GridView 排序:SortDirection 总是升序 [英] GridView sorting: SortDirection always Ascending

问题描述

我有一个 gridview，当用户单击标题时，我需要对其元素进行排序.
它的数据源是一个 List 对象.

I have a gridview and I need to sort its elements when the user clicks on the header.
Its datasource is a List object.

aspx 是这样定义的:

The aspx is defined this way :

<asp:GridView ID="grdHeader" AllowSorting="true" AllowPaging="false" 
    AutoGenerateColumns="false" Width="780" runat="server"  OnSorting="grdHeader_OnSorting" EnableViewState="true">
    <Columns>
        <asp:BoundField DataField="Entitycode" HeaderText="Entity" SortExpression="Entitycode" />
        <asp:BoundField DataField="Statusname" HeaderText="Status" SortExpression="Statusname" />
        <asp:BoundField DataField="Username" HeaderText="User" SortExpression="Username" />
    </Columns>
</asp:GridView>

后面的代码是这样定义的:
第一次加载:

The code behind is defined this way :
First load :

protected void btnSearch_Click(object sender, EventArgs e)
{
    List<V_ReportPeriodStatusEntity> items = GetPeriodStatusesForScreenSelection();
    this.grdHeader.DataSource = items;
    this.grdHeader.DataBind();
}

当用户点击标题时:

protected void grdHeader_OnSorting(object sender, GridViewSortEventArgs e)
{
    List<V_ReportPeriodStatusEntity> items = GetPeriodStatusesForScreenSelection();
    items.Sort(new Helpers.GenericComparer<V_ReportPeriodStatusEntity>(e.SortExpression, e.SortDirection));
    grdHeader.DataSource = items;
    grdHeader.DataBind();
}

我的问题是 e.SortDirection 总是设置为 Ascending.
我有一个类似代码的网页，它运行良好，e.SortDirection 在升序和降序之间交替.

My problem is that e.SortDirection is always set to Ascending.
I have webpage with a similar code and it works well, e.SortDirection alternates between Ascending and Descending.

我做错了什么?

推荐答案

您可以使用会话变量来存储最新的排序表达式，下次对网格进行排序时，将网格的排序表达式与存储的会话变量进行比较最后排序表达式.如果列相等，则检查先前排序的方向并按相反方向排序.

You can use a session variable to store the latest Sort Expression and when you sort the grid next time compare the sort expression of the grid with the Session variable which stores last sort expression. If the columns are equal then check the direction of the previous sort and sort in the opposite direction.

示例:

DataTable sourceTable = GridAttendence.DataSource as DataTable;
DataView view = new DataView(sourceTable);
string[] sortData = ViewState["sortExpression"].ToString().Trim().Split(' ');
if (e.SortExpression == sortData[0])
{
    if (sortData[1] == "ASC")
    {
        view.Sort = e.SortExpression + " " + "DESC";
        this.ViewState["sortExpression"] = e.SortExpression + " " + "DESC";
    }
    else
    {
        view.Sort = e.SortExpression + " " + "ASC";
        this.ViewState["sortExpression"] = e.SortExpression + " " + "ASC";
    }
}
else
{
    view.Sort = e.SortExpression + " " + "ASC";
    this.ViewState["sortExpression"] = e.SortExpression + " " + "ASC";
}

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