Question

我尝试了下面的排序功能

<asp:GridView ID="grdUser"
                AllowPaging="true"
                AutoGenerateColumns="False"
                OnDataBound="grdUser_DataBound"
                OnRowDeleting="grdUser_RowDeleting"
                OnPreRender="PreRenderGrid"
                runat="server"
                Width="100%"
                border="1"
                DataKeyNames="Id"
                PageSize="10"
                EmptyDataText="No Records Found"
                OnPageIndexChanging="grdUser_PageIndexChanging"
                EnableSortingAndPagingCallbacks="false"
                CssClass="hoverTable"
                AllowSorting="true"
                OnSorting="grdUser_Sorting"
                ShowFooter="false"
                HeaderStyle-CssClass="k-grid td"
                OnRowCommand="grdUser_RowCommand">
                <AlternatingRowStyle CssClass="k-alt" />
                <Columns>
                    <asp:TemplateField HeaderText="Select" ItemStyle-Width="5">
                        <ItemTemplate>
                            <asp:CheckBox ID="chkDelete" runat="server" />
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:BoundField DataField="username" HeaderText="Username" SortExpression="username" ItemStyle-Width="30" />
                    <asp:BoundField DataField="email" HeaderText="Email ID" SortExpression="email" ItemStyle-Width="30" />
                    <asp:BoundField DataField="ngoname" HeaderText="NGO Name"  ItemStyle-Width="30" />
                    <asp:BoundField DataField="usertype" HeaderText="UserType" ItemStyle-Width="30" Visible="false" />
                    <asp:BoundField DataField="UserRoleName" HeaderText="User Role" ItemStyle-Width="30" />
                    <asp:BoundField DataField="active" HeaderText="Active" SortExpression="active" ItemStyle-Width="30" />
                    <asp:TemplateField HeaderText="Action" HeaderStyle-Width="5%">
                        <ItemTemplate>
                            <asp:ImageButton ID="btnEdit" AlternateText="Edit" ImageUrl="~/images/edit.png" ToolTip="Edit" runat="server" Width="15" Height="15" CommandName="eEdit" CommandArgument='<%# Eval("Id") %>' CausesValidation="false" />
                            <asp:ImageButton ID="btnDelete" AlternateText="Delete" ImageUrl="~/images/delete.png" ToolTip="Delete" runat="server" Width="15" Height="15" CommandName="Delete" CommandArgument='<%# Eval("Id") %>' CausesValidation="false" OnClientClick="return confirm('Are you sure you want to delete this record?')" />
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>

另见我背后的代码： -

protected void grdUser_Sorting(object sender, GridViewSortEventArgs e)
    {
        DataTable dt = Session["tbl_User"] as DataTable;
        DataView dataView = new DataView(dt);
        dataView.Sort = e.SortExpression + " " + GetSortDirection(e.SortExpression);
        grdUser.DataSource = dataView;
        grdUser.DataBind();
    }

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

但是当我调试代码时，我总是将dt视为null。请帮忙

更新

绑定gridview的代码： -

protected void BindGrid()
    {
        string username = string.Empty;
        string usertype = string.Empty;

        try
        {
            SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["DefaultCSRConnection"].ConnectionString);
            SqlCommand cmd = new SqlCommand("SELECT usertype,username  FROM tbl_User WHERE username=@username", conn);
            cmd.Parameters.Add("@username", SqlDbType.VarChar).Value = Session["User"].ToString();

            conn.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            if (dr.HasRows)
            {
                if (dr.Read())
                {
                    username = dr["username"].ToString();
                    usertype = dr["usertype"].ToString();
                }
            }
            conn.Close();

            string query = string.Empty;

            if (!string.IsNullOrEmpty(usertype))
            {
                if (usertype == "0") // superadmin
                {
                    query = "select tbl_User.Id,tbl_ngoname.ngo_name, tbl_User.username,tbl_User.email,tbl_User.usertype,tbl_User.active,(CASE WHEN tbl_User.usertype='1' THEN 'Admin' WHEN tbl_User.usertype='0' THEN 'Super Admin' WHEN tbl_User.usertype='2' THEN 'User' END) AS UserRoleName FROM tbl_User INNER JOIN tbl_ngoname on tbl_ngoname.Id = tbl_User.NgoId ORDER By Id DESC";
                }
                if (usertype == "1") // admin
                {
                    query = "select tbl_User.Id,tbl_ngoname.ngo_name, tbl_User.username,tbl_User.email,tbl_User.usertype,tbl_User.active,(CASE WHEN usertype='1' THEN 'Admin' WHEN usertype='0' THEN 'Super Admin' WHEN usertype='2' THEN 'User' END) AS UserRoleName from tbl_User INNER JOIN tbl_ngoname on tbl_ngoname.Id = tbl_User.NgoId WHERE usertype != '0' ORDER By Id DESC";
                }
                if (usertype == "2") // user
                {
                    query = "select tbl_User.Id,tbl_ngoname.ngo_name, tbl_User.username,tbl_User.email,tbl_User.usertype,tbl_User.active,(CASE WHEN usertype='1' THEN 'Admin' WHEN usertype='0' THEN 'Super Admin' WHEN usertype='2' THEN 'User' END) AS UserRoleName from tbl_User INNER JOIN tbl_ngoname on tbl_ngoname.Id = tbl_User.NgoId WHERE username='" + username + "' ORDER By Id DESC";
                }

                cmd = new SqlCommand(query, conn);

                SqlDataAdapter da = new SqlDataAdapter(cmd);

                DataSet ds = new DataSet();
                da.Fill(ds);
                grdUser.DataSource = ds.Tables[0];
                grdUser.DataBind();
                DisablePageDirections();
                grdUser.BottomPagerRow.Visible = true;
                Session["tbl_User"] = ds.Tables[0];
            }
        }

        catch (Exception)
        {
            throw;
        }
    }

添加更多代码： -

private DataTable GetData(SqlCommand cmd)
    {
        DataTable dt = new DataTable();
        SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["DefaultCSRConnection"].ConnectionString);
        SqlDataAdapter sda = new SqlDataAdapter();
        cmd.Connection = conn;
        try
        {
            conn.Open();
            sda.SelectCommand = cmd;
            sda.Fill(dt);
            return dt;
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            conn.Close();
            sda.Dispose();
            conn.Dispose();
        }
    }

Answer 1

您在页面加载时设置名为tbl_user的会话，当您获得该会话时，您将使用GridViewData。

在页面加载时，您使用名称tbl_user

设置会话

Session["tbl_User"] = dt;

你得到的名字是GridViewData

DataTable dt = Session["GridViewData"] as DataTable;

当您从grdUser_Sorting中的会话中获取数据表时，请将其更改为

 protected void grdUser_Sorting(object sender, GridViewSortEventArgs e)
{
    //Retrieve the table from the session object.
    DataTable dt = Session["tbl_user"] as DataTable;
    if (dt != null)
    {
        //Sort the data.
        dt.DefaultView.Sort = e.SortExpression + " " + GetSortDirection(e.SortExpression);
        grdUser.DataSource = Session["tbl_user"];
        grdUser.DataBind();
    }
}

排序在Gridview中不起作用

1 个答案: