C#的comboBox控件怎么用removeat()删除选定的项,代码是???

怎么删除combo box 选定的项，且txt文档里面也删除所选那条

//单击某一项时，删除该项
 private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
   {
        //获取comboBox1所选项的索引
         int  selectIndex=comboBox1.SelectedIndex;
            //移除所选项
          comboBox1.Items.RemoveAt(selectIndex);
    }

txt文档也删除是什么意思

//单击值为0 的选择项后，移除该项

//单击某一项时，删除该项
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
//获取comboBox1所选项的索引
int selectIndex=comboBox1.SelectedIndex;
//移除所选项
comboBox1.Items.RemoveAt(selectIndex);
}

RemoveAt（索引）