The few examples of sorting an SPGridView I have found use a DataSet which then allows you to use a DataView to sort the contents of the SPGridView.
I am using a CAML query as my data source so this is not possible, instead I pass the sort expression and sort direction to the query and handle the sorting that way.
First of all I create a sorting event and add this to the SPGridView - credit for this code goes to ElPowlo :
void _gvProducts_Sorting(object sender, GridViewSortEventArgs e)
{
string lastExpression = "";
if (ViewState["SortExpression"] != null)
lastExpression = ViewState["SortExpression"].ToString();
string lastDirection = "asc";
if (ViewState["SortDirection"] != null)
lastDirection = ViewState["SortDirection"].ToString();
string newDirection = "asc";
if (e.SortExpression == lastExpression)
newDirection = (lastDirection == "asc") ? "desc" : "asc";
ViewState["SortExpression"] = e.SortExpression;
ViewState["SortDirection"] = newDirection;
PopulateSPGridView(e.SortExpression, newDirection);
}
I then populate my SPGridView using the sort criteria - in my real world project I also pass some values to filter the SPGridView but these have been left out here:
void PopulateSPGridView(string strSortExpression, string strSortDirection)
{
sdsProducts = new SPDataSource();
SPList oList = site.Lists["Pages"];
sdsProducts.List = oList;
sdsProducts.DataSourceMode = SPDataSourceMode.List;
string strSortDirectionBool = "";
//Convert asc and desc to True and False for use in the CAML query
if(strSortDirection == "asc")
{
strSortDirectionBool = "True";
}
else
{
strSortDirectionBool = "False";
}
sdsProducts.SelectCommand = "<ViewFields><FieldRef Name='Product_x0020_ID' /><FieldRef Name='Title' />"
+ "<FieldRef Name='Brand' /><FieldRef Name='Chemistry' />"
+ "</ViewFields><Query><OrderBy><FieldRef Name='" + strSortExpression + "' Ascending='" + strSortDirectionBool + "' /></OrderBy></Query>";
_gvProducts.DataSource = sdsProducts;
_gvProducts.DataBind();
}
For more information on CAML queries and a useful CAML Query Builder have a look at Patrick Tissegham's U2U site