数据绑定集合或对象列表时对网格视图进行排序 [英] Sorting a gridview when databinding a collection or list of objects

问题描述

我按以下方式设置了 GridView:

I have a GridView set up in the following way:

• 绑定到代码隐藏中的 List(我使用的是我自己的自定义 BOL)
• HTML 页面上没有数据源对象
• 可在我选择的每一列上排序(SortExpression 都设置正确)

• bound to a List<T> in code-behind (I am using my own custom BOL)
• no DataSource Object on the HTML page
• sortable on each column that I choose (the SortExpressions are all set correctly)

但是，我收到以下错误消息:

However, I am getting the following error message:

GridView 'myGridView' 触发了未处理的事件排序.

The GridView 'myGridView' fired event Sorting which wasn't handled.

让我的 List 允许排序的最佳方法是什么?

What is the best way for me to get my List<T> to allow sorting?

我怀疑这与为 OnSorting 属性指定一个函数有关，即:

I am suspecting that it will have to do with specifying a function for the OnSorting attribute, i.e.:

OnSorting = "MySortingMethod"

推荐答案

感谢您对排序的回答.我求助于 LINQ 来帮助动态排序.由于网格知道是对 ASC 还是 DESC 进行排序，以及哪个字段，因此我使用了 LINQ 表达式.表达式执行排序，然后我简单地将这些结果绑定到我的 gridview.

Thank you for your answers on the sorting. I turned to LINQ to help sort dynamically. Since the grid knows whether to sort ASC or DESC, and which field, I used a LINQ Expression. The Expression performed the sorting, and then I simply bound those results to my gridview.

我怀疑 jQuery 方法会更快，并且不需要完整的回发.

I suspect the jQuery method would be faster, and wouldn't require a full postback.

using System.Linq.Expressions;

public SortDirection GridViewSortDirection
{
    get
    {
        if (ViewState["sortDirection"] == null)
            ViewState["sortDirection"] = SortDirection.Ascending;

        return (SortDirection)ViewState["sortDirection"];
    }
    set { ViewState["sortDirection"] = value; }
}

protected void gridView_Sorting(object sender, GridViewSortEventArgs e)
{
    //re-run the query, use linq to sort the objects based on the arg.
    //perform a search using the constraints given 
    //you could have this saved in Session, rather than requerying your datastore
    List<T> myGridResults = PerfomSearch();


    if (myGridResults != null)
    {
        var param = Expression.Parameter(typeof(T), e.SortExpression);
        var sortExpression = Expression.Lambda<Func<T, object>>(Expression.Convert(Expression.Property(param, e.SortExpression), typeof(object)), param);


        if (GridViewSortDirection == SortDirection.Ascending)
        {
            myGridView.DataSource = myGridResults.AsQueryable<T>().OrderBy(sortExpression);
            GridViewSortDirection = SortDirection.Descending;
        }
        else
        {
            myGridView.DataSource = myGridResults.AsQueryable<T>().OrderByDescending(sortExpression);
            GridViewSortDirection = SortDirection.Ascending;
        };


        myGridView.DataBind();
    }
}

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