Question

以下代码将结果输出到csv文件。假设'valueDataList'中有10个值...当运行它时，只有一行输出到该文件。如何循环代码以在“valueDataList”中“一次”打印所有值的文件。

   foreach (var value in valueDataList)

    {
        var value1 = xxxxxxx    // this value is set here based on a query.. 
        int value2 = xxxxxxxx   // this value is set here based on a query.. 

        byte[] content;

        using (var ms = new MemoryStream())  
           {
              using (var writer = new StreamWriter(ms))
                {
                  writer.WriteLine("ValueHeading1   " + " ValueHeading2");
                  writer.WriteLine(value1 + "              " + value2);                         
                }
                  content = ms.ToArray();
                  return File(content, "text/csv", "demo.csv");
           }
    }

基本上我希望能够在每次循环迭代时追加到现有的csv文件。我怎样才能做到这一点？谢谢你的帮助。

Answer 1

你的意思是你想要将valueDataList中的所有行写入csv文件吗？如果是的话;

using (var ms = new MemoryStream())  
using (var writer = new StreamWriter(ms))
{
    writer.WriteLine("ValueHeading1   " + " ValueHeading2");

    foreach (var value in valueDataList)
    {
        var value1 = xxxxxxx    // this value is set here based on a query.. 
        int value2 = xxxxxxxx   // this value is set here based on a query.. 

        writer.WriteLine(value1 + "              " + value2);                         
    }   

    byte[] content = ms.ToArray();
    return File(content, "text/csv", "demo.csv");
}

Answer 2

File.AppendText(...)怎么样？

我在看这个作为参考：

http://www.4guysfromrolla.com/articles/072303-1.2.aspx

在文件末尾附加输出 - 如何？

2 个答案: