Image button not firing OnClick event

Hi
I am having 2 image suttons and textboxes in my asp.net page(vs 2005)

ShowwAll  and  Update

When i click AhowAll ,all the records will be displayed int the grid.

Grid is having one [Edit] field.

<asp:TemplateField HeaderText="Edit">

<ItemTemplate>

<asp:LinkButton Go to the complete details ...