeSpan(endTime.Ticks - startTime.Ticks)

        ' add extended property indicating the time the stroke ended
        ' STROKE_END_GUID is class level string via GUID generator
        e.Stroke.ExtendedProperties.Add(New Guid(STROKE_END_GUID), endTime)

        ' display the number of seconds in creating this stroke
        Me.statusLabelStrokeTime.Text = span.TotalSeconds.ToString()
    End If
End Sub

private void mInkObject_Stroke1(object sender, InkCollectorStrokeEventArgs e)
{
    // check to see if extended property for start time exists
    // Attempting to access an extended property that hasn't been created throws an exception
    // STROKE_START_GUID is class level string via GUID generator
    if (e.Stroke.ExtendedProperties.DoesPropertyExist(new Guid(STROKE_START_GUID)))
    {
        DateTime startTime = (DateTime)e.Stroke.ExtendedProperties[new Guid(STROKE_START_GUID)].Data;
        DateTime endTime = DateTime.Now;
        TimeSpan span = new TimeSpan(endTime.Ticks - startTime.Ticks);

        // add extended property indicating the time the stroke ended
        // STROKE_END_GUID is class level string via GUID generator
        e.Stroke.ExtendedProperties.Add(new Guid(STROKE_END_GUID), endTime);

        // display the number of seconds in creating this stroke
        this.statusLabelStrokeTime.Text = span.TotalSeconds.ToString();
    }
}

平台

Windows Vista

.NET Framework 和 .NET Compact Framework 并不是对每个平台的所有版本都提供支持。有关支持的版本的列表，请参见.NET Framework 系统要求。

版本信息

.NET Framework

受以下版本支持：3.0

另请参见

参考

ExtendedProperties 类

ExtendedProperties 成员

Microsoft.Ink 命名空间