How to search items on listbox with a text filter in C#?

See more:

C#

Visual-Studio

ListBox

search

The following code working well with basics but I would like to update with speacial request.

My_listBox.SelectedItems.Clear();

for (int i = My_listBox.Items.Count - 1; i >= 0; i--)
{
    if (My_listBox.Items[i].ToString().ToLower().Contains(My_textBox_Search.Text.ToLower()))
    {
        if (My_listBox.Items.Count == null)
        {
            MessageBox.Show("No matches found.");
        }
        else
        {
            My_listBox.SetSelected(i, true);
        }
    }
    else
    {
        My_textBox_ResultOfSearchListedData.Text = My_listBox.SelectedItems.Count.ToString();
    }

I try to add notification message when nothing found after search?

Found the right text what is selected on ListBox but how to remove anything elese from the list?

I also want keep the counter how much selected (found items) in the list?

What I have tried:

My_listBox.Items.Remove(i);
My_listBox.Items.RemoveAt(i);
My_listBox.Items.ToString().Remove(i);