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POAdvice on setting up new TreeView Data Type
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copied!<p>I would like some advice and or tips on how to go about setting up a new Object Class for a TreeView using the TreeView's Node.Data property.</p> <p>I know how to create a basic Object type that can write/read from the .Data property, I do something like this:</p> <pre><code>type TMyData = class(TComponent) private FString1: String; FString2: String; FInteger1: Integer; published property String1: String read FString1 write FString1; property String2: String read FString2 write FString2; property Integer1: Integer read FInteger1 write FInteger1; end; </code></pre> <p><strong>To write a value to one of the properties Node.Data property:</strong></p> <pre><code>TMyData(TreeView1.Selected.Data).String1:= 'save this String'; </code></pre> <p><strong>To read a value:</strong></p> <pre><code>ShowMessage(TMyData(TreeView1.Selected.Data).String1); </code></pre> <p>Thats a pretty basic example of assigning Data to a Tree Node, Now this is where I need the help and advice, tips etc...</p> <p>From my example above, you can easily read/write standard properties such as String, Integer, Boolean etc. What about including and reading/writing to and from say a TListBox or TListView?</p> <p>Instead of writing standard data to a Tree Node, how about adding items to that TListView and writing the contents of that TListView to the TreeView Node.</p> <p>What if when clicking on one of the Tree Nodes, instead of returning a string, it could populate that TListView with Items and Images that were saved to earlier.</p> <p><strong>(1)</strong> This is the main form where you can add the Nodes to the TreeView. I actually use a more enhanced function to add to my TreeView, like so:</p> <pre><code>function AddMyDataNode(ATreeView: TTreeView; NodeName: String; NodeImage: Integer; String1, String2: String; Integer1: Integer; SelectNode: Boolean): TTreeNode; var Obj: TMyData; Node: TTreeNode; begin Result:= nil; Obj:= TMyData.Create(nil); try Obj.String1:= String1; Obj.String2:= String2; Obj.Integer1:= Integer1; Node:= ATreeView.Items.AddObject(ATreeView.Selected, NodeName, Obj); Node.ImageIndex:= NodeImage; Node.SelectedIndex:= NodeImage; Result:= Node; if SelectNode then Node.Selected:= True; ATreeView.SetFocus; except on E: Exception do ShowMessage('Could not add MyData Node: ' + E.Message); end; end; </code></pre> <p>Editing a Node will show another form called the Data Form...:</p> <p><strong>(2)</strong> This Data Form is where the data from the Node on the Main Form is read/written. With an addition of a TListView. The ListView should also be read/saved with the standard properties too.</p> <p>Adding/Editing a ListView item may include other standard properties, such as:</p> <p><strong>(3)</strong> The values on this form are saved into the ListView data.</p> <p>So in a nutshell:</p> <ul> <li>The TreeView Node.Data stores standard properties and also a TListView.</li> <li>This Data is show on another form called Data Form.</li> <li>The ListView on the Data Form also has data.</li> <li>Editing the ListView on the Data Form will show an additional Form with standard properties.</li> </ul> <p>I would like to know how I could best approach this, what tips could you provide, what is the easiest way to achieve something like this etc?</p> <p>Writing/Reading to and from the ListView is easily implemented I imagine in that it can be done by accessing the <code>ListView Items.Item[x].Data</code> property. Getting the ListView Data to store with the TreeView is the problem, I don't know how I could implement this type of behaviour.</p> <p>I would like to know advice on things like how I could define the Types etc.</p> <p>I look forward to hearing your ideas on this.</p>

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