sorting and paging with gridview asp.net

Question

I'm trying to get a gridview to sort and page manually with no success.

The problem is that when a user clicks the column they want to sort, it sorts that page, but doesn't sort the datasource (dataview) behind the gridview. So when they progress to a different page, their sort is lost. Pretty much I'm looking for a sort that will actually sort the datasource behind the gridview. Here is what I have so far:

protected void GridView_OnSort(object sender, GridViewSortEventArgs e)     {         String sortExpression = e.SortExpression;          if (GridViewSortDirection == SortDirection.Ascending)         {             DataView myDataView = new DataView(mybll.GetItemsOrdered());             myDataView.Sort = sortExpression + " DESC";             GridView.DataSource = myDataView;             GridView.DataBind();         }         else         {             DataView myDataView = new DataView(mybll.GetItemsOrdered());             myDataView.Sort = sortExpression + " ASC";             GridView.DataSource = myDataView;             GridView.DataBind();         }     } 

Any help would be appreciated. Thanks.

Answer 1

Save your sorting order in a ViewState.

private const string ASCENDING = " ASC"; private const string DESCENDING = " DESC";  public SortDirection GridViewSortDirection {     get     {         if (ViewState["sortDirection"] == null)             ViewState["sortDirection"] = SortDirection.Ascending;          return (SortDirection) ViewState["sortDirection"];                     }     set { ViewState["sortDirection"] = value; }  }  protected void GridView_Sorting(object sender, GridViewSortEventArgs e) {     string sortExpression = e.SortExpression;      if (GridViewSortDirection == SortDirection.Ascending)     {         GridViewSortDirection = SortDirection.Descending;         SortGridView(sortExpression, DESCENDING);     }     else     {         GridViewSortDirection = SortDirection.Ascending;         SortGridView(sortExpression, ASCENDING);      }     }  private void SortGridView(string sortExpression,string direction) {     //  You can cache the DataTable for improving performance     DataTable dt = GetData().Tables[0];       DataView dv = new DataView(dt);      dv.Sort = sortExpression + direction;               GridView1.DataSource = dv;     GridView1.DataBind();          } 

Why you don't want to use existing sorting functionality? You can always customize it.

Sorting Data in a GridView Web Server Control at MSDN

Here is an example with customization:

http://www.netomatix.com/development/GridViewSorting.aspx