How to Prevent Overwriting When Writing Data to a CSV File in C#?

Writing CSV files in C#: Solving the overwriting problem

When writing a CSV file in C#, a common problem is that only the last row is written. This is because each iteration of the loop overwrites the existing content in the file.

To solve this problem, each row must be appended to the CSV file instead of overwriting it. To do this, create a StringBuilder object and append new lines to it in a loop. After the loop completes, the entire StringBuilder's contents are written to a CSV file.

The following is an example of a corrected function:

<code class="language-csharp">var csv = new StringBuilder();
string first = reader[0].ToString();
string second = image.ToString();
csv.AppendLine(string.Format("{0},{1}", first, second));
File.WriteAllText(filePath, csv.ToString());</code>

Alternatively, you can use the File.AppendAllText method:

<code class="language-csharp">string newLine = string.Format("{0},{1}", first, second);
File.AppendAllText(filePath, newLine);</code>

This will append new lines to the existing file without overwriting its contents.

Another way to write a CSV file is to use the CsvHelper library. This library simplifies this process by handling type conversions, string escaping, and other complexities associated with CSV files.

The above is the detailed content of How to Prevent Overwriting When Writing Data to a CSV File in C#?. For more information, please follow other related articles on the PHP Chinese website!