Create ‘Open Tool Pane’ link in custom .NET Web Parts for SharePoint 2010

Back in SharePoint 2007, it was pretty popular to use the built-in Javascript function MSOTlPn_ShowToolPane2Wrapper to put the Web part page into edit mode and have the Web part properties editable. Typically, you would put something like the following in your Web part class code:

protected override void OnPreRender(EventArgs e)
{
if (this.Page != null)
{
if (string.IsNullOrEmpty(SelectedListName))
{
placeHolderLiteral.Text = "
Web part is not configured. Please <a href="\&quot;javascript:MSOTlPn_ShowToolPane2Wrapper('Edit',">edit the Web part</a> and choose a list or library.

";
}
}
}

In the example above, I render a “please configure the Web part” message whenever the SelectedListName of the Web part is not set.

I’m currently developing a Web part for SharePoint 2010 and I wanted to have a “configure” link displayed for the Web part whenever Web properties (i.e. list name, view ID etc.) are not set or specified . I embed a code similar to the above snippet where I use MSOTlPn_ShowToolPane2Wrapper. It didn’t work!

So, thinking like a developer, I observe how the out-of-the-box Web parts render an “open tool pane” hyperlink. I add an Image Viewer web part to a web part page and look at the structure of the hyperlink. Here’s what I saw:

I replaced my output code in my web part class from MSOTlPn_ShowToolPane2Wrapper to ShowToolPane2Wrapper and it works!
Please note that I encourage that you put ‘this’ (object) as the second argument instead of ‘129’, or ’16’ as you see in some blogs out there. The second parameter is supposed to indicate which Web part to edit. Do you really know at run-time that your Web part is ‘129’ or ’16’? You don’t! So simply use ‘this’.