wpf 设置新行Datagrid的内容
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Set the content of a new row Datagrid
提问by GameAlchemist
I have a DataGrid showing some databases having quite some columns.
I would like that, when the user edit a new row, some values are set automatically.
With the windows form DataGrid that would be easy, since there's RowsAdded event handler.
But how could i handle this with the wpf DataGrid ??
Edit : my DataGrid is bound in Xaml to a public property which is an ITable. When user select a table in a ComboBox, the property is updated with corresponding table.
Yes there's autogenerating column, and the way the user can enter a new row is to edit the last blank row (default behaviour).
我有一个 DataGrid 显示一些具有相当多列的数据库。
我希望，当用户编辑新行时，会自动设置一些值。
使用 Windows 窗体 DataGrid 会很容易，因为有 RowsAdded 事件处理程序。但是我怎么能用 wpf DataGrid 处理这个？
编辑：我的 DataGrid 在 Xaml 中绑定到一个公共属性，它是一个 ITable。当用户在 ComboBox 中选择一个表格时，该属性会更新为相应的表格。是的，有自动生成列，用户输入新行的方式是编辑最后一个空白行（默认行为）。
采纳答案by GameAlchemist
Ok i think i got it.
When a DataTable is bound to a DataGrid, a CollectionView is created in order to see it. You can get it by using the (static/shared) CollectionView.GetDefaultView(ThePropertyThatIsBound) method.
Since it implements ICollectionChanged, you can add an event handler to the CollectionChangedEvent.
好的，我想我明白了。
当 DataTable 绑定到 DataGrid 时，会创建一个 CollectionView 以便查看它。您可以使用（静态/共享）CollectionView.GetDefaultView(ThePropertyThatIsBound) 方法获取它。
由于它实现了 ICollectionChanged，您可以向 CollectionChangedEvent 添加一个事件处理程序。
In the CollectionChanged event handler, if you have a new item (e.NewItems.Count>0) you must check it against System.Windows.Data.CollectionView.NewItemPlaceholder and if it is not a place holder, then it is a brand new item, for wich i can set all default values.
在 CollectionChanged 事件处理程序中，如果您有一个新项目（e.NewItems.Count>0），您必须对照 System.Windows.Data.CollectionView.NewItemPlaceholder 检查它，如果它不是占位符，则它是一个全新的项目，为此我可以设置所有默认值。
回答by Eirik
You can do this in the LoadingRow event. Try something like this:
您可以在 LoadingRow 事件中执行此操作。尝试这样的事情：
private void myDataGrid_LoadingRow(object sender, System.Windows.Controls.DataGridRowEventArgs e)
{
MyObject myObject = e.Row.Item as MyObject;
if (myObject != null)
{
myObject.PropertyOne = "test";
myObject.PropertyTwo = 2;
}
}
回答by Samidjo
Assign a CollectionViewSourceto your DataGridthen listen to the CollectionChangedevent as following :
分配一个CollectionViewSource给你DataGrid然后听CollectionChanged事件如下：
..
public CollectionViewSource ViewSource { get; set; }
..
this.ViewSource = new CollectionViewSource();
this.ViewSource.Source = new List<YourObjectType>();
this.ViewSource.View.CollectionChanged += View_CollectionChanged;
..
private void View_CollectionChanged(object sender,System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
if (e.NewItems.Count > 0)
{
YourObjectType myObject = e.NewItems[e.NewItems.Count-1] as YourObjectType;
if (myObject != null)
{
myObject.Property = TheValueYouWant;
..
}
}
}
..
<DataGrid ItemsSource="{Binding ViewSource.View}" ../>
