在gridview中选中复选框，在c＃codebehind checked属性中为false

I have custom upload control. The control has gridview with the uploaded documents and the first column has checkbox for selecting documents I want to delete by clicking Delete button. The upload control is contained in other UserControls almost everywhere in the application and works properly, except at one control. The problem is when I check some document for deleting, when the code executes the checked property of the checkbox is false.I have custom upload control. The control has g