How to use WebCurrencyEdit in a WebGrid?

How do I use the WebCurrencyEdit control in a WebGrid??

I am following the documentation exactly(Please look at code snippet) but when I try to build this, it gives me a "Null Reference Exception" at the last line.

May be I am exhausted so cant think right. It must be simple. Please help

Below is what I got from documentation:
You can use a custom editor control as an editor in the WebGrid". In order to serve as a custom editor control, the control you use must implement the IProvidesEmbeddableEditor interface.

Follow These Steps:
Add a WebGrid to a web form (if it does not already exist) and set up any data binding and column structure for the grid.
Allow users to edit the grid data by setting the AllowUpdateDefault property to true for the control. You can optionally leave the control as read-only and set just the column(s) that will contain the custom control(s) to be editable.
Place the control that will serve as the custom editor onto the web form at design-time, or create it through code in the code-behind for the web form. You must use a control that is capable of being used as a custom editor (implements the IProvidesEmbeddableEditor interface.)
Change the Type property of the column that will contain the custom editor to "Custom".
Set the EditorControlID property of the column to the ID of the custom editor control. If you have placed the custom editor control on the web form at design-time, you can select the name of the control from the dropdown that appears when editing the EditorControlID property in the Visual Studio property sheet. This dropdown shows all controls on the web form capable of being used as custom editors.
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Infragistics.WebUI.WebDataInput.WebCurrencyEdit ctrlCurrEdit = new Infragistics.WebUI.WebDataInput.WebCurrencyEdit();
ctrlCurrEdit.ID = "ctrlCE";
myGrid.Columns[1].Type = ColumnType.Custom;
myGrid.Columns[1].EditorControlID =  "ctrlCE";