(已解决)IO异常 进程无法访问该文件，因为它正在被另一个进程使用

Question

I'm trying to delete a line from a txt file with my program, but the program has the text file open so I can't. What do I do?

 private void btnDeleteTransaction_Click(object sender, EventArgs e)
        {
            string line = null;
            string delete = txtDeleteTransId.Text;

            using (reader = new StreamReader(txtFilePath.Text))
            {
               try { 
                using (writer = new StreamWriter(txtFilePath.Text, true))
                {
                    while ((line = reader.ReadLine()) != null)
                    {
                        if (String.Compare(line + "|", delete) == 0)
                            continue;

                        writer.WriteLine(line);
                    }
                }
            }
            catch (Exception ex)
            {
                txtMessages.Text = "exception deleting transaction: " + ex.Message;
            }
        }
        }

Figured it out below.

Answer 1

I'm dumb and was trying to write from the reader which you can't do. Here is my working code if anyone is as new as me.

    private void btnDeleteTransaction_Click(object sender, EventArgs e)
        {
            List<string> records = new List<string>();
            found = false;
            using (reader = new StreamReader(txtFilePath.Text))
            {
                while (!reader.EndOfStream)
                {
                    record = reader.ReadLine();
                    if (record.StartsWith(txtDeleteTransId.Text + "|"))
                    {
                        found = true;
                    }
                    else
                    {
                        records.Add(record);
                    }

                }
                if (!found)
                {
                    txtMessages.Text = "Record ID was not found";
                    return;
                }
            }
                try
                {
                    using (writer = new StreamWriter(txtFilePath.Text, false))
                    {
                        foreach (var item in records)
                        {
                            writer.WriteLine(item);
                        }
                    }
                    txtMessages.Text = "Record deleted";
                }
                catch (Exception ex)
                {

                    txtMessages.Text = "exception deleting record: " + ex.Message;
                }

            }
    ```