C# – Column headers in CSV using fileHelpers library

ccsvfilehelpers

Is there a built-in field attribute in the FileHelper library which will add a header row in the final generated CSV?

I have Googled and didn't find much info on it. Currently I have this:

DelimitedFileEngine _engine = new DelimitedFileEngine(T);
_engine.WriteStream
        (HttpContext.Current.Response.Output, dataSource, int.MaxValue);

It works, but without a header.

I'm thinking of having an attribute like FieldTitleAttribute and using this as a column header.

So, my question is at which point do I check the attribute and insert header columns? Has anyone done something similar before?

I would like to get the headers inserted and use custom text different from the actual field name just by having an attribute on each member of the object:

[FieldTitleAttribute("Custom Title")]
private string Name

and maybe an option to tell the engine to insert the header when it's generated.

So when WriteStream or WriteString is called, the header row will be inserted with custom titles.

I have found a couple of Events for DelimitedFileEngine, but not what's the best way to detect if the current record is the first row and how to insert a row before this.

Best Answer

I know this is an old question, but here is an answer that works for v2.9.9

FileHelperEngine<Person> engine = new FileHelperEngine<Person>();
engine.HeaderText = engine.GetFileHeader();

Related Solutions

C# – Should ‘using’ directives be inside or outside the namespace

There is actually a (subtle) difference between the two. Imagine you have the following code in File1.cs:

// File1.cs
using System;
namespace Outer.Inner
{
    class Foo
    {
        static void Bar()
        {
            double d = Math.PI;
        }
    }
}

Now imagine that someone adds another file (File2.cs) to the project that looks like this:

// File2.cs
namespace Outer
{
    class Math
    {
    }
}

The compiler searches Outer before looking at those using directives outside the namespace, so it finds Outer.Math instead of System.Math. Unfortunately (or perhaps fortunately?), Outer.Math has no PI member, so File1 is now broken.

This changes if you put the using inside your namespace declaration, as follows:

// File1b.cs
namespace Outer.Inner
{
    using System;
    class Foo
    {
        static void Bar()
        {
            double d = Math.PI;
        }
    }
}

Now the compiler searches System before searching Outer, finds System.Math, and all is well.

Some would argue that Math might be a bad name for a user-defined class, since there's already one in System; the point here is just that there is a difference, and it affects the maintainability of your code.

It's also interesting to note what happens if Foo is in namespace Outer, rather than Outer.Inner. In that case, adding Outer.Math in File2 breaks File1 regardless of where the using goes. This implies that the compiler searches the innermost enclosing namespace before it looks at any using directive.

Mysql – How to output MySQL query results in CSV format

From Save MySQL query results into a text or CSV file:

SELECT order_id,product_name,qty
FROM orders
WHERE foo = 'bar'
INTO OUTFILE '/var/lib/mysql-files/orders.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n';

Note: That syntax may need to be reordered to

SELECT order_id,product_name,qty
INTO OUTFILE '/var/lib/mysql-files/orders.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n'
FROM orders
WHERE foo = 'bar';

in more recent versions of MySQL.

Using this command, columns names will not be exported.

Also note that /var/lib/mysql-files/orders.csv will be on the server that is running MySQL. The user that the MySQL process is running under must have permissions to write to the directory chosen, or the command will fail.

If you want to write output to your local machine from a remote server (especially a hosted or virtualize machine such as Heroku or Amazon RDS), this solution is not suitable.

Best Answer

Related Solutions

C# – Should ‘using’ directives be inside or outside the namespace

Mysql – How to output MySQL query results in CSV format

Related Topic