Rendering an unordered list using asp.net

Question

I need to render a unordered list with the data obtained from database using asp.net/C#.My data looks something like this.

id     Name               Depth

1    ELECTRONICS             0

2    TELEVISIONS             1

3    Tube                   2

4    LCD                    2

5    Plasma                 2

6   Portable electronics    1

7   MP3 Player              2

8    Flash                  3

9    CD Players             2

10    2 Way Radio           2

using the above sample data I need to render an unordered list based on the depth, in the following format

<ul>
  <li>ELECTRONICS

<ul>

   <li>TELEVISIONS

  <ul>

    <li>TUBE</li>

    <li>LCD</li>

    <li>PLASMA</li>

  </ul>

   </li>

   <li>PORTABLE ELECTRONICS
  <ul>

    <li>MP3 PLAYERS

   <ul>

<li>FLASH</li>

   </ul>

    </li>

    <li>CD PLAYERS</li>

    <li>2 WAY RADIOS</li>

  </ul>

   </li>

</ul>

</li>

</ul>

Above data is just a sample,I have a huge recordset which has to be converted to unordered list.Could someone please give me an idea on how to achieve this?

UPDATE: I've updated my code which generates unordered list to the following .

int lastDepth = -1;
        int numUL = 0;

        StringBuilder output = new StringBuilder();


        foreach (DataRow row in ds.Tables[0].Rows)
        {

            int currentDepth = Convert.ToInt32(row["Depth"]);

            if (lastDepth < currentDepth)
            {
                if (currentDepth == 0)
                {
                    output.Append("<ul class=\"simpleTree\">");
                    output.AppendFormat("<li class=\"root\"><span><a href=\"#\" title=\"root\">root</a></span><ul><li class=\"open\" ><span><a href=\"#\" title={1}>{0}</a></span>", row["name"],row["id"]);
                }
                else
                {
                    output.Append("<ul>");
                    if(currentDepth==1)
                    output.AppendFormat("<li><span>{0}</span>", row["name"]);
                    else
                        output.AppendFormat("<li><span class=\"text\"><a href=\"#\" title={1}>{0}</a></span>", row["name"], row["id"]);
                }
                numUL++;
            }
            else if (lastDepth > currentDepth)
            {
                output.Append("</li></ul></li>");
                if(currentDepth==1)
                output.AppendFormat("<li><span>{0}</span>", row["name"]);
                else
                    output.AppendFormat("<li><span class=\"text\"><a href=\"#\" title={1}>{0}</a></span>", row["name"], row["id"]);
                numUL--;
            }
            else if (lastDepth > -1)
            {
                output.Append("</li>");
                output.AppendFormat("<li><span class=\"text\"><a href=\"#\" title={1}>{0}</a></span>", row["name"],row["id"]);
            }


            lastDepth = currentDepth;
        }

        for (int i = 1; i <= numUL+1; i++)
        {
            output.Append("</li></ul>");
        }

With the above code my unordered list looks like this.

<ul class="simpleTree">
<li class="root">
<span><a href="#" title="root">root</a></span>
<ul>
<li class="open" >
<span><a href="#" title=1>ELECTRONICS</a></span>
<ul>
<li>
<span>TELEVISIONS</span>
<ul>
<li>
<span class="text"><a href="#" title=3>TUBE</a></span>
</li>
<li>
<span class="text"><a href="#" title=4>LCD</a></span>
</li>
<li><span class="text"><a href="#" title=5>PLASMA</a></span>
</li>
</ul>
</li>
<li>
<span>PORTABLE ELECTRONICS</span>
<ul>
<li>
<span class="text"><a href="#" title=7>MP3 PLAYERS</a></span>
<ul>
<li>
<span class="text"><a href="#" title=8>FLASH</a></span>
</li>
</ul>
</li>
<li>
<span class="text"><a href="#" title=9>CD PLAYERS</a></span>
</li>
<li>
<span class="text"><a href="#" title=10>2 WAY RADIOS</a></span>
</li>
</ul>
</li></ul>
</li></ul>
</li></ul>

Thanks.

Answer 1

You could do something like this in code and then output the result to a Literal control on your page:

int lastDepth = -1;
int numUL = 0;

StringBuilder output = new StringBuilder();


foreach (DataRow row in yourDataTable.Rows) {

    int currentDepth = row["Depth"];

    if (lastDepth < currentDepth) {
        output.append("<ul>");
        numUL++
    }
    else if (lastDepth > currentDepth) {
        output.append("</li></ul></li>");
        numUL--
    }
    else if (lastDepth > -1) {
        output.append("</li>");
    }

    output.appendformat("<li class=\"depth-{1}\">{0}", row["name"], currentDepth);

    lastDepth = currentDepth;
}

for (int i = 1;i <= numUL;i++)
{
    output.append("</li></ul>");
}



yourLiteralControl.Text = output.toString();

Update: I made it so that it will put in a css class on the list items related to the depth as requested in the comments.

Answer 2

Use the Repeater Control.

Samples:

• Sample 1
• Sample 2

MSDN Documentation

Edit: Didn't notice the part about depth, use the Treeview Control instead, look at the part about binding to a database.

Answer 3

Unless you're using .NET 2.0 you should use the ListView Control.

Using ASP.NET 3.5's ListView and DataPager Controls: Displaying Data with the ListView