Question

I have a custom class that I use to build table strings. I would like to rewrite the code so that I can chain the operators. Something like:

myObject
  .addTableCellwithCheckbox("chkIsStudent", isUnchecked, isWithoutLabel)
  .addTableCellwithTextbox("tbStudentName", isEditable) etc.

So it seems like I would have each of these methods(functions) return the object itself so that I can then call another method(function) on the resulting object, but I can’t figure out how to get a c# class to refer to itself.

Any help?

Answer 1

So you would create a fluent interface like this:

class FluentTable 
{
  //as a dumb example I'm using a list
  //use whatever structure you need to store your items
  List<string> myTables = new List<string>();

  public FluentTable addTableCellwithCheckbox(string chk, bool isUnchecked, 
                                                        bool  isWithoutLabel)
  {
    this.myTables.Add(chk);
    //store other properties somewhere
    return this;
  }

  public FluentTable addTableCellwithTextbox(string name, bool isEditable)
  {
    this.myTables.Add(name);
    //store other properties somewhere
    return this;
  }
  public static FluentTable New()
  {
    return new FluentTable();
  }
}

Now you could use it like this:

  FluentTable tbl = FluentTable
                    .New()
                    .addTableCellwithCheckbox("chkIsStudent", true, false)
                    .addTableCellwithTextbox("tbStudentName", false);

This should give you a basic idea of how you need to go about it. See fluent interfaces on wikipedia.

A more correct way to do it would be to implement a fluent interface:

interface IFluentTable
{
 IFluentTable addTableCellwithCheckbox(string chk, bool isUnchecked, 
                                                        bool  isWithoutLabel)
 IFluentTable addTableCellwithTextbox(string name, bool isEditable)
 //maybe you could add the static factory method New() here also 
}

And then implement it : class FluentTable : IFluentTable {}