Enable Views to expose "Design Time" default data?

[tznind]

By default, many Views have no good visual representation unless set with "data". E.g. ListView, RadioGroup, and Slider.

This Issue is to come up with a design and implementation that allows a "designer" (TGD) or "tester" (AllViewsTester/Unit Tests) component to say to a View "Hey, go into a good demo mode".

My current (probably lame) thinking is we'd do this by defining an interface that a View that supports such a thing could implement:

public interface ISupportsDesignMode
{
   // Call this to tell the View to load "demo data" 
   public bool LoadDemoData ();
}

 

Background

Slider<> is doing strange things when setting it's Text property.

    [Test]
    public void TestTextSliderString()
    {
        var s = new Slider<string>();
        ClassicAssert.IsEmpty(s.Options);

        var s2 = new Slider<string>();
        s2.Text = "I've got a lovely bunch of coconuts";
        ClassicAssert.IsEmpty(s2.Options);
    }

Text should be completely independent from Options.

It seems Text setter is putting data into Options. This is problematic for many reasons. It happens also with the <int> generic. Notice how if you reverse the properties it will have different result.

• Set Text first and you can overwrite with Options
• Set Options first and Text overwrites completely the Options

    [Test]
    public void TestTextSliderInt()
    {
        var o = new SliderOption<int>("hi", new System.Text.Rune('d'), 32);
        var s1 = new Slider<int>
        {
            Text = "fff",
            Options = new List<SliderOption<int>> { o }
        };

        Assert.That(s1.Options.Single(), Is.EqualTo(o));

        var s2 = new Slider<int>
        {
            // When order is reversed
            Options = new List<SliderOption<int>> {o },
            Text = "fff",
        };

        // It fails
        Assert.That(s2.Options.Single(),Is.EqualTo(o));
    }

[tig]

I wanted Slider to work in AllViewsTester so I made setting Text to a comma delimited string equivalent to setting Options.

Feel free to undo this, but I'd live ideas on how to make AllViewsTester support causing Views to be "useful/visible" without having custom logic per-view.

I did the same thing to RadioGroup.

[tznind]

Hmn, I don't think Text should be the place for this. It looks like a string but it behaves like a method.

In general I think properties are not the place for non deterministic behaviours.

Consider the following example:

    [Test]
    public void TestTextSliderString()
    {
        var s1 = new Slider<string>();
        var s2 = new Slider<string>();
        s2.Text = "I've got a lovely bunch of coconuts, here they are sitting in a row!";
     
        // This line does not do what it looks like
        s1.Text = s2.Text;

        TestContext.Out.WriteLine("Options:" + s1.Options.Count); //2
        TestContext.Out.WriteLine("Options:" + s2.Options.Count); //6!

        ClassicAssert.IsTrue(s1.Options.Count == s2.Options.Count );
    }

[BDisp]

I think the Text and Title properties should be independent and have no relationship between them. By default, Text will be drawn inside the view, with the exception of custom drawing. The Title should only be used when a view has a border and is not an empty string.

Edit:
This exposition is just to warn you that in this case Options and Text should not have any relationship between them, with the exception that Text can be used to reflect the string that will be displayed relative to the currently selected Options.