Removing text from RichTextBox is not working-CodePudding

I am trying to remove characters from current cursor position to start of the string. It's working fine in simple TextBox

if (e.KeyCode == Keys.F2)
            {
                int LineNumber = txtDescription___.GetLineFromCharIndex(txtDescription___.SelectionStart);
                txtDescription___.Text = txtDescription___.Text.Remove(0, txtDescription___.SelectionStart - 0);
            }

But when I am trying to execute this code with RichTextBox it works on Text not on RTF and removes all styles. So I tried this code

if (e.KeyCode == Keys.F2)
            {
                int LineNumber = txtDescription___.GetLineFromCharIndex(txtDescription___.SelectionStart);
                txtDescription___.Rtf = txtDescription___.Rtf.Remove(0, txtDescription___.SelectionStart - 0);
            }

Now It's showing the following error File Format is not valid Can someone suggest me. How can I perform same code with RTF?

CodePudding user response：

Try the below code,

if (e.KeyCode == Keys.F2)
{
    int began = rtbDescription___.SelectionStart;
    rtbDescription___.SelectionLength = began;
    rtbDescription___.SelectedText = "";
}