I am trying to build a TreeView WebControl. I have started out by building a

flat list of 'LiteralControls' for each of the node objects. I quickly

realized that I will need to insert lists into the hierarchy so a

one-dimensional array will not do. In other words I cannot use just the

Controls array I need utilize the Controls member of each control to insert

child controls in order to build this hierarchy. I will have something like:



LiteralControl list;



list = new LiteralControl("<LI></LI>");



list.Controls.Add(new LiteralControl("<IMG></IMG>"));

list.Controls.Add(new LiteralControl("<A></A>");



sublist = new LiteralControl("<UL></UL>");

list.Controls.Add(sublist);



sublist.Controls.Add(new LiteralControl("<LI></LI>");

.

.

Controls.Add(list);

etc. . . .



The problem is that it seems that the child controls do not seem to get

renered. Looking at the documentation I notice that there is a protected

members "HasControls" and "ChildControlsCreated" and "EnsureChildControls"

and "RenderChildren". I have not set any of that up so am I right to assume

that if I want to have child controls I have to build my own class? In my

case this class would be something like TreeNode. Are there any examples or

hints as to how I would go about developing a user defined WebControl that

has custom controls in it?



Thank you.



Kevin Burton

kevin.burton@i...

I seemed to have found the answer to my problem. If I do the following the

hierarchy is preserved:



HtmlGenericControl list = new HtmlGenericControl("LI");



HtmlImage image = new HtmlImage();

image.Src = "images/dc.gif"

image.Width = 16;

list.Controls.Add(image);



HtmlAnchor anchor = new HtmlAnchor();

anchor.Title = "Title";

anchor.InnerText = "InnerText";

list.Controls.Add(anchor);



HtmlGenericControl sublist = new HtmlGenericControl("UL");

....

list.Controls.Add(sublist);



(etc.) . . .



This is very helpful because now I can build a hierarchy of controls. Now I

need to be able to respond to the ServerClick event. I want to be able to

respond the a ServerClick event for HtmlImage but it does not seem to have

that as part of its member functions. Does anyone have some example code

where I can respond to a click event on the server? How would I add this to

the HtmlImage control? The effect I want is to change the image when it is

clicked on simulating an expanded or collapsed list (like a TreeView

control). If you can see a better ay to do this I would appreciate any

suggestions.



Thank you.



Kevin Burton

kevin.burton@i...





-----Original Message-----

From: kevin.burton@i... [mailto:kevin.burton@i...]

Sent: Wednesday, December 06, 2000 11:40 AM

To: ASP+

Subject: [aspx] Building a hierarchy or controls.





I am trying to build a TreeView WebControl. I have started out by building a

flat list of 'LiteralControls' for each of the node objects. I quickly

realized that I will need to insert lists into the hierarchy so a

one-dimensional array will not do. In other words I cannot use just the

Controls array I need utilize the Controls member of each control to insert

child controls in order to build this hierarchy. I will have something like:



LiteralControl list;



list = new LiteralControl("<LI></LI>");



list.Controls.Add(new LiteralControl("<IMG></IMG>"));

list.Controls.Add(new LiteralControl("<A></A>");



sublist = new LiteralControl("<UL></UL>");

list.Controls.Add(sublist);



sublist.Controls.Add(new LiteralControl("<LI></LI>");

.

.

Controls.Add(list);

etc. . . .



The problem is that it seems that the child controls do not seem to get

renered. Looking at the documentation I notice that there is a protected

members "HasControls" and "ChildControlsCreated" and "EnsureChildControls"

and "RenderChildren". I have not set any of that up so am I right to assume

that if I want to have child controls I have to build my own class? In my

case this class would be something like TreeNode. Are there any examples or

hints as to how I would go about developing a user defined WebControl that

has custom controls in it?



Thank you.



Kevin Burton

kevin.burton@i...







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