TJvInspector - Get Property Values?

Question

How do you get the value that has been entered into the JvInspector at runtime?

The Demo in \..\jvcl\examples\JvInspector shows how to add strings, by writing something like this (extract from the demo):

var
  FirstName: string;

implementation

procedure TfrmInspector.AddVarious;
var
  InspCat: TJvInspectorCustomCategoryItem;
begin
  TJvInspectorVarData.New(InspCat, 'First', TypeInfo(string), @FirstName).DisplayName := 'Copy of first name';
end;

I wanted to add a TColor property so I did this:

var
  FirstName: string;
  SomeColor: TColor;

implementation

procedure TfrmInspector.AddVarious;
var
  InspCat: TJvInspectorCustomCategoryItem;
begin
  TJvInspectorVarData.New(InspCat, 'First', TypeInfo(string), @FirstName).DisplayName := 'Copy of first name';
  TJvInspectorVarData.New(InspCat, 'SomeColor', TypeInfo(TColor), @SomeColor;
end;

This displays correctly but I cannot seem to get the value that is changed for SomeColor when selecting a new color from the dropdown list in the inspector.

I tried this:

procedure TfrmInspector.JvInspector1ItemValueChanged(Sender: TObject;
  Item: TJvCustomInspectorItem);
begin
  if (Item.Data <> nil) and (CompareText(Item.Data.Name, 'FirstName') = 0) then
    ShowMessage(Item.Data.AsString) //< works
  else if (Item.Data <> nil) and (CompareText(Item.Data.Name, 'SomeColor') = 0) then
    ShowMessage(ColorToString(TColor(Item.Data))); //< does not return correct value
end;

I don't normally use Jedi components but thought I would give them another chance but there seems to be little documentation, I looked on the Wiki page for OnItemValueChanged event: http://wiki.delphi-jedi.org/wiki/JVCL_Help:TJvInspector.OnItemValueChanged but again barely any information or help.

I am sure instead of trying to get ColorToString(TColor(Item.Data)) I need to use Item.Data.AsVariant but I could be wrong, when I tried I got AV errors so I probably am totally wrong, nothing I ever do or try seems to work :(

Answer 1

The Item.Data property is an object reference of type TJvCustomInspectorData; type-casting it to TColor yields nonsense. TColor is an ordinal type, so use the AsOrdinal method just as the string code uses AsString:

ShowMessage(ColorToString(TColor(Item.Data.AsOrdinal)));

Alternatively, you should just be able to read from the global SomeColor variable you passed when you created the item in the first place.

Answer 2

I found one way that works:

procedure TfrmInspector.JvInspector1ItemValueChanged(Sender: TObject;
  Item: TJvCustomInspectorItem);
var
  sVal: string;
begin
  if (Item.Data <> nil) then
  begin
    sVal := Item.DisplayValue;

    if (CompareText(Item.Data.Name, 'FirstName') = 0) then
      ShowMessage('FirstName Value: ' + sVal)
    else if (CompareText(Item.Data.Name, 'SomeColor') = 0) then
      ShowMessage('SomeColor Value: ' + sVal); //<can use StringToColor now
  end;
end;

Though probably not the best way I thought I would post it anyway.