TextPointer.GetOffsetToPosition(TextPointer) 方法

定义

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

返回当前 TextPointer 与第二个指定 TextPointer之间的符号计数。

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

参数

position
TextPointer

一 TextPointer 个指定查找距离的位置（以符号为单位）。

返回

Int32

当前 TextPointer 和 position. 之间的符号的相对数量。 负值表示当前 TextPointer 位于指定的 position位置之后，0 表示位置相等，正值指示当前 TextPointer 位于指定 position位置之前。

例外

ArgumentException

position 指定与当前位置关联的文本容器外部的位置。

示例

以下示例演示了此方法的用法。 该示例使用 GetOffsetToPosition 该方法查找两 TextPointer 个实例的偏移量，然后使用此信息在一个 RichTextBox实例中保存和还原所选内容。 该示例假定所选内容 RichTextBox 在选择保存和选择还原之间未更改。

struct SelectionOffsets { internal int Start; internal int End; }
 
SelectionOffsets GetSelectionOffsetsRTB(RichTextBox richTextBox)
{
    SelectionOffsets selectionOffsets;
 
    TextPointer contentStart = richTextBox.Document.ContentStart;

    // Find the offset for the starting and ending TextPointers.
    selectionOffsets.Start = contentStart.GetOffsetToPosition(richTextBox.Selection.Start);
    selectionOffsets.End = contentStart.GetOffsetToPosition(richTextBox.Selection.End);

    return selectionOffsets;
}

void RestoreSelectionOffsetsRTB(RichTextBox richTextBox, SelectionOffsets selectionOffsets)
{
    TextPointer contentStart = richTextBox.Document.ContentStart;
 
    // Use previously determined offsets to create corresponding TextPointers,
    // and use these to restore the selection.
    richTextBox.Selection.Select(
       contentStart.GetPositionAtOffset(selectionOffsets.Start),
       contentStart.GetPositionAtOffset(selectionOffsets.End)
    );
}

Private Structure SelectionOffsets
    Friend Start As Integer
    Friend [End] As Integer
End Structure

Private Function GetSelectionOffsetsRTB(ByVal richTextBox As RichTextBox) As SelectionOffsets
    Dim selectionOffsets As SelectionOffsets

    Dim contentStart As TextPointer = richTextBox.Document.ContentStart

    ' Find the offset for the starting and ending TextPointers.
    selectionOffsets.Start = contentStart.GetOffsetToPosition(richTextBox.Selection.Start)
    selectionOffsets.End = contentStart.GetOffsetToPosition(richTextBox.Selection.End)

    Return selectionOffsets
End Function

Private Sub RestoreSelectionOffsetsRTB(ByVal richTextBox As RichTextBox, ByVal selectionOffsets As SelectionOffsets)
    Dim contentStart As TextPointer = richTextBox.Document.ContentStart

    ' Use previously determined offsets to create corresponding TextPointers,
    ' and use these to restore the selection.
    richTextBox.Selection.Select(contentStart.GetPositionAtOffset(selectionOffsets.Start), contentStart.GetPositionAtOffset(selectionOffsets.End))
End Sub

注解

以下任一项都被视为符号：

适用于

另请参阅