自动更改 C# 窗体中的标签

>我在 C# Windows 窗体中有一个窗体，每次单击按钮时，我都会更改索引，并且我想基于此索引更改标签的内容。我找到的唯一选择是label_click但是我希望更改是自动的。对此有任何想法吗？

    // lines a gloab list of strings and index changes from a button click
    private void label1_Click(object sender, EventArgs e)
    {
        label1.Text = "videos/" + lines[index] + ".mp4"; 
    }
    private void button4_Click(object sender, EventArgs e)
    {
        index++;
    }
    private void button3_Click(object sender, EventArgs e)
    {
        if (index >= 1)
            index--;
    } 

List<string> lines = new List<string>(){/*initialization here*/}
int index = 0;
private void button4_Click(object sender, EventArgs e)
{
    //Ensure index is inside List bounds.
    index = Math.Min(lines.length -1 , index + 1);
    ChangeLabelText()
}
private void button3_Click(object sender, EventArgs e)
{
   //Ensure index is inside List bounds.
   index = Math.Max(0 , index - 1);
   ChangeLabelText()
} 
void ChangeLabelText() => label1.Text = "videos/" + lines[index] + ".mp4";