在C＃中将数据写入CSV文件

问题描述：

我试图使用C＃语言逐行写入一个 csv 文件。这是我的功能

I am trying to write into a csv file row by row using C# language. Here is my function

string first = reader[0].ToString();
string second=image.ToString();
string csv = string.Format("{0},{1}\n", first, second);
File.WriteAllText(filePath, csv);

整个函数运行在一个循环中，每一行都应写入 csv 文件。在我的情况下，下一行覆盖现有的行，最后我在最后一个csv文件中只得到单个记录。如何写入 csv 文件中的所有行。

The whole function runs inside a loop, and every row should be written to the csv file. In my case next row overwrites the existing row and in the end I am getting only single record in the csv file which is last one. How can I write all the rows in the csv file.

答

更新

我天真的天，我建议手动（这是一个简单的问题的一个简单的解决方案），但是由于这变得越来越受欢迎，我建议使用一个库进行所有安全检查等。

Back in my naïve days, I suggested doing this manually (it was a simple solution to a simple question), however due to this becoming more and more popular, I'd recommend using a library that does all the safety checks, etc.

CSV的方式比问题/答案显示。

CSV is way more complicated than what the question/answer suggests.

原始答案

由于您已经有一个循环，这样做：

As you already have a loop, consider doing it like this:

//before your loop
    var csv = new StringBuilder();

//in your loop
    var first = reader[0].ToString();
    var second = image.ToString();
    //Suggestion made by KyleMit
    var newLine = string.Format("{0},{1}", first, second);
    csv.AppendLine(newLine);  

//after your loop
    File.WriteAllText(filePath, csv.ToString());

或这样的事情。
我的推理是：您不需要为每个项目写入文件，您只会打开一次，然后写入它。

Or something to this effect. My reasoning is: you won't be need to write to the file for every item, you will only be opening the stream once and then writing to it.

您可以替换

File.WriteAllText(filePath, csv.ToString());

与

File.AppendAllText(filePath, csv.ToString());

如果你想保留以前的版本的csv在同一个文件中

if you want to keep previous versions of csv in the same file

C＃6

如果您使用c＃6.0，那么您可以执行以下

If you are using c# 6.0 then you can do the following

var newLine = $"{first},{second}"

编辑

这是一个 Environment.NewLine 做的

在C＃中将数据写入CSV文件

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