TextPointer.CompareTo(TextPointer) 方法
定义
重要
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对当前 TextPointer 和第二个指定 TextPointer 所表示位置的顺序进行比较。
public:
int CompareTo(System::Windows::Documents::TextPointer ^ position);public int CompareTo (System.Windows.Documents.TextPointer position);member this.CompareTo : System.Windows.Documents.TextPointer -> intPublic Function CompareTo (position As TextPointer) As Integer参数
- position
- TextPointer
一个 TextPointer，它指定要与当前位置进行比较的位置。
返回
如果当前 TextPointer 位于 position 之前，则为 -1；如果位置相同，则为 0；如果当前 TextPointer 位于 position 之后，则为 +1。
例外
position 指定位于与当前位置相关联的文本容器之外的某个位置。
示例
以下示例演示了此方法的用法。 在此示例中，方法 CompareTo 与 方法结合使用， GetInsertionPosition 以测试指定的 TextElement 是否为空。
// Tests to see if the specified TextElement is empty (has no printatble content).
bool IsElementEmpty(TextElement element)
{
// Find starting and ending insertion positions in the element.
// Inward-facing directions are used to make sure that insertion position
// will be found correctly in case when the element may contain inline
// formatting elements (such as a Span or Run that contains Bold or Italic elements).
TextPointer start = element.ContentStart.GetInsertionPosition(LogicalDirection.Forward);
TextPointer end = element.ContentEnd.GetInsertionPosition(LogicalDirection.Backward);
// The element has no printable content if its first and last insertion positions are equal.
return start.CompareTo(end) == 0;
} // End IsEmptyElement method.
' Tests to see if the specified TextElement is empty (has no printatble content).
Private Function IsElementEmpty(ByVal element As TextElement) As Boolean
' Find starting and ending insertion positions in the element.
' Inward-facing directions are used to make sure that insertion position
' will be found correctly in case when the element may contain inline
' formatting elements (such as a Span or Run that contains Bold or Italic elements).
Dim start As TextPointer = element.ContentStart.GetInsertionPosition(LogicalDirection.Forward)
Dim [end] As TextPointer = element.ContentEnd.GetInsertionPosition(LogicalDirection.Backward)
' The element has no printable content if its first and last insertion positions are equal.
Return start.CompareTo([end]) = 0
End Function ' End IsEmptyElement method.
注解
值 -1 指示当前 TextPointer 指定的位置先于 指定 position的位置。 值为 0 表示所指示的位置相等。 正值 +1 指示当前 TextPointer 指定的位置后跟指定 position的位置。
