c# 打开文件自动保存路径

        //装载文件
       private void button4_Click(object sender, EventArgs e)
       {
           OpenFileDialog openFileDialog = new OpenFileDialog();
           openFileDialog.InitialDirectory = "c:\";
           openFileDialog.Filter = "文本文件|*.*|C#文件|*.cs|所有文件|*.*";
           openFileDialog.RestoreDirectory = true;
           openFileDialog.FilterIndex = 1;
           if (openFileDialog.ShowDialog() == DialogResult.OK)
           {
   
           }
       }

 自动保存路径到配置文件

 //装载文件
       private void button4_Click(object sender, EventArgs e)
       {
           string strPath = "";
           //判断配置文件是否存在
           string str = System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase;
           str += "Config.ini";
           if (File.Exists(str))//如果配置文件存在
           {
              StreamReader sr = new StreamReader(str, Encoding.GetEncoding("gb2312"));
              strPath = sr.ReadToEnd();
              sr.Close();
           }
           else
           {
               strPath = "C:\";
           }

           OpenFileDialog openFileDialog = new OpenFileDialog();
           openFileDialog.InitialDirectory = strPath;
           openFileDialog.Filter = "文本文件|*.*|C#文件|*.cs|所有文件|*.*";
           openFileDialog.RestoreDirectory = true;
           openFileDialog.FilterIndex = 1;
           if (openFileDialog.ShowDialog() == DialogResult.OK)
           {
               //存取路径
               strPath = System.IO.Path.GetDirectoryName(openFileDialog.FileName);//得到路径
               strPath += "\";
              
                //把txt清空
               FileStream stream = File.Open(str, FileMode.OpenOrCreate, FileAccess.Write);
                stream.Seek(0, SeekOrigin.Begin);
                stream.SetLength(0);
                stream.Close();
                //向txt里面追加信息
                StreamWriter sw = new StreamWriter(str, true, Encoding.GetEncoding("gb2312"));
                sw.WriteLine(strPath);
                sw.Flush();
                sw.Close(); 
           }
           else
           {
              
           }
       }