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How to obtain a list of all published property names and types defined in a comp Turn on/off line numbers in source code. Switch to Orginial background IDE or DSP color Comment or reply to this aritlce/tip for discussion. Bookmark this article to my favorite article(s). Print this article
19-Oct-02
Category
Object Pascal
Language
Delphi 2.x
Views
94
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Publisher:
DSP, Administrator
Reference URL:
DKB
			Author: Jonas Bilinkevicius

How to obtain a list of all published property names and types defined in a 
component

Answer:

Solve 1:

1   function GetComponentProperties(Instance: TPersistent; AList: TStrings): 
2   Integer;
3   var
4     I, Count: Integer;
5     PropInfo: PPropInfo;
6     PropList: PPropList;
7   begin
8     Result := 0;
9     Count := GetTypeData(Instance.ClassInfo)^.PropCount;
10    if Count > 0 then
11    begin
12      GetMem(PropList, Count * SizeOf(Pointer));
13      try
14        GetPropInfos(Instance.ClassInfo, PropList);
15        for I := 0 to Count - 1 do
16        begin
17          PropInfo := PropList^[I];
18          if PropInfo = nil then
19            Break;
20          if IsStoredProp(Instance, PropInfo) then
21          begin
22            {
23            case PropInfo^.PropType^.Kind of
24              tkInteger:
25              tkMethod:
26              tkClass:
27              ...
28            end;
29            }
30          end;
31          Result := AList.Add(PropInfo^.Name);
32        end;
33      finally
34        FreeMem(PropList, Count * SizeOf(Pointer));
35      end;
36    end;
37  end;



Solve 2:

38  uses
39    TypInfo
40  
41  procedure ListProperties(AInstance: TPersistent; AList: TStrings);
42  var
43    i: integer;
44    pInfo: PTypeInfo;
45    pType: PTypeData;
46    propList: PPropList;
47    propCnt: integer;
48    tmpStr: string;
49  begin
50    pInfo := AInstance.ClassInfo;
51    if (pInfo = nil) or (pInfo^.Kind <> tkClass) then
52      raise Exception.Create('Invalid type information');
53    pType := GetTypeData(pInfo); {Pointer to TTypeData}
54    AList.Add('Class name: ' + pInfo^.Name);
55    {If any properties, add them to the list}
56    propCnt := pType^.PropCount;
57    if propCnt > 0 then
58    begin
59      AList.Add(EmptyStr);
60      tmpStr := IntToStr(propCnt) + ' Propert';
61      if propCnt > 1 then
62        tmpStr := tmpStr + 'ies'
63      else
64        tmpStr := tmpStr + 'y';
65      AList.Add(tmpStr);
66      FillChar(tmpStr[1], Length(tmpStr), '-');
67      AList.Add(tmpStr);
68      {Get memory for the property list}
69      GetMem(propList, sizeOf(PPropInfo) * propCnt);
70      try
71        {Fill in the property list}
72        GetPropInfos(pInfo, propList);
73        {Fill in info for each property}
74        for i := 0 to propCnt - 1 do
75          AList.Add(propList[i].Name + ': ' + propList[i].PropType^.Name);
76      finally
77        FreeMem(propList, sizeOf(PPropInfo) * propCnt);
78      end;
79    end;
80  end;
81  
82  function GetPropertyList(AControl: TPersistent; AProperty: string): PPropInfo;
83  var
84    i: integer;
85    props: PPropList;
86    typeData: PTypeData;
87  begin
88    Result := nil;
89    if (AControl = nil) or (AControl.ClassInfo = nil) then
90      Exit;
91    typeData := GetTypeData(AControl.ClassInfo);
92    if (typeData = nil) or (typeData^.PropCount = 0) then
93      Exit;
94    GetMem(props, typeData^.PropCount * SizeOf(Pointer));
95    try
96      GetPropInfos(AControl.ClassInfo, props);
97      for i := 0 to typeData^.PropCount - 1 do
98      begin
99        with Props^[i]^ do
100         if (Name = AProperty) then
101           result := Props^[i];
102     end;
103   finally
104     FreeMem(props);
105   end;
106 end;


And calling this code by:

ListProperties(TProject(treeview1.items[0].data), memo3.lines);

My tProject is defined as

107 type
108   TProject = class(tComponent)
109   private
110     FNaam: string;
111     procedure SetNaam(const Value: string);
112   public
113     constructor Create(AOwner: tComponent);
114     destructor Destroy;
115   published
116     property Naam: string read FNaam write SetNaam;
117   end;


Also note the output, there seem to be 2 standard properties (Name and Tag) !

Memo3
Class name: TProject

3 Properties
-------------------
Name: TComponentName
Tag: Integer
Naam: String

			
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