Cannot add aspxgridview column using devexpress in server side of VB.NET

Hi all,
i am trying to add one ASPXGridView Column using DevExpress in server side of vb.net .
the column i have added successfully but i cannot add DataItemTemplate.
if am trying to add below code then i am getting below error,
So please drop me any solution.
Error:
 
Unable to cast object of type 'System.String' to type 'System.Web.UI.ITemplate'
 
My code is :

     colText = New DevExpress.Web.ASPxGridView.GridViewDataTextColumn
                colText.FieldName = "Image"
                colText.Caption = "Image"
                colText.VisibleIndex = "16"
                colText.DataItemTemplate = "<a href='javascript:void(0);' onclick='OnMoreInfoClick(this, '<%# Container.KeyValue %>')'>ShowImage</a>"  // here am getting above error
                colText.CellStyle.HorizontalAlign = HorizontalAlign.Right
                colText.CellStyle.Border.BorderColor = Drawing.Color.DarkBlue
                colText.CellStyle.Border.BorderStyle = BorderStyle.Double
                colText.EditFormCaptionStyle.HorizontalAlign = HorizontalAlign.Right
                colText.CellStyle.VerticalAlign = VerticalAlign.Middle
                colText.CellStyle.HorizontalAlign = HorizontalAlign.Right
 
                If Page.IsPostBack = False Then
                    Grid.Columns.Add(colText)
                End If

thanks in advance