Question

As part of this assignment for my class, in which I have a listbox which is connected to a database and it displays the first and last name of the students. I have also created a search feature in which the user types in the first and/or last name they are looking for in a textbox and when they press the “search” button it displays the filtered results appear in the listbox.

The last part of the question asks me to detect when the user clears the textbox, to once again display the original data in the listbox. I have the data in a method called databaseload()and so it is really down to how to I get my program to detect that the listbox is once again empty.

I found a couple of things online, and when I tried them, it didn’t work.

private void searchTextBox_KeyPress(object sender, KeyPressEventArgs e){
  if (e.KeyChar == 8)
  {
    databaseload();
  }
}

and I have also tried KeyDown

I also don’t want it to reload when first backspace is detected. I want it to reload the listbox when the searchTextBox has nothing in it.

Your help is greatly appreciated.

Answer 1

There is a TextChanged event which seems more appropriate than manually detecting backspaces. The delete key can remove all the text as well, or someone might just highlight all of the text and cut it to the Clipboard.

Example of using the TextChanged event:

private void textBox_TextChanged(object sender, EventArgs e)
{
    if (string.IsNullOrEmpty(((TextBox)sender).Text))
    {
            // reload database
    }
}