在C＃中使用StreamWriter时，请编写以.csv或Excel文件分隔的其他选项卡或文件

Question

I have a console application that outputs the result into a .csv file. The console application calls several web services and outputs several data. The output contain URLs which differentiate one site from another other. The code works fine, but the output is in one big CSV file and it gets divided when it reaches the header then starts writing the data from the new site.

Here you have how the output is now from the CSV file:

ProjectTitle,PublishStatus,Type,NumberOfUsers, URL
Project one,published,Open,1,http://localhost/test1
Project two,expired,Closed,14,http://localhost/test1

ProjectTitle,PublishStatus,Type,NumberOfUsers,URL
Project one V2,expired,Closed,2,http://localhost/test2
Project two V2,Published,Open,3,http://localhost/test2

What I am trying to do its to either output the first set of data (depending on each URL) and then the second set of data in a different tab in Excel, or just create a new file for the new set of data. My code:

public static XmlDocument xml = new XmlDocument();

static void Main(string[] args)
{
    xml.Load("config.xml");
    test();            
}

private static void test()
{

List<string> url = new List<string>();
int count = xml.GetElementsByTagName("url").Count;

for (int i = 0; i < count; ++i)
{
    url.Add(xml.GetElementsByTagName("url")[i].InnerText);

    Url = url[i];               

}

string listFile = "ListOfSites";
string outCsvFile = string.Format(@"C:\\testFile\\{0}.csv", testFile + DateTime.Now.ToString("_yyyyMMdd HHmms"));


using (FileStream fs = new FileStream(outCsvFile, FileMode.Append, FileAccess.Write))                    
using (StreamWriter file = new StreamWriter(fs))

file.WriteLine("ProjectTitle,PublishStatus,Type,NumberOfSUsers,URL");
    foreach(WS.ProjectData proj in pr.Distinct(new ProjectEqualityComparer()))
        {
            file.WriteLine("{0},\"{1}\",{2},{3},{4}",
            proj.ProjectTitle,                               
            proj.PublishStatus,                               
            proj.type,
            proj.userIDs.Length.ToString(NumberFormatInfo.InvariantInfo),
            url[i].ToString());
        }
}

Answer 1

This is a quick fix. There may be a more elegant way to accomplish this as well:

public static XmlDocument xml = new XmlDocument();

static void Main(string[] args)
{
    xml.Load("config.xml");

    // relocated from `test` method to `Main`
    List<string> url = new List<string>();
    int count = xml.GetElementsByTagName("url").Count;

    for (int i = 0; i < count; ++i)
    {
        url.Add(xml.GetElementsByTagName("url")[i].InnerText);

        Url = url[i];               
        test(Url);
    }

}

private static void test(string url)
{
    string listFile = "ListOfSites";
    string outCsvFile = string.Format(@"C:\\testFile\\{0}.csv", testFile + DateTime.Now.ToString("_yyyyMMdd HHmms"));


    using (FileStream fs = new FileStream(outCsvFile, FileMode.Append, FileAccess.Write))           
    {
        using (StreamWriter file = new StreamWriter(fs))
        {
            file.WriteLine("ProjectTitle,PublishStatus,Type,NumberOfSUsers,URL");
        foreach(WS.ProjectData proj in pr.Distinct(new ProjectEqualityComparer()))
            {
                file.WriteLine("{0},\"{1}\",{2},{3},{4}",
                proj.ProjectTitle,                               
                proj.PublishStatus,                               
                proj.type,
                proj.userIDs.Length.ToString(NumberFormatInfo.InvariantInfo),
                url);
            }
        }
    }         
}

NOTE: Please use braces in C# even if you don't NEED them. It makes your code more readable.

Answer 2

If you want to write an Excel file with different worksheets you can try and use the EpPlus library, it is open source and free.

Here is the nuget page

To generate more files, you have to decide how to name them and if the records for each file are random in the source list, you can generate different lists of output strings for different output files and use the File.AppendAllLines(filename, collection); to save the data in the different files. I don't recommend you to open and close the files for each row to write because it is a time and resource consuming operation.