[英]Update a combobox from a presenter (MVP)
I am using MVP in my project, but i am new in MVP. 我在项目中使用MVP,但是我是MVP的新手。 I have two comboboxes.
我有两个组合框。 When I select an option in a combobox, the another combobox should be filled with new data.
当我在组合框中选择一个选项时,另一个组合框中应填充新数据。
This action will be in Presenter. 此操作将在Presenter中进行。 I get my view 'view1' in Presenter, and introduced Combobox1 and Combobox2 as properties in 'view1', because I need 'DataSource', 'DisplayMember', 'ValueMember' and 'Refresh()' in the method below.
我在Presenter中获得视图“ view1”,并在“ view1”中引入了Combobox1和Combobox2作为属性,因为在下面的方法中需要“ DataSource”,“ DisplayMember”,“ ValueMember”和“ Refresh()”。
But, when using a pattern, it is enough to send a property like 但是,当使用模式时,发送诸如
public string Combobox2
{
get { return comboBox1.SelectedValue.ToSstring(); }
}
into Presenter not the whole Combobox. 进入Presenter而不是整个组合框。 How can I solve this problem?
我怎么解决这个问题?
public void OnSelectedIndexChangedCombobox1()
{
if (view1.Combobox1.SelectedIndex == -1)
{
return;
}
DataTable dt = Tools.GetDataTable("A Path");
var query =
(from o in dt.AsEnumerable()
where o.Field<string>("afield") ==
farmerView.Combobox1.SelectedValue.ToString()
orderby o.Field<string>("anotherfield")
select new KeyValuePair<string, string>(o.Field<string>("field1"),
o.Field<string>("field2"))).ToList();
farmerView.Combobox2SelectedIndexChanged -= OnSelectedIndexChangedCombobox2;
farmerView.Combobox2.DataSource = new BindingSource(query, null);
farmerView.Combobox2.DisplayMember = "Value";
farmerView.Combobox2.ValueMember = "Key";
farmerView.Combobox2.Refresh();
farmerView.Combobox2SelectedIndexChanged +=
OnSelectedIndexChangedCombobox2;
farmerView.Combobox2.SelectedIndex = -1;
}
Thank you 谢谢
You should not pass any Android objects to presenter, just get the event in view (for instance your Activity) then call a method from presenter that provides data for second ComboBox (we call it Spinner in Android!) by passing selected item from first one, and then presenter will call a method of View which fill the second one and View knows how to do it. 您不应将任何Android对象传递给演示者,只需在事件视图中获取事件(例如您的Activity),然后从演示者中调用一个方法即可为第二个ComboBox(在Android中称为Spinner!)提供数据,方法是传递第一个对象中的选定项,然后演示者将调用View的方法,该方法将填充第二个方法,并且View知道如何执行此方法。
You can take a look at this sample project http://github.com/mmirhoseini/marvel and this article https://hackernoon.com/yet-another-mvp-article-part-1-lets-get-to-know-the-project-d3fd553b3e21 to get more familiar with MVP. 您可以看一下这个示例项目http://github.com/mmirhoseini/marvel和本文https://hackernoon.com/yet-another-mvp-article-part-1-lets-get-to-know -the-project-d3fd553b3e21以更熟悉MVP。
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