删除.NET RichTextBox中的特定行

Question

如何删除RichTextBox中的特定文本行？

Answer 1

另一个解决方案：

private void DeleteLine(int a_line)
{
    int start_index = richTextBox.GetFirstCharIndexFromLine(a_line);
    int count = richTextBox.Lines[a_line].Length;

    // Eat new line chars
    if (a_line < richTextBox.Lines.Length - 1)
    {
        count += richTextBox.GetFirstCharIndexFromLine(a_line + 1) -
            ((start_index + count - 1) + 1);
    }

    richTextBox.Text = richTextBox.Text.Remove(start_index, count);
}

Answer 2

这也可以解决问题（如果您可以处理表单代码中的++之类的东西）。保持文本格式。只需记住“ ReadOnly”属性对您和用户均有效。

richTextBox.SelectionStart = richTextBox.GetFirstCharIndexFromLine(your_line);
richTextBox.SelectionLength = this.richTextBox.Lines[your_line].Length+1;
this.richTextBox.SelectedText = String.Empty;

Answer 3

尝试一下：

Dim lst As New ListBox  
        Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click  
            Me.Controls.Add(lst)  
            For Each cosa As String In Me.RichTextBox1.Lines  
                lst.Items.Add(cosa)  
            Next  
            lst.Items.RemoveAt(2) 'the integer value must be the line that you want to remove -1  
            Me.RichTextBox1.Text = String.Empty  
            For i As Integer = 0 To lst.Items.Count - 1  
                If Me.RichTextBox1.Text = String.Empty Then  
                    Me.RichTextBox1.Text = lst.Items.Item(i)  
                Else  
                    MeMe.RichTextBox1.Text = Me.RichTextBox1.Text & Environment.NewLine & lst.Items.Item(i).ToString  
                End If  
            Next  
        End Sub

http://social.msdn.microsoft.com/Forums/en-US/vbgeneral/thread/63647481-743d-4e55-9043-e0db5106a03a/

Answer 4

我不知道是否有一种简单的方法可以一步完成。您可以在富文本框的.Text属性上使用.Split函数来获取行数组

string[] lines = richTextBox1.Text.Split( "\n".ToCharArray() )

然后在删除所需的行后编写一些东西，将数组重新组装成单个文本字符串，然后将其复制回RTF文本框的.Text属性。

这是一个简单的示例：

        string[] lines = richTextBox1.Text.Split("\n".ToCharArray() );


        int lineToDelete = 2;           //O-based line number

        string richText = string.Empty;

        for ( int x = 0 ; x < lines.GetLength( 0 ) ; x++ )
        {
            if ( x != lineToDelete )
            {
                richText += lines[ x ];
                richText += Environment.NewLine;
            }
        }

        richTextBox1.Text = richText;

如果您的富文本框将超过10行，那么最好使用StringBuilder而不是字符串来构成新文本。

Answer 5

在文本范围内找到要删除的文本，找到here将文本设置为空，现在该文本从文档中消失了。

Answer 6

基于tomanu的解决方案，但没有开销

int start_index = LogBox.GetFirstCharIndexFromLine(linescount);
int count = LogBox.GetFirstCharIndexFromLine(linescount + 1) - start_index;
LogBox.Text = LogBox.Text.Remove(start_index, count);

请注意，这里的线数是线数-2。

Answer 7

这是我经过单元测试的实现。

public static void DeleteLine([NotNull] this RichTextBox pRichTextBox, int pLineIndex) {
   if (pLineIndex < 0 || pLineIndex >= pRichTextBox.Lines.Length)
      throw new InvalidOperationException("There is no such line.");

   var start = pRichTextBox.GetFirstCharIndexFromLine(pLineIndex);
   var isLastLine = pLineIndex == pRichTextBox.Lines.Length - 1;
   var nextLineIndex = pLineIndex + 1;

   var end = isLastLine
      ? pRichTextBox.Text.Length - 1
      : pRichTextBox.GetFirstCharIndexFromLine(nextLineIndex) - 1;

   var length = end - start + 1;
   pRichTextBox.Text = pRichTextBox.Text.Remove(start, length);
}

单元测试：

（使用\n而不是Environment.NewLine，因为至少对我而言，RTB会自动将\r\n替换为\n）

[TestMethod]
public void TestDeleteLine_SingleLine() {
   var rtb = new RichTextBox();
   rtb.Text = "This is line1.\n";
   rtb.DeleteLine(0);
   var expected = "";
   Assert.AreEqual(expected, rtb.Text);
}

[TestMethod]
public void TestDeleteLine_BlankLastLine() {
   var rtb = new RichTextBox();
   rtb.Text = "\n";
   rtb.DeleteLine(1);
   var expected = "\n";
   Assert.AreEqual(expected, rtb.Text);
}

[TestMethod]
public void TestDeleteLine_SingleLineNoEOL() {
   var rtb = new RichTextBox();
   rtb.Text = "This is line1.";
   rtb.DeleteLine(0);
   var expected = "";
   Assert.AreEqual(expected, rtb.Text);
}

[TestMethod]
public void TestDeleteLine_FirstLine() {
   var rtb = new RichTextBox();
   rtb.Text = "This is line1.\nThis is line2.\nThis is line3.";
   rtb.DeleteLine(0);
   var expected = "This is line2.\nThis is line3.";
   Assert.AreEqual(expected, rtb.Text);
}

[TestMethod]
public void TestDeleteLine_MiddleLine() {
   var rtb = new RichTextBox();
   rtb.Text = "This is line1.\nThis is line2.\nThis is line3.";
   rtb.DeleteLine(1);
   var expected = "This is line1.\nThis is line3.";
   Assert.AreEqual(expected, rtb.Text);
}

[TestMethod]
public void TestDeleteLine_LastLine() {
   var rtb = new RichTextBox();
   rtb.Text = "This is line1.\nThis is line2.\nThis is line3.";
   rtb.DeleteLine(2);
   var expected = "This is line1.\nThis is line2.\n";
   Assert.AreEqual(expected, rtb.Text);
}

[TestMethod]
public void TestDeleteLine_OneBlankLine() {
   var rtb = new RichTextBox();
   rtb.Text = "\n";
   rtb.DeleteLine(0);
   var expected = "";
   Assert.AreEqual(expected, rtb.Text);
}

[TestMethod]
public void TestDeleteLine_BlankLines() {
   var rtb = new RichTextBox();
   rtb.Text = "\n\n\n\n\n";
   rtb.DeleteLine(2);
   var expected = "\n\n\n\n";
   Assert.AreEqual(expected, rtb.Text);
}

[TestMethod, ExpectedException(typeof(InvalidOperationException))]
public void TestDeleteLine_Exception_BeforeFront() {
   var rtb = new RichTextBox();
   rtb.Text = "\n\n\n\n\n";
   rtb.DeleteLine(-1);
}

[TestMethod, ExpectedException(typeof(InvalidOperationException))]
public void TestDeleteLine_Exception_AfterEnd() {
   var rtb = new RichTextBox();
   rtb.Text = "\n\n";
   rtb.DeleteLine(3);
}

Answer 8

很多很好的答案，但是我发现很多都太复杂了。

string[] LinesArray = this.richTextBox1.Lines;

this.richTextBox1.Clear();

for (int line = 0; line < LinesArray.Length; line++)
{
if (!LinesArray[line].Contains("< Test Text To Remove >"))
{
this.richTextBox1.AppendText(LinesArray[line] + Environment.NewLine);
}
}

我希望这对其他人有所帮助； 0）

Answer 9

int LineToDelete = 50;
List<string> lines = richTextBox1.Lines.ToList();
lines.Remove(LineToDelete);
richTextBox1.Lines = lines.ToArray();