通用列表到 CSV 字符串

我有一个列表想要写入 CSV 字符串。

我发现的例子似乎都是针对单个项目列表，我的有多个项目。

我目前拥有的代码是；

private static string CreateCSVTextFile<T>(List<T> data, string seperator = ",") where T : ExcelReport, new()
{
  var objectType = typeof(T);
  var properties = objectType.GetProperties();
  var currentRow = 0;
  var returnString = "";
  foreach (var row in data)
  {
    var currentColumn = 0;
    var lineString = "";
    foreach (var info in properties)
    {
      lineString = lineString + info.GetValue(row, null) + seperator;
      currentColumn++;
    }
    if (seperator != "")
    {
      lineString = lineString.Substring(0, lineString.Count() - 2);
    }
    returnString = returnString + Environment.NewLine + lineString;
    currentRow++;
  }
  return returnString;
}

但当列表很大时，此方法需要很长时间才能运行。

我的列表所基于的类看起来像；

internal class ClientMasterFile
{
public String COL1{ get; set; }
public String COL2{ get; set; }
public String COL3{ get; set; }
public String COL4{ get; set; }
public String COL5{ get; set; }
public String COL6{ get; set; }
public String COL7{ get; set; }
public String COL8{ get; set; }
public String COL9{ get; set; }
public String COL10{ get; set; }
public String COL11{ get; set; }
public String COL12{ get; set; }
}

是否有使用高级版本的 String.Join 更快的方法来做到这一点？

Thanks

您的方法可以使用简化StringBuilder http://msdn.microsoft.com/en-us/library/system.text.stringbuilder.aspx and string.Join http://msdn.microsoft.com/en-us/library/System.String.Join.aspx.

直接连接字符串速度很慢并且会占用大量内存，这对于小型操作来说是很好的。

See: StringBuilder 是否比 String 连接使用更多内存？ https://stackoverflow.com/questions/4191079/does-stringbuilder-use-more-memory-than-string-concatenation

private static string CreateCSVTextFile<T>(List<T> data, string seperator = ",")
{
    var properties = typeof(T).GetProperties();
    var result = new StringBuilder();

    foreach (var row in data)
    {
        var values = properties.Select(p => p.GetValue(row, null));
        var line = string.Join(seperator, values);
        result.AppendLine(line);
    }

    return result.ToString();
}

更完整的 CSV 实现：

private static string CreateCSVTextFile<T>(List<T> data)
{
    var properties = typeof(T).GetProperties();
    var result = new StringBuilder();

    foreach (var row in data)
    {
        var values = properties.Select(p => p.GetValue(row, null))
                               .Select(v => StringToCSVCell(Convert.ToString(v)));
        var line = string.Join(",", values);
        result.AppendLine(line);
    }

    return result.ToString();
}

private static string StringToCSVCell(string str)
{
    bool mustQuote = (str.Contains(",") || str.Contains("\"") || str.Contains("\r") || str.Contains("\n"));
    if (mustQuote)
    {
        StringBuilder sb = new StringBuilder();
        sb.Append("\"");
        foreach (char nextChar in str)
        {
            sb.Append(nextChar);
            if (nextChar == '"')
                sb.Append("\"");
        }
        sb.Append("\"");
        return sb.ToString();
    }

    return str;
}

Using: 将棘手的字符串转义为 CSV 格式 https://stackoverflow.com/questions/6377454/escaping-tricky-string-to-csv-format