Gridview is sorting but Unable to add Gridview with ascending descending arrows..How to add?

Question

This is my code for adding gridview with arrows..Gridview is sorting by ascending and descending but i am unable to add arrows.

protected void grdInformation_RowCreated(object sender, GridViewRowEventArgs e)
{
    if (e.Row != null && e.Row.RowType == DataControlRowType.Header)
    {
        foreach (TableCell cell in e.Row.Cells)
        {
            if (cell.HasControls())
            {
                LinkButton button = cell.Controls[0] as LinkButton;
                HtmlGenericControl gv = new HtmlGenericControl("div");

                Label lnkName = new Label();
                lnkName.Text = button.Text;

                if (button != null)
                {
                    Image imageSort = new Image();
                    imageSort.ImageUrl = "~/images/asc.png";

                    if (grdInformation.SortExpression == button.CommandArgument)
                    {
                        if (grdInformation.SortDirection == SortDirection.Ascending)
                        {
                            imageSort.ImageUrl = "~/images/desc.png";
                        }
                        else
                        {
                            imageSort.ImageUrl = "~/images/asc.png";
                        }
                    }

                    gv.Controls.Add(lnkName);
                    gv.Controls.Add(imageSort);
                    button.Controls.Add(gv);
                    }
                }
            }
        }
    }
}}

Dono where i am going wrong , I have took an event for sorting , this is my code for sorting gridview it is working finee, but i am unable to add arrows to the girdview , the above i have tried but its not adding me arrows, how do i add arrows ??

i have tried some articles but i am unable to add arrows with ascending and descending , gridview is sorting when clicking on header rows , but need to display to the user that he can sort based on ascending arrows and descending arrows ...

 protected void grdInformation_Sorting(object sender, GridViewSortEventArgs e)
 {
     if (CurrentSortExpression == e.SortExpression.ToString())
     {
         if (CurrentSortDirection == "asc")
             CurrentSortDirection = "desc";
         else
             CurrentSortDirection = "asc";
     }
     else
     {
         CurrentSortExpression = e.SortExpression.ToString();
         CurrentSortDirection = "asc";
     }

     if (e.SortExpression.Trim() == this.SortField)
     {
         this.sortDirection = (this.sortDirection == "DESC" ? "ASC" : "DESC");
      }
      else
      {
          this.sortDirection = "ASC";
      }

      ViewState["SortDirection"] = this.sortDirection;
      this.SortField = e.SortExpression;

      Bindinfo(GetInformation(ddlStatus.SelectedValue, ddlGroups.SelectedValue));
}

Please help ??

Answer 1

You can add the images like this.

System.Web.UI.WebControls.Image sortArrow = new System.Web.UI.WebControls.Image();

private void addSortImages()
{
    int columnIndex = 0;

    //set the image url
    sortArrow.ImageUrl = "~/images/asc.png";
    if (mySortDirection == SortDirection.Descending)
    {
        sortArrow.ImageUrl = "~/images/desc.png";
    }

    //check for rows in the gridview
    if (GridView1.Rows.Count > 0)
    {
        //loop all the columns
        foreach (DataControlFieldHeaderCell cell in GridView1.HeaderRow.Cells)
        {
            if (cell.ContainingField.SortExpression == mySortExpression)
            {
                columnIndex = GridView1.HeaderRow.Cells.GetCellIndex(cell);
            }
        }

        //add the image to the correct header cell
        GridView1.HeaderRow.Cells[columnIndex].Controls.Add(sortArrow);
    }
}