Gridview -sorting事件不起作用

Question

我有一个可编辑的GridView，我试图将排序功能添加到指定的列中。虽然我没有收到错误，但我的排序方法不起作用。能帮我了解一下我在这里缺少的东西吗？

设计：

<asp:GridView ID="gvLogNotice" 
        runat="server" 
        AutoGenerateColumns="false" 
        ShowFooter="false"
        OnRowCancelingEdit="gvLogNotice_RowCancelingEdit"
        OnRowEditing="gvLogNotice_RowEditing" 
        OnRowUpdating="gvLogNotice_RowUpdating"
        EmptyDataText="There are no data records to display."
        DataKeyNames="LogNoticeID"
        AllowPaging="true"
        AllowSorting="true"
        OnSorting="gvLogNotice_sorting"
        Width="700px">
        <Columns>
            <asp:TemplateField HeaderText="Log No." Visible="false">
                <ItemTemplate>
                    <%#Eval("LogNoticeID")%>
                </ItemTemplate>
                <EditItemTemplate>
                    <asp:TextBox ID="txtLogNoticeID" runat="server" Enabled="false" Text=' <%#Eval("LogNoticeID") %>'></asp:TextBox>
                </EditItemTemplate>
             </asp:TemplateField>
            <asp:TemplateField HeaderText="Log Date" SortExpression="DateLogged">
                <ItemTemplate>
                    <%#Eval("DateLogged")%>
                </ItemTemplate>
                <EditItemTemplate>
                    <asp:TextBox ID="txtDateLogged" runat="server" Text=' <%#Eval("DateLogged") %>'></asp:TextBox>
                </EditItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField HeaderText="Log Description" HeaderStyle-Width="50px" sortexpression="LogNoticeDescript">
                <ItemTemplate>
                    <%#Eval("LogNoticeDescript")%>
                </ItemTemplate>
                <EditItemTemplate>
                    <asp:TextBox ID="txtLogNoticeDescript" runat="server" Text=' <%#Eval("LogNoticeDescript") %>'></asp:TextBox>
                </EditItemTemplate>
           </asp:TemplateField>
           <asp:TemplateField HeaderText="Responsible Party" sortexpression="ResponsibleParty">
                <ItemTemplate>
                    <%#Eval("ResponsibleParty")%>
                </ItemTemplate>
                <EditItemTemplate>
                    <asp:TextBox ID="txtResponsibleParty" runat="server" Text=' <%#Eval("ResponsibleParty") %>'></asp:TextBox>
                </EditItemTemplate>
          </asp:TemplateField>
             <asp:TemplateField HeaderText="Planned Date" SortExpression="PlannedDate" >
                <ItemTemplate>
                    <%#Eval("PlannedDate")%>
                </ItemTemplate>
                <EditItemTemplate>
                    <asp:TextBox ID="txtPlannedDate" runat="server" Text=' <%#Eval("PlannedDate") %>'></asp:TextBox>
              </EditItemTemplate>
          </asp:TemplateField>
           <asp:TemplateField HeaderText="Case Number" SortExpression="CaseNumber">
                <ItemTemplate>
                    <%#Eval("CaseNumber")%>
                </ItemTemplate>
                <EditItemTemplate>
                    <asp:TextBox ID="txtCaseNumber" runat="server" Text=' <%#Eval("CaseNumber") %>'></asp:TextBox>
              </EditItemTemplate>
          </asp:TemplateField>
             <asp:TemplateField HeaderText="Log Status" SortExpression="LogStatus">
                <ItemTemplate>
                    <%#Eval("LogStatus")%>
                </ItemTemplate>
                <EditItemTemplate>
                    <asp:TextBox ID="txtLogStatus" runat="server" Text=' <%#Eval("LogStatus") %>'></asp:TextBox>
                </EditItemTemplate>
          </asp:TemplateField>
            <asp:TemplateField HeaderText="Edit">
                <ItemTemplate>
                    &nbsp;&nbsp;
                    <asp:ImageButton ID="ImageButton1" runat="server" ImageUrl="images/edit.png" Width="25"
                        Height="25" CommandName="Edit" />&nbsp;&nbsp;
                   <%-- <asp:ImageButton ID="ImageButton2" runat="server" ImageUrl="~/img/delete.png" CommandName="Delete"
                        OnClientClick="return confirm('Are you sure want to delete record?')" />--%>
                </ItemTemplate>
                <EditItemTemplate>
                    <asp:LinkButton ID="LinkButton1" runat="server" CommandName="Update">Update</asp:LinkButton>&nbsp;&nbsp;
                    <asp:LinkButton ID="LinkButton2" runat="server" CommandName="Cancel">Cancel</asp:LinkButton>
                </EditItemTemplate>
              </asp:TemplateField>
        </Columns>
    </asp:GridView>

代码背后：

//页面加载事件：

 protected void Page_Load(object sender, EventArgs e)
    {
        lblmsg.Text = "";
        if (!Page.IsPostBack)
        {
            gvLogNotice.ShowFooter = false;
            //Load grid data using common method
            LoadGrid();


        }
    }

//将数据绑定到GV并加载

void LoadGrid()
        {
            sqlcmd = new SqlCommand("selectActiveLogs", sqlcon);
            sqlcmd.CommandType = CommandType.StoredProcedure;
            try
            {
                sqlcon.Open();
                da = new SqlDataAdapter(sqlcmd);
                dt.Clear();
                da.Fill(dt);
                gvLogNotice.DataSource = dt;
                gvLogNotice.DataBind();


            }
            catch (Exception ex)
            {

            }
            finally
            {
                sqlcon.Close();
            }
        }

//排序事件

  protected void gvLogNotice_sorting(object sender, GridViewSortEventArgs e)
    {
        switch (e.SortExpression)
        {
            case "DateLogged":
                if (e.SortDirection == SortDirection.Ascending)
                {
                   LoadGrid();
                }
                else
                {
                    LoadGrid();
                }

                break;

           }

    }

Answer 1

只有当使用SortDirection属性将GridView绑定到DataSource控件时，才会更改GridView上的DataSource属性。否则，需要手动管理排序方向。

在这种情况下，当我们使用gridView的DataSource属性向它提供数据时，e.SortDirection总是返回Ascending。，因此只有IF语句才会被执行.。

第二点：：您需要优化的实际上只是确保您定义了一个函数来返回数据。例如，假设LoadGrid()只返回DataTable。以这种方式，您不需要定义LoadGrid()方法的重载。Morover，有了正确的实现方式，实际上根本不需要重载。

第三点：：根本不应用排序，但只需通过设置DataSource属性并调用DataBind()手动加载GridView.When数据库，就需要手动处理排序操作。

因此，首先将sortDirection存储在ViewState中。只需定义一个公共属性以获得/设置相同的属性。注意我们需要根据上面第1点存储sortDirection值

public SortDirection SortDirection    
{ 
get { 
      if (ViewState["SortDirection"] == null)
            {
                ViewState["SortDirection"] = SortDirection.Ascending;
            }
        return (SortDirection)ViewState["SortDirection"];
     }
set
    {
           ViewState["SortDirection"] = value;
    }
}

在OnSorting事件中，设置sortDirection并首先对表进行排序，然后将其加载到gridView中。

 protected void SortRecords(object sender, GridViewSortEventArgs e)
{
     string sortExpression = e.SortExpression;
     string direction = string.Empty;
        if (SortDirection == SortDirection.Ascending)
             {
                  SortDirection = SortDirection.Descending;
                  direction = " DESC";
             }
        else
            {
                 SortDirection = SortDirection.Ascending;
                 direction = " ASC";
            }
    DataTable table = this.LoadGrid(); // or this.GetDataTable(), to get only the DataTable
   // Now apply Sorting to your source of Data
    table.DefaultView.Sort = sortExpression + direction;
   // Bind the GridView
    gvLogNotice.DataSource = table;
    gvLogNotice.DataBind();
}

最后，您的LoadGrid很好，只需要填充表并返回它。

private DataTable LoadGrid()
{
      DataTable dt = new DataTable();
      sqlcmd = new SqlCommand("selectActiveLogs", sqlcon);
      sqlcmd.CommandType = CommandType.StoredProcedure;
      try
       {
            sqlcon.Open();
            da = new SqlDataAdapter(sqlcmd);
            dt.Clear();
            da.Fill(dt);
            return dt;
       }
      catch (Exception ex)
       {}
}