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TextPointer.GetPositionAtOffset Method

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Definition

Namespace:
System.Windows.Documents
Assembly:
PresentationFramework.dll

Returns a TextPointer to the position indicated by the specified offset, in symbols, from the beginning of content.

Overloads

GetPositionAtOffset(Int32, LogicalDirection)

Returns a TextPointer to the position indicated by the specified offset, in symbols, from the beginning of the current TextPointer and in the specified direction.
GetPositionAtOffset(Int32)

Returns a TextPointer to the position indicated by the specified offset, in symbols, from the beginning of the current TextPointer.

GetPositionAtOffset(Int32, LogicalDirection)

Returns a TextPointer to the position indicated by the specified offset, in symbols, from the beginning of the current TextPointer and in the specified direction.

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

Parameters

offset
Int32

An offset, in symbols, for which to calculate and return the position. If the offset is negative, the returned TextPointer precedes the current TextPointer; otherwise, it follows.

direction
LogicalDirection

One of the LogicalDirection values that specifies the logical direction of the returned TextPointer.

Returns

TextPointer

A TextPointer to the position indicated by the specified offset, or null if the offset extends past the end of the content.

Remarks

Any of the following is considered to be a symbol:

See also

Applies to

GetPositionAtOffset(Int32)

Returns a TextPointer to the position indicated by the specified offset, in symbols, from the beginning of the current TextPointer.

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

Parameters

offset
Int32

An offset, in symbols, for which to calculate and return the position. If the offset is negative, the position is calculated in the logical direction opposite of that indicated by the LogicalDirection property.

Returns

TextPointer

A TextPointer to the position indicated by the specified offset, or null if no corresponding position can be found.

Examples

The following example demonstrates a use for this method. The example uses the GetPositionAtOffset method to implement a pair of methods, one to calculate the offset to a specified position relative to any hosting paragraph, and the other to return a TextPointer to a specified offset in a specified paragraph.

// 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

Remarks

Any of the following is considered to be a symbol:

See also

Applies to