使用文本框中的关键字从网址中搜索原始文本

我和我的好友木琴已经在这里工作了几个小时,无法弄清楚,任何帮助将不胜感激。我基本上是想从该URL读取所有文本并搜索关键字。

if (comboBoxEdit1.Text == "Hello")
{
    label2.Text = "Current Status: Searching...";
    this.dataGridView3.ScrollBars = ScrollBars.None;
    this.dataGridView3.MouseWheel += new MouseEventHandler(mousewheel);
    dataGridView3.Rows.Clear();
    string line;
    int row = 0;
    List<String> LinesFound = new List<string>();
    StreamReader file = new StreamReader("https://pastebin.com/raw/fWxKdRjN");
    while ((line = file.ReadLine()) != null)
    {
        if (line.Contains(textEdit1.Text))
        {
            string[] Columns = line.Split(':');
            dataGridView3.Rows.Add(line);
            for (int i = 0; i < Columns.Length; i++)
            {
                dataGridView3[i, row].Value = Columns[i];
            }
            row++;
            label2.Text = "Current Status: " + dataGridView3.Rows.Count + "  Matche(s) Found";
        }
        else if (dataGridView3.RowCount == 0)
        {
            label2.Text = "Current Status: No Matche(s) Found";
        }
    }
}