RichTextBox撤消添加空格

我已经为RichTextBox创建了我自己的撤消系统，因此无论何时您执行某项操作时撤消操作都会添加到堆栈中，并且当您按下撤消操作时，此操作将被撤消。RichTextBox撤消添加空格

此行为完全适用于我为其实施的所有控件，RichTextBoxes除外。我已经将系统简化为最简单的元素，无论何时按下delete，它都会将当前选定的文本及其索引添加到堆栈中，并且在撤消此操作时，会将文本放回到此索引处。

这里是剥离出来的简单元素的代码（如文本文件的实际读取）：

// Struct I use to store undo data 
public struct UndoSection 
{ 
    public string Undo; 
    public int Index; 

    public UndoSection(int index, string undo) 
    { 
     Index = index; 
     Undo = undo; 
    } 
} 

public partial class Form1 : Form 
{ 
    // Stack for holding Undo Data 
    Stack<UndoSection> UndoStack = new Stack<UndoSection>(); 

    // If delete is pressed, add a new UndoSection, if ctrl+z is pressed, peform undo. 
    private void Form1_KeyDown(object sender, KeyEventArgs e) 
    { 
     if (e.Modifiers == Keys.None && e.KeyCode == Keys.Delete) 
      UndoStack.Push(new UndoSection(textBox1.SelectionStart, textBox1.SelectedText)); 
     else if (e.Control && e.KeyCode == Keys.Z) 
     { 
      e.Handled = true; 
      UndoMenuItem_Click(textBox1, new EventArgs()); 
     } 
    } 

    // Perform undo by setting selected text at stored index. 
    private void UndoMenuItem_Click(object sender, EventArgs e) 
    { 
     if (UndoStack.Count > 0) 
     { 
        // Save last selection for user 
      int LastStart = textBox1.SelectionStart; 
      int LastLength = textBox1.SelectionLength; 

      UndoSection Undo = UndoStack.Pop(); 

      textBox1.Select(Undo.Index, 0); 
      textBox1.SelectedText = Undo.Undo; 

      textBox1.Select(LastStart, LastLength); 
     } 
    } 
}

不过，如果你只选择从一条线的\ n和下面更多的文字是这样： alt text ，然后按删除，然后撤消，它似乎撤消这个\ n字符两次。