Question

以下所有代码都会删除TextBox中的所有空行。
但是我希望单击按钮时光标指针线被移除。

'First method
TextBox2.Lines = TextBox2.Lines.Where(Function(l) Not String.IsNullOrWhiteSpace(l)).ToArray()
Dim count = TextBox2.Lines.Length

'Second method
Dim tmp() As String = TextBox2.Text.Split(CChar(vbNewLine))
TextBox2.Clear()
For Each line As String In tmp
    If line.Length > 1 Then
        TextBox2.AppendText(line & vbNewLine)
    End If
Next

'Third method
Dim SearchIn = Me.TextBox2.Text
Dim sb As StringBuilder = New StringBuilder(SearchIn)
Me.TextBox2.Text = sb.Replace(vbCrLf + vbCrLf, vbCrLf).ToString

'Fourth method
TextBox2.Text = Regex.Replace(TextBox2.Text, "(?<Text>.*)(?:[\r\n]?(?:\r\n)?)", "${Text} ") + "/n"

TextBox2.Text = Replace(TextBox2.Text, vbCrLf & vbCrLf, vbCrLf)

Answer 1

要从TextBoxBase派生控件（TextBox，RichTextBox）中删除一行文本，首先必须确定正确的行。

如果包含文本，则无法使用.Lines属性，因为它将返回相对于未包装文本的行号。

您可以使用GetLineFromCharIndex()获取当前包装的行。 Integer参数是当前插入符号位置，由SelectionStart属性引用。

此行的第一个字符索引由GetFirstCharIndexFromLine()后退。

然后，找到当前行长度，识别第一个换行符。添加换行符号的长度以将其包含在计算长度中。

请注意，TextBox控件使用Environment.Newline生成换行符（＆＃34; \r\n＆＃34;），而RichTextBox控件仅使用换行符（＆＃34; \n＆＃34）。

这将删除插入符号当前所在的任何行：
（如果您只想删除空白行，请检查行长度是否为< 3）。

Dim CurrentPosition As Integer = TextBox2.SelectionStart
Dim CurrentLine As Integer = TextBox2.GetLineFromCharIndex(CurrentPosition)
Dim LineFirstChar As Integer = TextBox2.GetFirstCharIndexFromLine(CurrentLine)
Dim LineLenght As Integer = TextBox2.Text.
                            IndexOf(Environment.NewLine, LineFirstChar) - LineFirstChar +
                            Environment.NewLine.Length
If LineLenght <= 0 Then Return

TextBox2.Select(LineFirstChar, LineLenght)
TextBox2.SelectedText = TextBox2.SelectedText.Remove(0)
TextBox2.SelectionLength = 0
TextBox2.SelectionStart = If(CurrentPosition < TextBox2.Text.Length, LineFirstChar, TextBox2.Text.Length)
TextBox2.Focus()

这将删除包含插入符号的整个段落：

Dim CurrentPosition As Integer = TextBox2.SelectionStart
Dim ParagraphFirstIndex As Integer = TextBox2.Text.
                                     LastIndexOf(Environment.NewLine, CurrentPosition) +
                                                 Environment.NewLine.Length
Dim LineFeedPosition As Integer = TextBox2.Text.IndexOf(Environment.NewLine, ParagraphFirstIndex)
LineFeedPosition = If(LineFeedPosition > -1, LineFeedPosition + Environment.NewLine.Length, TextBox2.Text.Length)

Dim LineLenght As Integer = LineFeedPosition - ParagraphFirstIndex
If LineLenght <= 0 Then Return

TextBox2.Select(ParagraphFirstIndex, LineLenght)
TextBox2.SelectedText = TextBox2.SelectedText.Remove(0)
TextBox2.SelectionLength = 0
TextBox2.SelectionStart = If((CurrentPosition < TextBox2.Text.Length), ParagraphFirstIndex, TextBox2.Text.Length)
TextBox2.Focus()

删除光标所在的文本行

1 个答案: