Question

我在模板字段中将数据绑定到gridview，如：

  <asp:TemplateField HeaderText="Business Objective" SortExpression="BusinessObjective.BusinessObjectiveText">
     <ItemTemplate>
        <asp:Label ID="lblBusinessObjectiveText" runat="server" Text='<%#DataBinder.Eval(Container.DataItem, "BusinessObjective.BusinessObjectiveText") %>'></asp:Label>
     </ItemTemplate>
  </asp:TemplateField>

在后面的代码中我只是将列表绑定到网格视图：

    gvBussinessRisks.DataSource = this.BusinessRiskList;
    gvBussinessRisks.DataBind();

列表属于“BusinessRisk”类型。实体结构就像

public class BusinessRisk
{
    public BusinessRisk()
    {
        BusinessObjective BusinessObjective = new BusinessObjective();
    }

    public int? BusinessRiskId { get; set; }
    public int ObjectiveId { get; set; }
    public string BusinessRiskText { get; set; }
    public string Description { get; set; }
    public bool IsActive { get; set; }
    public long ActionedBy { get; set; }
    public long? DelegatedTo { get; set; }
    public int? LastLogId { get; set; }
    public int AppOwnerId { get; set; }

    public BusinessObjective BusinessObjective { get; set; }
}

我的BusinessObjective类具有名为“BusinessObjectiveText”的属性，我将其绑定到网格视图中的一列。

但是当我尝试对此列进行排序时，我会收到错误。

我的排序事件如下：

List<BusinessRisk> sortedList = this.BusinessRiskList;

    sortedList.Sort(new GenericComparer<BusinessRisk>(e.SortExpression, (SortDirection)Enum.Parse(typeof(SortDirection), GetSortDirection(e.SortExpression))));
    gvBussinessRisks.DataSource = sortedList;
    gvBussinessRisks.DataBind();

“GenericComparer”类是：

public class GenericComparer<T> : IComparer<T>
{
    private string sortExpression;
    private SortDirection sortDirection;
    public GenericComparer(string sortExpression, SortDirection sortDirection)
    {
        this.sortExpression = sortExpression;
        this.sortDirection = sortDirection;
    }

    public int Compare(T x, T y)
    {
        PropertyInfo propertyInfo = typeof(T).GetProperty(sortExpression);
        IComparable obj1 = (IComparable)propertyInfo.GetValue(x, null);
        IComparable obj2 = (IComparable)propertyInfo.GetValue(y, null);


        if (SortDirection == SortDirection.Ascending)
        {
            if (obj1 != null)
                return obj1.CompareTo(obj2);
            return 0;
        }
        else
        {
            if (obj1 != null)
                return obj2.CompareTo(obj1);
            return 0;
        }
    }

    public SortDirection SortDirection
    {
        get { return this.sortDirection; }
        set { this.sortDirection = value; }
    }


}

当我尝试按GenericComparer类排序此列时出错（方法：比较）我得propertyInfo为null。如果我使用BusinessRisk的属性进行排序，那么排序就会正常进行，但是在这里我尝试使用BussinessObjective类的属性进行排序。

我试过谷歌，但没有得到任何解决方案。

Answer 1

最后，在Lot of Google和小小的头脑风暴后，我得到了解决方案，使用Dynamic Linq。

我抛弃了GenericComparer类，只是在Sorting event

中编写了以下代码

string sortColumn = e.SortExpression;
    IQueryable<BusinessRisk> sortedList = (from p in this.BusinessRiskList
                                           select new BusinessRisk
                                           {
                                               BusinessRiskText = p.BusinessRiskText,
                                               IsActive = p.IsActive,
                                               Description = p.Description,
                                               BusinessObjective = new BusinessObjective { BusinessObjectiveText = p.BusinessObjective.BusinessObjectiveText }
                                           }).AsQueryable().OrderBy(e.SortExpression);




    this.BusinessRiskList = sortedList.ToList<BusinessRisk>();
    gvBussinessRisks.DataSource = sortedList;
    gvBussinessRisks.DataBind();

它的工作对我来说很完美。

谢谢所有试图帮助我的人。

使用linq对网格视图列进行排序

1 个答案: