Stop using Str

In magic, converting numbers dates etc... to string - was unnecessaraly complicated, and as such the migrated code will reflect that.

In this article we'll take a piece of migrated code and demo better ways of writing it including C# 6 style string and more.

Let's review the following code where we define 4 columns, put values in them and display a Message Box.

TextColumn FirstName = new TextColumn("First Name", "20");
TextColumn LastName = new TextColumn("Last Name", "20");
DateColumn BirthDate = new DateColumn("Birth Date", "DD/MM/YYYY");
NumberColumn Age = new NumberColumn("Age", "3");
FirstName.Value = "Noam";
LastName.Value = "Honig";
BirthDate.Value = new Date(1976, 6, 16);
Age.Value = 42;


Message.ShowWarning(
	"Name:" + u.Trim(FirstName) + " " + u.Trim(LastName) + //it's so long that I've put it in two lines
    " Born On " + u.DStr(BirthDate, "DD/MM/YYYY") + " Age " + u.Trim(u.Str(Age, "3")));

The result is: Name:Noam Honig Born On 16/06/1976 Age 42

Let's try to focus on the string build in line 12 and 13 and improve on it.

Step 1 - Replace u.Str and u.Dstr methods with ToString

The ToString method is used to convert any object to string, and is what any .NET developer would use, let's do that.

- u.DStr(BirthDate, "DD/MM/YYYY")
  BirthDate.ToString("DD/MM/YYYY")
- u.Str(Age, "3")
  Age.ToString("3") 
"Name:" + u.Trim(FirstName) + " " + u.Trim(LastName) + //it's so long that I've put it in two lines
    " Born On " + BirthDate.ToString("DD/MM/YYYY") + " Age " + u.Trim(Age.ToString("3")));

Step 2 - Remove the Format

In magic you had to specify the Picture to the Str method. In .NET if you don't specify a Format the Format that was defined in the column is used.

  • This also has the benefit that if we change the Format in the Column (or the type) it'll affect all the string conversions
- BirthDate.ToString("DD/MM/YYYY")
  BirthDate.ToString()
- Age.ToString("3")
  Age.ToString() 
"Name:" + u.Trim(FirstName) + " " + u.Trim(LastName) + //it's so long that I've put it in two lines
    " Born On " + BirthDate.ToString() + " Age " + u.Trim(Age.ToString()));

Some developers in magic tried to solve the problem of redefining the picture in the STR method by calling the varpic command Str(A,VarPic(A,0)) a nice try to solve a problem that shouldn't have been there to begin with :)

Step 3 - Remove the ToString

In .NET when the + operator is used between a string and anything - the ToString method is called automatically. This helps us with the Birth Date Column.

- " Born On " + BirthDate.ToString() + " Age "
  " Born On " + BirthDate + " Age " 
"Name:" + u.Trim(FirstName) + " " + u.Trim(LastName) + //it's so long that I've put it in two lines
    " Born On " + BirthDate + " Age " + u.Trim(Age.ToString()));

Moving complex formatting logic to the Type

You can also move all your formatting logic to the "Type" class, and have a it all in one place. That way you can create complex formatting rules once and reuse them.

So Instead of writing something like this:

"Quantity : " + v_Qty.ToString(v_Qty % 1 == 0 ? "10" : "10.5").Trim();

You'll be able to write:

"Quantity : " + v_Qty;

Just add the ToString method to your Quantity type class

public class Quantity:NumberColumn
{
    public Quantity():base("Quantity","10.5")
    {
    }
    public override string ToString()
    {
         return this.ToString(this % 1 == 0 ? "10" : "10.5").Trim();
    }
}

So far so good

If you got this far - you've got most of the benefits.

If you want to push it further, continue to explore the new features of C#6 and see how they can improve the way you work

Step 4 - Use C#6 Style string

In C#6 a new way of building strings was introduced. Simply add the $ sign before the open quotes, and now you can include members within curley brakets in your string.

- "Name:" + u.Trim(FirstName) + " " + u.Trim(LastName) + " Born On"
  $"Name:{u.Trim(FirstName)} {u.Trim(LastName)} Born On" 
$"Name:{u.Trim(FirstName)} {u.Trim(LastName)} Born On {BirthDate} Age {u.Trim(Age.ToString())}"

The code between the Curley brakets is regular C# code, so you have intelisense and visual studio will keep you safe when you build.

Formatting - you can also apply formatting to C#6 style string

Simply put the format after : sign.

For example:

- "Age " + u.Str(Age, "3P0")+ ".";
  $"Age {Age:3P0}.";

Result will be: Age 42.

The support for migrated style format in C#6 style was added on December 2018 - you can easily add it to source code of older migrations by following this article Add Support for CSharp 6 String Manipulation Format to Older Code

Step 5 - Remove the Trim

I HATE TRIM!!!!

In magic any Alpha had trailing spaces to it - so any migrated code behaves like that.

This means that if I try to create a full name by writing FirstName + LastName + ":" I'll get:

Noam                Honig              :
    ^^^^^^^^^^^^^^^^     ^^^^^^^^^^^^^^ //the spaces we hate

To solve that we've added a new format special character ~ that whenever it's added to a format, it'll make sure it's trimmed.

- $"Name:{u.Trim(FirstName)} {u.Trim(LastName)} Born On {BirthDate} Age {u.Trim(Age.ToString())}"
  $"Name:{FirstName:~} {LastName:~} Born On {BirthDate} Age {Age:~}"

The support for ~ sign as trim in formats was added on December 2018 - you can easily add its source code of older migrations by following this article Add Support for Telde Format Char to Trim

The End Result Comparison

  $"Name:{FirstName:~} {LastName:~} Born On {BirthDate} Age {Age:~}"
- "Name:" + u.Trim(FirstName) + " " + u.Trim(LastName) + " Born On " + BirthDate + " Age " + u.Trim(Age.ToString()));

This code is a lot easier to read and is a almost 50% shorter.

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or email us at info@fireflymigration.com