Accessing a Button in a Visual WebGui ListView

Mark Berry December 3, 2010

I’ve developed a Visual WebGui 6.4 RC1 form that uses a ListView control with a button in each row. The button opens a custom control when pressed. It’s very similar to the “Custom ListView with control” demo in the CompanionKit.

At one point I need to be able to change the text of the button from “outside” the ListView, i.e. with no reference to the button. It took me a while to figure out how to get to the control. Here’s what I found.

When you create a ListView row, you first add a ListViewItem, then, using a reference to that ListViewItem, you add SubItems one by one. In my case, the fifth column contains the button and was created as follows:

// Edit button
Gizmox.WebGUI.Forms.Button objButton = new Gizmox.WebGUI.Forms.Button();
objButton.Click += new EventHandler(OnEditButtonClick);
objButton.Tag = objListViewItem;
objButton.Text = "Edit";
objListViewItem.SubItems.Add(objButton);

Here is the code that finally gave me access to the button control:

// Need to change button text to "Edit"
// Can't directly convert Subitem to Control, so convert to Object first
Object objSubItem = 
    this.listView1.Items[mintListViewSavedIndex].SubItems[4];
ListViewItem.ListViewSubControlItem objControl = 
    objSubItem as ListViewItem.ListViewSubControlItem;
if (objControl != null)
{
    objControl.Text = "Edit";
}

The non-obvious part was to figure out the “ListViewItem.ListViewSubControlItem” type so I could gain access to its properties (like .Text). I realized I could use .GetType() to find out what kind of object it is.

VWG control subitem

This returned Gizmox.WebGUI.Forms.ListViewItem+ListViewSubControlItem. The +ListViewSubControlItem indicates that it is a nested class under ListViewItem. Replacing the plus sign with a period, I was able to access the control as ListViewItem.ListViewSubControlItem.


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