根据来自另一个gridview的检查值过滤gridview

I have two GridView. First is called "gvImage" which is the category gridview with checkbox for selection. Second GridView is called "GridView1", the Second GridView populates basing on the value selected in the First GridView, here I am able to populate the record in Second GridView only for one category checked (selected) from the First GridView, but when I check (select) multiple category from the First GridView(gvImage) then it is not populating the multiple category record in the Second GridView(GridView1). Please help me to get this, below is my Code behind:I have two GridView. First is called "gvImage"