下拉刷新问题 [英] Drop down refresh problem

问题描述

在我的项目中，我有两个下拉菜单(
一个位置可以有n个部门.一个部门只有一个位置. 
无论如何，我在Location实体上选择了Location，在DepartmensByLocation查询中部门实体.并具有一个SelectedLocationId参数.在 运行时，当我选择一个位置时，部门已经加载，并且我选择了任何部门.

Hi,
In my project, in a form I have two drop down(combo) which are Locations and Departments.
One Location can have n Departments. One Department only has one Location. 
Anyway, I have Selected Location on Location entity, DepartmensByLocation query on Department entity. And have a SelectedLocationId parameter. At run time, when I select a Location, Department has been loaded and I select any Department.

然后，如果我更改位置，则系我仍然在那之前选择的文本.


此处为我的SelectedLocation_Chnaged事件代码.


       局部无效SelectedLocation_Changed()
        {
            SelectedLocationId = this.SelectedLocation.LocationId;


            if(this.DepartmentsByLocation.SelectedItem！= null)
            {
               如果(this.DepartmentsByLocation.SelectedItem.Location！= this.SelectedLocation)
                    this.DepartmentsByLocation.SelectedItem = null;
            }
        }


它永远不会进入(this.DepartmentsByLocation.SelectedItem = null;)代码.因为当我选择一个位置时，系统会选择第一个位置
如果我禁用了查询，下拉菜单不会刷新...


是否可以通过任何简单的方法在连接下拉菜单时重置下拉文本


谢谢...

Then, If I change the Location, the Department text which I select before still there. This is a problem.


My SelectedLocation_Chnaged event code here.


        partial void SelectedLocation_Changed()
        {
            SelectedLocationId = this.SelectedLocation.LocationId;


            if (this.DepartmentsByLocation.SelectedItem != null)
            {
                if (this.DepartmentsByLocation.SelectedItem.Location != this.SelectedLocation)
                    this.DepartmentsByLocation.SelectedItem = null;
            }
        }


It never goes inside of the ( this.DepartmentsByLocation.SelectedItem = null;) code. Because When I select a Location, system selects the first Location item.
If  I disabled the 'Auto Execute Query' property of Queries, dropdown doesnt refresh...


Does any easy way to reset a dropdown text when its connected dropdown has a new value?


Thanks...

推荐答案

请尝试在ID上进行匹配

Please try matching on the Id's

                if (this.DepartmentsByLocation.SelectedItem.Location.Id != this.SelectedLocation.Id)
                     this.DepartmentsByLocation.SelectedItem = null;
 

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