c#textbox怎么获取多个文本同时修改？（修改规则相同）

private void textBox1_DragDrop(object sender, DragEventArgs e)
{
string path = ((System.Array)e.Data.GetData(DataFormats.FileDrop)).GetValue(0).ToString();
textBox1.Text = path;
}

    private void button1_Click(object sender, EventArgs e)
    {
        string path = @textBox1.Text;
        FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read);
        StreamReader read = new StreamReader(fs, Encoding.Default);
        FileStream fs1 = new FileStream(@"C:\Users\Administrator\Desktop\test1.txt", FileMode.CreateNew, FileAccess.Write);
        StreamWriter sw = new StreamWriter(fs1);
        string str;
        int seed = 1;
        while ((str = read.ReadLine()) != null)
        {
            if (str.Contains("Capacitance :"))
            {
                int ii = str.IndexOf("Capacitance :");
                string leftstring = str.Substring(0, ii + 13);
                string rightstring = str.Substring(ii + 13 + 4, str.Length - ii - 13 - 4);
                //Thread.Sleep(10);
                seed++;
                int rrrandom = (int)(new Random(seed).Next(10, 95));
                string newstring = leftstring + " " + rrrandom + rightstring;
                sw.WriteLine(newstring);
            }
            else
            {
                sw.WriteLine(str);
            }
        }
        sw.Flush();
        fs.Close();
        read.Close();
    }

多个文本是指选择多个文本文件嘛 ?? 设置OpenFileDialog的 Multiselect = true; 可以多选; 通过
.FileNames
可以获取文件名数组;循环遍历就成了