Gridview使用Linq查詢數據源排序

Question

我想按列狀態和日期時間對網格視圖進行排序。我沒有設置gridView的DataSourceID屬性，因此我使用ViewState變量跟蹤排序表達式和排序方向。 DatabindgOrgEventListing中的狀態和方向是正確的，但gridview不顯示排序。

<asp:UpdatePanel ID="uplOrgEventListing" runat="server"> 
    <ContentTemplate> 
     <asp:GridView ID="grdOrgEventListing" runat="server" DataKeyNames="Id" AutoGenerateColumns="false" 
      CssClass="gridorgeventlisting" AlternatingRowStyle-CssClass="gridorgeventlistingaltrow" AllowSorting="true" 
      OnSelectedIndexChanged="grdOrgEventListing_SelectedIndexChanged" OnSorting="grdOrgEventListing_Sorting"> 
      <Columns> 
       <asp:BoundField DataField="Name" HeaderText="College Fair Name"> 
        <ItemStyle Width="375px" /> 
       </asp:BoundField> 
       <asp:BoundField DataField="City" HeaderText="City"> 
        <ItemStyle Width="135px" /> 
       </asp:BoundField> 
       <asp:BoundField DataField="State" HeaderText="State" SortExpression="State"> 
        <ItemStyle Width="35px" /> 
       </asp:BoundField> 
      <asp:BoundField DataField="DateAndTime" HeaderText="Date &amp; Time" SortExpression="DateAndTime"> 
        <ItemStyle Width="290px" /> 
       </asp:BoundField> 
      </Columns> 
     </asp:GridView> 
    </ContentTemplate> 
    <Triggers> 
     <asp:AsyncPostBackTrigger ControlID="ddlState" EventName="SelectedIndexChanged" /> 
    </Triggers> 
</asp:UpdatePanel> 



    private string GetSortDirection(string column) 
    { 
     string sortDirection = "DESC"; 
     string sortExpression = ViewState["SortExpression"] as string; 

     if (sortExpression != null) 
     { 
      if (sortExpression == column) 
      { 
       string lastDirection = ViewState["SortDirection"] as string; 
       if ((lastDirection != null) && (lastDirection == "DESC")) 
       { 
        sortDirection = "ASC"; 
       } 
      } 

     } 
     else 
      sortDirection = "ASC"; 

     ViewState["SortDirection"] = sortDirection; 
     ViewState["SortExpression"] = column; 

     return sortDirection; 
    } 

    protected void grdOrgEventListing_Sorting(object sender, GridViewSortEventArgs e) 
    { 
     GetSortDirection(e.SortExpression); 
     DatabindgOrgEventListing(); 
    } 




    private void DatabindgOrgEventListing() 
    { 
     List<OrgEvent> orgEvents; 
     List<OrgEventListing> orgEvents2; 

     using (TlMainEntities context = new TlMainEntities()) 
     { 
      context.States.MergeOption = MergeOption.NoTracking; 
      context.OrgEvents.MergeOption = MergeOption.NoTracking; 

      if (ddlState.SelectedIndex > 0) 
       orgEvents = OrgEventsByStateQuery(
        context, Convert.ToInt32(ddlState.SelectedValue), DateTime.Now).ToList(); 
      else 
       orgEvents = OrgEventsQuery(context, DateTime.Now).ToList(); 
     } 

     string sortDirection = ViewState["SortDirection"] as string; 
     string sortExpression = ViewState["SortExpression"] as string; 

     orgEvents2 = 
       (from orge in orgEvents 
       select new OrgEventListing 
       { 
        Id = orge.Id, 
        City = orge.City, 
        State = TlMainUtilities.StateSelectCode(orge.StateId), 
        Name = orge.Name, 
        DateAndTime = (
         orge.StartDate != null ? 
         ((DateTime)orge.StartDate).ToString("ddd, MMM dd, yyyy") + " " + 
         ((DateTime)orge.StartDate).ToString("h:mmtt").ToLower() + " - " + (
          orge.EndDate != null ? 
          ((DateTime)orge.EndDate).ToString("h:mmtt").ToLower() : 
          String.Empty 
         ) : 
         String.Empty 
        ) 
       }).ToList(); 
     if (sortExpression == "State") 
     { 
      if (sortDirection == "ASC") 
       orgEvents2.OrderBy(x => x.State).ToList(); 
      else 
       orgEvents2.OrderByDescending(x => x.State).ToList(); 
     } 
     else 
     { 
      if (sortDirection == "ASC") 
       orgEvents2.OrderBy(x => x.DateAndTime); 
      else 
       orgEvents2.OrderByDescending(x => x.DateAndTime); 
     } 
     //orgEvents2.Sort(); 
     grdOrgEventListing.DataSource = orgEvents2; 

     grdOrgEventListing.DataBind(); 
    } 

Answer 1

我改變了下面的代碼

 if (sortExpression == "State") 
    { 
     if (sortDirection == "ASC") 
      orgEvents2.OrderBy(x => x.State).ToList(); 
     else 
      orgEvents2.OrderByDescending(x => x.State).ToList(); 
    } 
    else 
    { 
     if (sortDirection == "ASC") 
      orgEvents2.OrderBy(x => x.DateAndTime); 
     else 
      orgEvents2.OrderByDescending(x => x.DateAndTime); 

對此

  if (sortExpression == "State") 
     { 
      if (sortDirection == "ASC") 
       orgEvents2 = orgEvents2.OrderBy(OrgEventListing => OrgEventListing.State).ToList(); 
      else 
      { 
       orgEvents2 = orgEvents2.OrderByDescending(OrgEventListing => OrgEventListing.State).ToList(); 
      } 
     } 
     else 
     { 
      if (sortDirection == "ASC") 
       orgEvents2 = orgEvents2.OrderBy(OrgEventListing => OrgEventListing.DateAndTime).ToList(); 
      else 
       orgEvents2 = orgEvents2.OrderByDescending(OrgEventListing => OrgEventListing.DateAndTime).ToList(); 
     }