ASP.NET Gridview在第一次單擊時未排序

Question

我有一種情況，當我第一次單擊gridview的ItemID標頭進行降序排序時，它仍然保持升序排序。 只有在第二次單擊時，它才進行降序排列。 這是我的代碼：

protected void MyDropDown_SelectedIndexChanged(object sender, EventArgs e)
{
    this.ViewState["SortExpression"] = "ItemID";
    this.ViewState["SortDirection"] = "ASC";
    BindMyGrid();
}

public void BindMyGrid()
{        
    string sortExpression = this.ViewState["SortExpression"].ToString();
    string sortDirection = this.ViewState["SortDirection"].ToString();
    string strsql = "SELECT * FROM [MasterTbl]  ORDER BY " + sortExpression + " " + sortDirection + "";
    MyDataSource.SelectCommand = strsql;
}

protected void MyGridView_Sorting(object sender, GridViewSortEventArgs e)
{
    string sortExpression = this.ViewState["SortExpression"].ToString();
    string sortDirection = this.ViewState["SortDirection"].ToString();

    if (sortExpression == e.SortExpression)
    {
        this.ViewState["SortDirection"] = (sortDirection == "ASC") ? "DESC" : "ASC";
    }
    else
    {
        this.ViewState["SortExpression"] = e.SortExpression;
        this.ViewState["SortDirection"] = "ASC";
    }

    this.BindMyGrid();
}

HTML代碼：

 <asp:GridView ID="MyGridView" runat="server" CssClass="table table-striped table-bordered table-hover" AutoGenerateColumns="False" 
            DataSourceID="MyDataSource"  AllowPaging="true" onpageindexchanging="MyGridView_PageIndexChanging" OnRowDataBound="MyGridView_RowDataBound"
            AllowSorting="true" OnSorting="MyGridView_Sorting" OnRowCreated="MyGridView_RowCreated">
     <Columns>
           <%--Here is where my Boundfield columns are--%>
     <Columns>
     <PagerStyle CssClass="pagination-ys" />
 </asp:GridView>
 <asp:SqlDataSource ID="MyDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:DBCS %>"                     
 </asp:SqlDataSource>

真正讓我感到困惑的是，當我進入調試模式時，strsql將返回

SELECT * FROM [MasterTbl]  
ORDER BY ItemID DESC

第一次點擊，但實際上並不會強制其執行降序排列。 然后第二次點擊，它將返回

SELECT * FROM [MasterTbl]  
ORDER BY ItemID ASC

但隨后它以降序排列。

Answer 1

我已復制了問題，並嘗試了很多事情，才能正確的行為，同時保持DataSourceID="MyDataSource"中的聲明MyGridView ，沒有成功。

使它起作用的唯一方法是從GridView的標記中刪除DataSourceID屬性，並在后面的代碼中設置數據源：

public void BindMyGrid()
{        
    string sortExpression = this.ViewState["SortExpression"].ToString();
    string sortDirection = this.ViewState["SortDirection"].ToString();
    string strsql = "SELECT * FROM [MasterTbl]  ORDER BY " + sortExpression + " " + sortDirection + "";
    MyDataSource.SelectCommand = strsql;
    MyGridView.DataSource = MyDataSource;
    MyGridView.DataBind();
}

這就是我將數據源與數據綁定控件一起使用的方式，而我從未經歷過問題中描述的奇怪行為。