TextPointer.GetPositionAtOffset 方法

  • 参考

定义

命名空间:
System.Windows.Documents
程序集:
PresentationFramework.dll

返回一个 TextPointer，它指向从内容开始位置计算的由指定偏移量（以符号数为单位）指示的位置。

重载

GetPositionAtOffset(Int32, LogicalDirection)

返回一个 TextPointer，它指向从当前 TextPointer 的开始位置沿指定方向计算的由指定偏移量（以符号数为单位）指示的位置。
GetPositionAtOffset(Int32)

返回一个 TextPointer，它指向从当前 TextPointer 的开始位置计算的由指定偏移量（以符号数为单位）指示的位置。

GetPositionAtOffset(Int32, LogicalDirection)

返回一个 TextPointer，它指向从当前 TextPointer 的开始位置沿指定方向计算的由指定偏移量（以符号数为单位）指示的位置。

public:
 System::Windows::Documents::TextPointer ^ GetPositionAtOffset(int offset, System::Windows::Documents::LogicalDirection direction);
public System.Windows.Documents.TextPointer GetPositionAtOffset (int offset, System.Windows.Documents.LogicalDirection direction);
member this.GetPositionAtOffset : int * System.Windows.Documents.LogicalDirection -> System.Windows.Documents.TextPointer
Public Function GetPositionAtOffset (offset As Integer, direction As LogicalDirection) As TextPointer

参数

offset
Int32

偏移量（以符号数为单位），使用它计算并返回位置。 如果偏移量为负，则返回的 TextPointer 位于当前 TextPointer 之前；否则，位于它之后。

direction
LogicalDirection

LogicalDirection 值之一，它指定返回的 TextPointer 的逻辑方向。

返回

TextPointer

一个指向由指定偏移量指示的位置的 TextPointer；或者，如果偏移量超过了内容的结束位置，则为 null。

注解

以下任一项被视为符号：

另请参阅

适用于

GetPositionAtOffset(Int32)

返回一个 TextPointer，它指向从当前 TextPointer 的开始位置计算的由指定偏移量（以符号数为单位）指示的位置。

public:
 System::Windows::Documents::TextPointer ^ GetPositionAtOffset(int offset);
public System.Windows.Documents.TextPointer GetPositionAtOffset (int offset);
member this.GetPositionAtOffset : int -> System.Windows.Documents.TextPointer
Public Function GetPositionAtOffset (offset As Integer) As TextPointer

参数

offset
Int32

偏移量（以符号数为单位），使用它计算并返回位置。 如果偏移量为负，则在与 LogicalDirection 属性指示的方向相反的逻辑方向上计算位置。

返回

TextPointer

一个指向由指定偏移量指示的位置的 TextPointer；或者，如果找不到对应位置，则为 null。

示例

以下示例演示了此方法的用法。 此示例使用 GetPositionAtOffset 该方法实现一对方法，一个方法计算相对于任何宿主段落的指定位置的偏移量，另一 TextPointer 个方法返回指定段落中的指定偏移量。

// Returns the offset for the specified position relative to any containing paragraph.
int GetOffsetRelativeToParagraph(TextPointer position)
{
    // Adjust the pointer to the closest forward insertion position, and look for any
    // containing paragraph.
    Paragraph paragraph = (position.GetInsertionPosition(LogicalDirection.Forward)).Paragraph;

    // Some positions may be not within any Paragraph; 
    // this method returns an offset of -1 to indicate this condition.
    return (paragraph == null) ? -1 : paragraph.ContentStart.GetOffsetToPosition(position);
}

// Returns a TextPointer to a specified offset into a specified paragraph. 
TextPointer GetTextPointerRelativeToParagraph(Paragraph paragraph, int offsetRelativeToParagraph)
{
    // Verify that the specified offset falls within the specified paragraph.  If the offset is
    // past the end of the paragraph, return a pointer to the farthest offset position in the paragraph.
    // Otherwise, return a TextPointer to the specified offset in the specified paragraph.
    return (offsetRelativeToParagraph > paragraph.ContentStart.GetOffsetToPosition(paragraph.ContentEnd)) 
        ? paragraph.ContentEnd : paragraph.ContentStart.GetPositionAtOffset(offsetRelativeToParagraph);
}

' Returns the offset for the specified position relative to any containing paragraph.
Private Function GetOffsetRelativeToParagraph(ByVal position As TextPointer) As Integer
    ' Adjust the pointer to the closest forward insertion position, and look for any
    ' containing paragraph.
    Dim paragraph As Paragraph = (position.GetInsertionPosition(LogicalDirection.Forward)).Paragraph

    ' Some positions may be not within any Paragraph 
    ' this method returns an offset of -1 to indicate this condition.
    Return If((paragraph Is Nothing), -1, paragraph.ContentStart.GetOffsetToPosition(position))
End Function

' Returns a TextPointer to a specified offset into a specified paragraph. 
Private Function GetTextPointerRelativeToParagraph(ByVal paragraph As Paragraph, ByVal offsetRelativeToParagraph As Integer) As TextPointer
    ' Verify that the specified offset falls within the specified paragraph.  If the offset is
    ' past the end of the paragraph, return a pointer to the farthest offset position in the paragraph.
    ' Otherwise, return a TextPointer to the specified offset in the specified paragraph.
    Return If((offsetRelativeToParagraph > paragraph.ContentStart.GetOffsetToPosition(paragraph.ContentEnd)), paragraph.ContentEnd, paragraph.ContentStart.GetPositionAtOffset(offsetRelativeToParagraph))
End Function

注解

以下任一项被视为符号：

另请参阅

适用于