CODEWITHSUNDEEP
c#listcsv
nemo_87
nemo_87

Reputation: 4791

Create comma separated list from list of objects

I have list of objects type Person. This class has many properties and I need them all in a comma separated list so I can use it later for Csv file.

I've managed this with foreach and adding each property, separating it with commas manual, etc.

const string commaSeparator = ",";
foreach (var item in individualsInformation)
{
    csv.AppendLine(item.ReferenceNumber + commaSeparator + item.FirstName + commaSeparator +
                   item.Surname + commaSeparator + item.MiddleName + commaSeparator +
                   item.Address1 + commaSeparator + item.Address2 + commaSeparator + 
                   item.Address3 + commaSeparator + item.Address4 + commaSeparator + 
                   item.City + commaSeparator + item.PostalCode + commaSeparator +
                   item.Country + commaSeparator + item.DateOfBirth.ToString() + commaSeparator +
                   item.ID + commaSeparator + item.Gender + commaSeparator +
                   item.Component + commaSeparator + item.NationalID + commaSeparator + 
                   item.SubSystemID + commaSeparator + item.System);
}

Then I've realized that there is much efficient way, by using string.Join

This does not work of course:

string joined = string.Join(",", listOfPersons);

And if I go by selecting property like this:

string joined = string.Join(",", listOfPersons(x => x.Id);

I get comma separated list only for that property of course.

Is there some more efficient way for getting each property separated by comma?

Upvotes: 5

Views: 9759

Answers (4)

Hussain
Hussain

Reputation: 449

Using Reflection where T : class

var valueLines =reportData.Select(row => string.Join(",", header.Split(',').Select(a => row.GetType().GetProperty(a).GetValue(row, null))));

eg

private MemoryStream GenerateExcelStream(List<T> reportData)
    {
        var lines = new List<string>();
        var header = "";
        var attFilter = new NoDisplayInReportAttribute();
        PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
        foreach (PropertyDescriptor prop in properties)
            if (!prop.Attributes.Matches(attFilter))
                header += prop.Name + ",";
        header = header.Substring(0, header.Length - 1);
        lines.Add(header);
        var valueLines =reportData.Select(row => string.Join(",", header.Split(',').Select(a => row.GetType().GetProperty(a).GetValue(row, null))));
        lines.AddRange(valueLines);
        MemoryStream memoryStream = new MemoryStream();
        TextWriter tw = new StreamWriter(memoryStream);
        lines.ForEach(x => tw.WriteLine(x));
        tw.Flush();
        return memoryStream;
    }

Upvotes: 0

Tim Schmelter
Tim Schmelter

Reputation: 460148

I would avoid reflection if possible.

You can achieve it with compile time safety and readable code easily:

IEnumerable<string> personTexts = listOfPersons
    .Select(p => String.Join(",", p.ReferenceNumber, p.FirstName, p.Surname, ...));
string joined = String.Join(Environment.NewLine, personTexts);

You have full control over which property should be used and in which order.

Upvotes: 19

fubo
fubo

Reputation: 45947

Overrride the ToString-Method for your Person-Class

public class Person
{
    //properties...

    public override string ToString()
    {
        return string.Join(",",
            this.ReferenceNumber,
            this.FirstName,
            this.Surname,
            this.MiddleName,
            this.Address1,
            this.Address2,
            this.Address3,
            this.Address4,
            this.City,
            this.PostalCode,
            this.Country,
            this.DateOfBirth.ToString(),
            this.ID,
            this.Gender,
            this.Component,
            this.NationalID,
            this.SubSystemID,
            this.System);
    }
}

so you can use Person.ToString() for csv-generation. Unlike the reflection approach you can easy

  • maintain the order
  • handle each type different (BirthDate.ToString("d"), Price.ToString("F2"))
  • skip values you don't need e.g. System.Collections.Generic.List1[System.String]
  • change values to your requirements (HasChildren ? "Yes" : "No")

Upvotes: 4

pwas
pwas

Reputation: 3373

Reflection is (sometimes) your friend:

var props = item.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance); // todo: cache & filter not-needed props)

var itemStr = string.Join(", ", 
                     props.Select(p => p.GetValue(item, null)?.ToString())
                          .ToArray());

Upvotes: 7

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