Question

I am trying to delete selected text from textbox and enter new character in place of it.
For example, if textbox consists of 123456 and I select 345, and press r on the keyboard, it should replace the selected text.

here is my code:

string _selectText = txtCal.SelectedText;
string _text = Convert.ToString(btn.Text);

if (_selectText.Length > 0) {
   int SelectionLenght = txtCal.SelectionLength;
   string SelectText = txtCal.Text.Substring(txtCal.SelectionStart, SelectionLenght);
   txtCal.Text = ReplaceMethod(SelectText, _text);
}

//replace method function
public string ReplaceMethod(string replaceString, string replaceText) {
   string newText = txtCal.Text.Replace(replaceString, replaceText);
   return newText;
}

Can anyone show me where my mistake is?

Answer 1

Try this instead

if (textbox1.SelectedText.Length > 0)
{
   textbox1.Text = textbox1.Text.Replace(text1.Text.Substring(textbox1.SelectionStart, textbox1.SelectionLength), btn.Text);                
}