Gridview giving the value of previous row

Question

I am binding data to a gridview. Then I am adding a row at the top of the gridview. As soon as I click any column(hyperlink), the gridview gives me the id of the previous row.

The aspx file

pyramid_jinja2

CS File

 <asp:GridView ID="gridview1" runat="server" 
                      OnRowCommand="OnRowCommand"  OnPreRender="OnPreRender" >
                     <Columns>
                         <asp:TemplateField>
                             <ItemTemplate>
                                 <asp:ImageButton ID="EditImage" src="image/clickme.png"/>
                             </ItemTemplate>
                         </asp:TemplateField>
                     </Columns>
                 </asp:GridView>

--Adding the First Row of textboxes and then Binding the image to the value of id (FIRST COLUMN VALUE)

--Binding data to the gridview

 protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {

            foreach (DataColumn col in dt.Columns)            
            {
                BoundField bfield = new BoundField();
                bfield.DataField = col.ColumnName;
                bfield.HeaderText = col.ColumnName;

                gridview1.Columns.Add(bfield);
            }
         }
    }

--Clicking on image and getting the value of previous row

  protected void OnPreRender(object sender, EventArgs e)
    {
            GridViewRow row = new GridViewRow(1, 1, DataControlRowType.Header, DataControlRowState.Normal);
            for (int i = 0; i < gridview1.Columns.Count; i++)
            {
                TableHeaderCell cell = new TableHeaderCell();
                TextBox txtSearch = new TextBox();
                txtSearch.Attributes["placeholder"] = gridview1.Columns[i].HeaderText;
                txtSearch.CssClass = "search_textbox";
                row.Controls.Add(cell);                
            }
            gridview1.Controls[0].Controls.AddAt(0, row);

           for (int i=0; i <gridview1.Rows.Count; i++)
            {
                GridViewRow row = gridview1.Rows[i];
                var imgBtn = (ImageButton)row.FindControl("EditImage");
                imgBtn.CommandArgument = row.Cells[1].Text; //GET THE ID(VALUE IN FIRST COLUMN)
             }
    }